(Updated January, 2010)

    This page is devoted to my experiences with the maintenance and breeding of a variety of snake species.  There are six Sections and an introductory opinion piece:
     The current Congressional effort to ban python importation.
1.  General comments on the past two years, about myself, and the types of animals that I keep.
2.  Comments on herpetoculture and conservation.
3.  Pictures and notes about the animals that I have kept.
4.  The care of Calabar Pythons (Calabaria (= Charina) reinhardti) and notes on breeding and egg incubation.
5.  Questions (and the rare answer) about snake behavior and breeding.
6.  Breeding records for the snakes I have kept and a general form to track husbandry data.

The Proposed U.S. Government Python Ban: A Larger and Potentially Fatal Issue to the Hobby Left Unaddressed:

As I write this, the process to formulate a Bill to ban python importation is still ongoing and some sort of Congressional action may be coming soon.  Given the recent apparent inability of Congress to investigate, evaluate facts and/or data, and arrive at reasonable solutions, I would be surprised if a Bill is passed that will come close to doing anything but anger both sides of the debate.  The point I would like to make here is that in the midst of all of the "drama with the United States Association of Reptile Keepers actively pushing one viewpoint and the Humane Society of the United States pushing another, everyone is ignoring an issue that in my opinion may eventually do much, much greater damage to the hobby - the importation, maintenance, breeding and sale of highly venomous snakes.   

The potential of venomous snakes to become established in many areas of the United States is a very real threat.  Places that immediately come to mind include Florida (the center of reptile importation), the Gulf States, Texas, Western United States deserts, and large parts of the West Coast.  I believe that this is a much greater threat than constrictors and it is currently being ignored by everyone - the hobby, the Public and Congress.  A quick visit to the "" classifieds indicates that for $2000, you can be the proud owner of a large collection of mambas, Death Adders, Terciopelos, Puff Adders, South American Rattlesnakes, Gaboon Vipers and spitting cobras.  Some dealers do state that they will not sell these species to people living in areas that forbid keeping venomous reptiles.  I did not, however, see any queries about potential buyers' prior experience with venomous reptiles!  No questions as to the housing planned for these animals, the food supply, the size of the collection, or any other factor that would indicate sufficient knowledge to keep these animals safely!  I believe that this existing situation is intolerable and may come back to haunt us all at some point in the future.  I have spoken to former reptile owners who bought species with little or no negative information from the dealers, or downright mis-information - a sale is a sale, and let the buyer beware.  So right now, we are ignoring a situation that could destroy our hobby.  Having a 15-foot Burmese eat a small pet dog is bad enough, but having someone quickly die after being bitten by an introduced species of venomous snake could sufficiently panic the Public (and Congress) into enacting extraordinarily intrusive laws that will make maintaining snakes as difficult as maintaining hawks.  How many deaths from mambas would have to occur in the Everglades for South Florida tourism to fall off?  How many cobra bites in a Western U.S. National Park would have people avoiding trips there?  Is there anyone who seriously thinks that such introductions are an impossibility?  I would assume that anyone who cares about the future of our hobby will know that changes are needed and the best place for these changes lies in the behavior of dealers - not in Government laws.  The exact nature of these changes will be the subject of considerable discussion, but if we do not acknowledge the difference between selling a Milksnake and selling a WC female mamba who may be gravid, there is an excellent chance that extremely unpleasant regulations will be forced upon us.  When I first started this home page about 8 years ago, I warned about the continued sales of large constrictors and highly venomous reptiles.  There are now three large constrictors established in South Florida and the hobby is scrambling to fight off Congressional Bills.  The venomous reptiles are, as far we know, still not an issue.  I would suggest that it be preemptively addressed, before public outrage and fear forces our hand. 

As of today (1-9-11), there is a chance that we will see a ban on the importation of pythons, boas, anacondas etc.  The ban may or may not include the vast majority of boas and pythons that are much smaller.  In my opinion, either outcome will have exactly the same impact on the ecological situation as not passing any bill at all - absolutely no impact.  The animals are with us and the only question remaining is how much damage they will eventually do to the environment, and to the Public's perception of a hobby that involves breeding snakes and other reptiles.  As far as the environment is concerned, there will probably be very weak data and very strong opinions.  The "iguana scenario" where a "pleasant animal" becomes established without much impact on anything will be put forth by some while others will advance the "brown tree snake scenario" where an introduced snake species devastated Guam's ecology.  Most probably, the true impact will not become evident until much later, and as I said above, the snakes are already here and passing bills is a waste of time.  Addressing potential future issues while there is still time would, in contrast, be a very constructive use of our energies.


I have been keeping snakes for a long time - seriously for about 11 years.  During that period of time I have had only one or two animals die and, I confess, I took this as being the normal state in a well-maintained collection.  Well, perhaps it is, perhaps I did things wrong during the last two years (things that I am unaware of), perhaps something major is going on that I am unaware of, and perhaps the "Law of Averages" finally caught up with me.  2008 began with 16 animals in my collection and ended with 10 animals (including 2 added during 2007).  A total of 8 animals died!  There was no real pattern - I lost my longest-term captives (1.1 WC Calabar Pythons); long-term CB animals (a 1.0 Mandarin Rat Snake and 1.1 Flame Snakes); and 3 recent WC additions, South American Green Racers (1.1 Phylodryas baroni and 1.0 P. aestiva).  The only animal where the cause of death was obvious was the female Calabar who had an everted oviduct after laying a clutch of four eggs.  2009 hasn't been much better and I lost 1.1 Baja Mountain Kingsnakes, 1.1 Calabars, and 0.1 Mandarin Ratsnakes so the collection is now down to 6 animals.  I would add that I have looked at records of longevity of snakes in captivity and all of the animals with the exception of a male Calabar were well up into the range where deaths have been recorded so I am wondering if the deaths may not have been, at least partly, simply due to age-related health issues.  All in all, though, it has been an absolutely awful period for someone who was simply not used to losing animals...


I am a scientist doing research in the area of developmental biology and toxicology.  I work at the National Health and Environmental Effects Research Laboratory of the U. S. Environmental Protection Agency.  When Claudia Bolger and I married, the household included two snakes that I had caught in Eastern North Carolina - a Pygmy Rattlesnake and a Canebrake Rattlesnake.  This was some years ago when I still thought that it was “impressive” to keep venomous reptiles.  My son Kyle was born and nothing changed until he became strong enough to climb.  At that point (23 years ago), common sense prevailed and both snakes were donated to the Natural History Museum in Durham, NC, that maintained such animals as exhibits.  The venomous snakes were traded for a Corn Snake and the hobby remained at that stage until about twelve years ago when the collection began to expand.  A major reason for the expansion is that two other scientists who were working with me at the EPA were also interested in snakes (one has since retired).  Lunchtime conversations revolving around the four "eedings" of snake keeping (feeding, bleeding, breeding, and eating) are far more interesting than the latest useless and intrusive managerial schemes hatched by the always active and therefore increasingly burdensome bureaucratic overhead. 


    The choice of animals in my collection is based on a number of factors including the extent of the resources (space, time, expense) that I can devote to the hobby; personal preferences including appearance, habits, and size; and lack of breeding records in captivity.  After the disastrous years I referred to above, my collection now consists of the following:
1.0 Mandarin Rat Snake (Elaphe mandarina) - A beautiful juvenile male that is doing well.
0.0 "Flame Snake" (Oxyrhopus rhombifer inaequifasciatus) - A rarity in collections, this is a beautiful rear-fanged subspecies.  I had a pair for some time and this year, both animals died some months apart.  I am still listing the (yes, a "0.0" is a bit odd) because I did purchase some hatchlings that are currently being moved from lizards to mice and when the process is complete, I will take possession - sometime in 2010.
1.1 African Mole Snake (Pseudaspis cana) - Another rarity in collections, this is a nice looking constrictor that is very rarely bred in captivity.
1.0 Brazilian Rainbow Boa (Epicrates cenchria cenchria) - A spectacular, iridescent boa that is tractable and reaches a moderate adult size.  As with the Mandarin Rat Snake, my animal is one half of a breeding pair that I share with a friend.
1.1 Mussuranas (Boiruna maculata
(formerly Clelia occipitolutea)) - The only additions to my collection these past two years.  This is another rarely seen South American species.  They are large rear-fanged constrictors.

  These animals meet some or all of a number of criteria that I consider essential before introducing a species into the collection:
  They are all reasonable size as adults since, for me, there is little sense in keeping animals that grow large enough to require sizable resources in terms of food and caging.  I would far rather keep a variety of smaller animals than a small number of extremely large ones.  I also feel that large boids are potentially harmful to the hobby.  Every time there is a news story about a large constrictor that has hurt a pet or child, or has terrorized an apartment house or neighborhood, a large number of people call for the prohibition of all "exotic" animals as pets.  The ready availability of Burmese, Reticulated, and African Rock Pythons does little to advance the hobby or change the public's impression that those of us who keep snakes are boozing, tattooed, knuckle walkers.  Another problem with these animals has gone from the theoretical to the real in the last few years - the possibility that the release of these animals into the wild by people who could no longer take care of 10+ feet-long animals would result in established, breeding populations.  Burmese Pythons have now become extremely common in many parts of the Everglades and have become established on Key Largo as well.  The possible ecological damage that they may do (along with the breeding populations of Nile Monitors now established in the West Coast of Florida) is currently unknown - but given the sensitivity of these ecological systems due to human impacts, it is not unreasonable to expect that considerable damage may be done over time.

   Part of the advantage of all of these species is that whether relatively common or extremely uncommon in the hobby, their offspring are relatively expensive and have paid or will pay for a portion of the expenses over the year.
  An extremely important consideration is rarity in collections and/or lack of information concerning captive breeding.  These factors figured prominently in my decision to purchase Calabars, Oxyrhopus, the African Mole Snake, and the Mussuranas since these species are not generally bred in captivity and offer that additional challenge. 

I do not maintain "designer" color varieties or morphs.  While I appreciate the beauty of some specifically bred color variants, they are rare exceptions to my impression that animals with natural coloration and patterns are far more attractive than cultivars.  My job as a toxicologist specializing in the study of birth defects also results in an avoidance of traits that are normally considered defects (e.g. albinism).  Inbreeding for visible defective traits may also lead to a similar segregation of other undesirable traits that are not as apparent.  This is especially true for animals such as those that are piebald since the characteristic patches of albino skin result from abnormal embryogenesis and may be associated with other defects.  I also believe that the current craze revolving around the sale and breeding of extremely expensive "designer Ball Pythons" will, in the end, cost many people a great deal of money that they will be unable to recoup.  I would suggest that anyone reading this who has thought of purchasing a "piebald, spider, crimson, het for snow, striped, spotted Ball Python" look up "tulipmania" in the Wikipedia.  I consider inter-species and subspecies crosses to be detrimental to herpetoculture and not worthy of discussion.


The idea that herpetoculture could and should play a positive role in the conservation of species has been advanced by a number of people within the hobby.  This is largely based on two factors - the possibility that animals maintained within the hobby will form a repository of species that could, at some later time, be introduced into the wild thereby increasing natural populations or replacing those that have disappeared; and the reduction of collecting pressures on existing populations through the increased use of captive born animals.  The validity of both of these ideas is, however, very much in doubt.  There are extraordinary difficulties involved in the introduction of captive animals back into the wild.  It is generally agreed that unless essential precautions are taken over a long period of time, there is a very real danger of introducing alien microbes into the environment along with the target species.  For example, my collection is housed in one room and currently contains one wild caught species, the Calabar Python and the remainder purchased at different times from different breeders.  None of the animals, either wild caught or captive born, have been kept in the type of cages and/or room that provides fungal, bacterial, and/or viral isolation.  While I have made efforts to use disposable gloves while cleaning cages and feeding, there have certainly been numerous lapses.  It is therefore probable that all the animals have been exposed to the complete array of potential disease-causing organisms in the room.  The possibility does exist that the deaths that occurred in my group this past year resulted from alien microbes attacking species with no natural immunity - or lacking normal immunity due to long-term adverse health status due to the stress of captivity.  Currently, they are given clean water and parasite free food, and do not face many of the natural stressors that wild populations have to deal with.  Such stresses in animals reintroduced into the wild may make them susceptible to opportunistic pathogens they have been formerly exposed to from other animals that were housed in the same room.  More importantly, releasing these animals back into the wild might allow some pathogen to invade wild populations of these and other species with possibly devastating results.  A Chytrid fungus and various viruses have been proposed as key contributors to the global decline of frogs.  This follows an alarming pattern of "emerging infectious diseases" (EIDs) that have affected a diverse group of animals and plants globally.  These pathogens may have been spread into amphibian populations by tourists, or by the herpetologists who were studying these animals.  As travel becomes more accessible to larger numbers of people, the global spread of disease causing entities becomes more of a probability than a possibility - witness the spread of HIV. 
    Some years ago, I went to the Monte Verde Rain Forest Preserve in Costa Rica.  Until recently, the Preserve was home to the Golden Toad (Bufo periglenes), which is now extinct due to fungal infection, and is to be found only on T-shirts and hotel signs.  On a Tuesday morning I made a last check on my snakes, cleaned some cages, and changed the water.  That afternoon I flew to Costa Rica and spent the night in San Jose.  Wednesday morning a car was rented, and I was walking in the rain forest by 4:00.  A single day after I had been dealing with a fair number of snake species, all of them exotic to Costa Rica, I was walking through the Park and areas around it.  At the sides of the roads in the region, I would lift the occasional rock or turn a log looking for snakes.  Since I was very conscious of the possibility of my inadvertently leaving unwelcome microbes in that environment, I had showered before the flight and taken only clothes that had just been washed.  It certainly didn't reduce the threat to nil, but I felt that it was a prudent precaution.  I wonder, however, how many others (including herpetologists) have done the same.

    Even if we could take the proper precautions and had animals that were isolated from other species, it would still be very difficult to successfully introduce a species into the wild.  Long-term captivity and breeding programs result in populations of animals that may be functionally and behaviorally different from wild counterparts.  Those of us active in the hobby know how easy it is to breed for various color and pattern traits.  At the same time, we are also selecting for other far less obvious (or invisible) traits.  Selective breeding for prize winning German Shepherd show dogs resulted in the introduction of hip dysplasia in the breed and there are numerous breeds known to be associated with adverse health effects.  By the very nature of the hobby, we tend to select animals with large litter or clutch sizes - traits that may prove to be a disadvantage for snakes in the wild.  Similarly, we will probably select for individuals that eat the food items we have access to.  It would not be surprising if, over time, the average captive Gray Banded Kingsnake hatchling (Lampropeltis mexicana alterna) takes mouse pups as first food much more readily than lizards, its usual initial prey.  This behavioral shift would simply reflect the decreased reproductive potential for those animals that accept only live lizards as their first food and/or are difficult feeders and therefore either fail to thrive or do not achieve reproductive maturity as rapidly.  Should a change of this nature take place, it might not be accompanied by any morphological alteration, and may be welcomed by the hobbyist – but the release of such animals into the wild might result in total failure if their offspring are not equipped to accept their normal initial food species.  Recent evidence has been published indicating that captive-reared salmon raised in aquaculture farms do not survive as well when released into the wild as do WC fish.  The reasons for these differences are not, as yet, known but it should be apparent that the same traits that enable animals to survive in an aquaculture environment may be detrimental when attempting to survive and breed in the natural environments.    

 As far as reducing pressure on wild populations through captive breeding, this is certainly true, but it will have a minute positive impact on population sizes when compared to the negative effects of habitat destruction and/or fragmentation.  The reverse argument that the effects of removing small numbers of a species such as the Amazonian Emerald Tree Boa (Corallus caninus) from the Amazon will substantively alter the future of this species is also nonsense for the same reason.  The removal of animals from the wild for the pet trade does not begin to compare with the dangers posed by continued degradation of the environment.  Certainly, pouring a cup of water into a flooded basement with a broken water main doesn't help the situation - but to argue that the cup of water will significantly worsen the problem ignores reality.
    There are certainly positive things that herpetoculturists can do to conserve reptile biodiversity.  Species such as the Pere David’s Deer, the European Bison, and Asiatic Camel, exist only in captivity, and given the continued loss of suitable habitat, numerous species of snakes may join this group.  Herpetoculturists who are serious about the need to preserve species diversity have two roles to play.  The first, and the most important, is to support governmental and private efforts to stop the accelerating global habitat destruction.  The second role is to devote a significant portion of our energies in the maintenance of species as close to their wild forms as is possible - that is, to avoid the continual creation of aberrant cultivars and to attempt to maintain diverse genetic history in the animals we breed.  During the past few years I have become acquainted with a number of other hobbyists who share my enthusiasm for maintaining species that are relatively rare in captivity.  They keep species that are seldom, if ever, present on dealer lists and some of their animals are sufficiently rare as to require a Fish and Wildlife Service Permit to legally own.  We all have long lists of genera that we would like to obtain - and none of us can locate dealers that import them.  In an effort to lessen the effects of over-collecting, Governments have erected a series of barriers to the exportation/importation of all species, regardless of rarity.  These barriers often are far more formidable for live specimens than for skins, but that simply reflects economic realities.  It is easier for a Nation to control a handful of powerless exporters of live animals than it is to deal with powerful business interests doing a thriving trade in animal products (although the January, 2010 Issue of the National Geographic Magazine has an devoted to the power of the illegal animal exportation and importation industry).  Similarly, it is easier for some environmentalists to rail against "pet keepers" than to deal with government policies that destroy the environment.  The end result of all of this is that dealers are often understandably reluctant to go to the trouble of importing these animals given the enormous amounts of paperwork and expense involved in obtaining specimens that do not command nearly the same prices that the latest piebald, het-for-albino Ball Python   does.  I hope that over the years, an increasing number of hobbyists will move beyond the latest fad animals and seriously consider the challenges of attempting to maintain species that are now unknown or extremely rare in herpetoculture.  Animals in captivity are certainly no substitute for having them viable in their native habitats, but at least we will eventually have a wide representation of a group whose beauty and grace is a continual pleasure to all of us.



Calabar Pythons (Calabaria (= Charina) reinhardti)

3-foot female Calabar; yellow and brown
An adult female Calabar Python 3'1" length, 630g weight, 2004.

A Calabar hatchling; red and brown color
A 2-month old neonate Calabar Python showing the typical red and brown coloration.
The ruler in the picture is 6 1/2 inches in length.

The Calabar Pythons are one of the first species that I kept and bred.  I have described my experiences with the husbandry of these interesting animals in a Section below.

0.1 Mountain Kingsnakes (Lampropeltis zonata agalma); 11/97

 Mountain Kingsnake - male - 2006

Mountain Kingsnake - female -2006 

  Baja Mountain Kingsnakes, 2006.  Male above, female below.

The California Mountain Kingsnake is one of the more attractive Kingsnake tricolor species.  

1.0 Brazilian Rainbow Boa (Epicrates cenchria cenchria); adult, 1/99

  Adult Brazilian Rainbow Boa, 5' in length.
An adult male Brazilian Rainbow Boa approximately 6' in length, with the beautiful coloring characteristic of this subspecies, 2006.

Head of Brazilian Rainbow Boa showing iridescence
Head of the above animal in sunlight, showing iridescence.


The iridescent Brazilian Rainbow Boa is certainly one of the most beautiful snakes.  It is a fairly popular species within the hobby although I remain puzzled as to why it is not even more commonly kept.  It is an ideal size, relatively easy to maintain, and not difficult to handle.


0.0 Flame snake (Oxyrhopus rhombifer inaequifasciatus); neonates, 5/00

June, 2006

Oxyrhopus - male - 2006Oxyrhopus - female -2006

Male (died)                                                                   Female (died)

Oxyrhopus - male - head - 2006 
Head of male

I was fortunate in being able to purchase two hatchling "Flame Snakes" in May, 2000 from Gulf Coast Reptiles in Naples, FL.  They were part of a clutch of eight eggs laid by gravid female recently imported from Paraguay.  Using the keys to species and subspecies found in the "Catalogue of Neotropical Squamata; Part I. Snakes" by J.A. Peters and B. Orejas-Miranda (1970), I determined that the animals were Oxyrhopus rhombifer inaequifasciatus,a subspecies that is found in Paraguay.  I have not located any pictures of this subspecies on the Internet so I am attaching three - a male, female, and head of the male.  Note the different coloration between the female and the male, the latter having larger red areas dorsally.  I have only seen one other specimen of this subspecies for sale and that animal was also a male  and was similar in coloration to mine.  This species is rear-fanged but I have not located any references to human envenomation.  They took live mouse pups as first food and I have continued feeding them live mice.  Based on the lack of coiling when being handled, at first I assumed that they were not constrictors but I have observed the male throwing very tight coils around a large fuzzy prior to eating it so the issue is still undecided.  I have removed mouse pups from the jaws of the female and although there was ample evidence of a bite, the mice have not exhibited any obvious signs of toxicity.  The snakes are are extremely secretive and remain under the bedding (paper) almost constantly, emerging only after the lights are out.  As they have matured, they have become less excitable and they have never shown any  tendency to bite. 
I have noted an interesting trait in both animals.  On April 16, 2004, the female had what appeared to be a swollen jaw.  I checked the male and discovered that he too had this "swollen jaw".  It appeared as though the animals had simply "puffed out" their lower jaw.  The jaws were firmly closed (no gaping that would indicate any form of infection) and the swelling seemed to vary during the course of the day.  Since the female had eaten three fuzzies during the night (the male did not eat), I decided to leave them alone and check them later.  As it turned out, the "swelling" disappeared and the animals returned to normal appearance the next day: 


I have noted this behavior additional times and the swelling has become fairly constant in the female.  In December of that year, I noted that there was also a swelling in the lower part of the neck:

I took the animal to the University of North Carolina Veterinary Hospital where it was given a thorough examination by Dr. Greg Lewbart and Mr. Larry S. Christian.  Tissue samples and swabs were taken and infections, fluid build-up, and solid masses were ruled out.  To date, the animal's condition has not changed and she continues to eat so I am simply keeping track of her appearance and monitoring  her weight.
Both animals grew rapidly - from 6-8g. at arrival to approximately 235g. for the female and 300g. for the male at the time of his death.  The husbandry of the animals are identical to those I use for corn snakes (70-75), paper bedding, hide box, and water bowl.  They are currently housed together in a 20-gallon aquarium with plastic mesh tops.  As is the case with all of my aquaria, it has an insertable  divider that enables me to track the feeding of each animals separately.  This year, the male became infected and died with what appeared to be "blister disease" - there were lesions on its ventrum.  The female died some months later with no signs of "blister disease". 

Oxyrhopus are being bred by several hobbyists in Europe and a friend and I purchased two clutches this year.  He was attempting to get them to a sufficient size to be able to eat new-born pinkies and at one point he fed them frozen, locally caught, small skinks.  Immediately after that, they became sick and died.  Subsequently, additional neonates were purchased from the same source and they are currently being converted from lizards (anoles only!) to mice.  I will take possession of animals as soon as they are taking mice without any problem.

Mandarin Rat Snakes (Elaphe mandarina); hatchling - female.

   Mandarin Rat - male - 2006

Male Mandarin Rat Snake (deceased) - Picture of current male Mandarin will be coming

Mandarin Ratsnake - female - 2006 

Female Mandarin Rat Snake (deceased).

The range of this species of rat snake is very large and there is considerable variability in the animals coming onto the market.  The male of the pair I own with a friend died this year.  They differed considerably in appearance but we have not been able to learn anything definite about their parental stocks and therefore do not know whether this is normal "within-litter" variation, or whether these animals represent geographical areas. 

1.1 African Mole Snakes (Pseudaspis cana); neonates, 4/04

Male African Mole Snake

April, 2004 (weight 22g.)

Pseudaspis - Male - 2006
June, 2006 (weight 1280g.)

Female African Mole Snake

April, 2004 (weight 24g.)

Pseudaspis - female - 2006
June 2006 (weight 1550g.)

Pseudaspis - male - head - 2006Pseudaspis - female - head - 2006
Heads of male (at left) and female illustrating general shape as well as color differences.

I have always been interested in this species and purchased this CB pair after noting them in a dealer's price list.  This is one of a large number of snakes that are, in my opinion, interesting and attractive, and yet still remain rarely offered.  They change color as they mature and eventually assume solid shades. 
From the time they arrived, they have eaten voraciously and are growing rapidly.  Their arrival weights were 14-17g. and they are currently 1500+g.  They were extremely excitable and/or irritable animals during the first year that I had them and I learned that their attempts to bite were not bluffs.  Over time, however, they have mellowed to the point where their aggression is reduced but they still do not tolerate handling. 

1.1 Mussurana (Boiruna maculata); CB 12/06

Boiruna maculata 

I purchased a pair of CB Mussuranas this past year.  This is a species that I have always wanted to keep.  It is a large rear-fanged constrictor with several species and numerous subspecies ranging from Mexico well into South America.  These animals have eaten well and have grown considerably in the time that I have had them.  They arrived weighing 40+g. and after a year, currently weigh 90+g.



During the last few years, requests for information about the husbandry of Calabar Pythons (Calabaria reinhardti) have reached me via my home page and subsequent e-mail.  Given the apparent interest in Calabars, I have decided to put the following information here in the hope that it may be useful to people who wish to keep these animals.

Taxonomy:  In 1993, the herpetologist A. G. Kluge studied the anatomy of this species and concluded that it was closely related to the Rosy Boa (Lichanura trivergitata) and the Rubber Boa (Charina bottae).  This finding placed the Calabar Python in the boa subfamily, rather than that containing the pythons.  He then combined ("lumped") the three species (Rosy Boa, Rubber Boa, and Calabar Python) into one genus, Charina.  Other herpetologists have informed me that while Kluge's conclusion that C. reinhardti is a boa rather than a python is generally accepted, his proposed taxonomic changes are still somewhat controversial although some herpetologists have accepted them and consider the current name for the Calabar Python to be Charina reinhardti.  I am not a herpetologist so my views about the purpose of taxonomy are a bit closer to those of the earlier taxonomists - that is, a central purpose of the Linnean classification scheme that was to make order out of the previously haphazard and imprecise way of naming species.  The renaming of species that have had the same names for long periods of time may cause confusion, especially among people who aren't aware of the most recent taxonomic changes.  An excellent example of the confusion that taxonomic changes can lead to was also generated by Kluge after he concluded that the common Boa (Boa constrictor) and two species of boas found in Madagascar should be placed in the same genus, Boa.   The two Madagascar species were Dumeril's Boa (Acrantophis madagascarensis) and the Madagascar Tree Boa (Sanzinia madagascarensis).  Here's the problem - since Kluge placed all three species in the genus Boa, he was left with both Madagascar species having the same name (Boa madagascarensis).  There are only two ways to address this problem.  The first is to change the name of one species entirely as follows:

                       Old name                                                   New (scientific) name
Boa constrictor               Boa constrictor                             Boa constrictor
Dumeril's Boa                Acrantophis madagascarensis        Boa madagascarensis
Madagascar Tree Boa     Sanzinia madagascarensis             Boa mandrita

This creates a new species name, Boa mandrita, that bears no resemblance to its former name and is therefore rather confusing.
The second way to address this problem is to publish the paper with your findings but not change the names.  The information about the evolutionary relationships will then be in the literature where interested people will become aware of it, and the silly confusion caused by this type of name change will be avoided.  Whether Kluge's findings with Calabaria made it absolutely necessary to place this species in a new genus rather than allowing it to to retain its name (as a boa) is something that will have to be decided by herpetologist taxonomists.  For now, I'll stick with the genus Calabaria.  Regardless of the fate of the scientific name changes I will, of course, continue to use the common name, Calabar Python, rather than "Calabar Boa".  A common name is just that - a name that is commonly used by many people.  The common name certainly may change over time, but at this moment it remains the same and there is no reason to change it.

Natural history:  The Calabar Python is found in West Africa inhabiting areas of moist soil in forest environments.  It is a tubular snake with blunt tail and head.  It is generally described as a burrowing animal that preys on lizards and small rodents.  The method of defense employed by Calabars involves rolling up into a tight ball with its head in the center and the tail exposed.  The head is relatively featureless and if you are any distance from it, you quickly discover that it is virtually indistinguishable from the tail.  The eyes are small and the same brown color as the scales surrounding it; the mouth is not a visually distinct structure.  There is no apparent neck in the adults and the shape of the tail is identical to the head.  As an added "attractant" for the tail, almost all of these animals have random patches of white there that may serve to draw attention to that part of the exposed "ball".  At one time I believed that these white patches were found in all specimens, but I recently obtained a female that lacks any.  The balling defense has been used by all of the snakes I have kept, and there has never been the slightest sign of an intention to bite.  Wild caught animals reach a maximum of 3+ feet but it will be interesting to determine the size that captive born animals eventually reach.  The adults that I have seen are all patterned with brown and yellow scales.  Neonates have a reddish color rather than the yellow for about 1 year, after which, the reddish scales gradually fade to yellow.  I have recently been shown pictures of a WC adult that retained the reddish color.  These are not as common as the brown animals and whether they represent regional color morphs or simple variants is unknown.

Husbandry:  The following information is derived from my experience with three long-term wild caught (WC) animals and a CB neonate added several years ago.  The animals were all kept in one 20-gallon aquarium with a screen top.  Using wood and Plexiglas squares as platforms, I have made the cage tiered.  There is a heating pad under one end of the cage although the animals are never at that spot except in the days immediately following feeding.  I use paper to line the bottom of the cage.  A large, stable, water dish is kept in a corner.  The animals are kept in a room where the temperature remains approximately 75-80 F throughout the year.  These conditions appear to be satisfactory and there have no problems with disease or refusal to eat I noted, they appear to prefer the cooler area.  As noted below, however, there may be a requirement for a warmer area when animals are gravid.  I have never cooled the animals down and they have continued to eat during the entire year.  Many people also recommend keeping the humidity high.  I do not do this and have not seen any problems with shedding, although the sheds come off in several pieces.  In all the years that I have kept these animals, retained eye caps have occurred only once and were removed with the subsequent shed.  I feed live or frozen/thawed rodents - no larger than mouse "fuzzies" and have never had any problems with the animals eating.  I do not give them mice old enough to have open eyes.  The Calabars are almost lizard-like in their feeding - that is, they do not gape their mouths as wide as many other snake species do.  They are deliberate feeders and initiate eating by "probing" the feeder pups rather than striking.  They compress the food within their coils and against the sides and floors of the cage. 
    Their "personalities" and habits are quite interesting and lead to some unusual aspects in their husbandry.  They are prodigious eaters and the 20-25 large fuzzies given per feeding to the trio (generally once a week) are invariably gone the next morning.  Often, this is the result of one snake eating most of the food.  The next week another snake(s) will do the same and there has been no trouble in maintaining the animals in a single cage.  The only time they refuse food is during the late pre-shed period (they turn a milky blue gray at this point) and one or two days before egg laying (although one female ate some fuzzies on the morning of the day that she laid three eggs).  Their weight fluctuates between feedings to a much greater extent than any other species I have kept.   The intake of water is "record breaking" for their size.  The water dish has to be constantly refilled and I often see them drinking.  While they are supposed to primarily be a burrowing species, they are seen prowling during the day more often than any of the other species I maintain, especially when they are hungry.

    Breeding and egg incubation:  First, a quick note on the sexing of this species.  Probing is, of course, one method and Ross and Marzac list the probe depths of the sexes as 10-11 scales in the male, and 3 scales in the females.  It would appear that probing is not necessary, however, since only the males have noticeable spurs lateral to the anal scale.
    My original pair of Calabars has successfully bred for the last eight years and a newly acquired female bred the first year that she was in the group cage.  I would like to take credit for having come up with clever strategies to allow breeding, but the first clutch was a complete surprise.  Since then, the animal has produced clutches every year.  I have observed these animals mating at different times during the last three years.  Mating took place during a considerable range of months; October in 2004, and September through November during 2005.  Observations were always made when I turned the lights on some hours after the room had been completely dark:

Calabar pair mating with cloacas above hide area.
I happened upon this scene while checking on my animals in the evening after the lights were out in the snake room.  Soon after I took the picture, they had separated and went back into the hide area below.

The female laid eggs three to five months after mating. 
As the eggs develop internally, the female becomes swollen in the posterior third of the body.  When this becomes noticeable (see immediately below), I transfer it to a 10 gallon aquarium with a nesting box containing moist potting soil, and an under cage heater to provide more warmth. 

A gravid female Calabar contrasted with a male. The female has significantly wider girth in the center of her body.
Male (above) and gravid female (1-26-03).  Three eggs were laid 17 days after this picture was taken.

Another sign of gravidity is that the areas between the scales in the abdomen become readily visible:

Gravid female on the left (four eggs laid 45 days after picture); male at right.

Calabar eggs are extremely large in relation to the size of the adult female:

A clutch of three eggs laid on 4/13/2004.
  The thickness of the shell seems to vary from relatively thin walled and more flaccid than other snake eggs to thicker, turgid eggs.  Both thin and thick walled eggs have been viable.  Incubation temperatures of 82-84 F have been successful (46-56 days incubation) in the past although during the last few years there have been  increasing problems.  One attempt at incubating them at 76-78 F was not successful and 3 of 5 embryos died at 56 days of incubation.  The remaining two were opened and the relatively mature fetuses were successfully maintained out of the egg with heat and humidity (see Question 2 below).  In the following year, two of four eggs failed to hatch by day 52 and both eggs were slit.  I removed the heads from the membranes covering them and allowed the animals to continue maturing within the eggs.  They later emerged and were eating, shedding, and growing normally.  The eggs must be kept relatively dry (unlike other species that require a very wet substrate to prevent collapsing).  Maintaining Calabar eggs on a wet substrate may result in fungal invasion and destruction of the clutch.  Prior to 2003, the Calabar hatchlings ate readily, and in most instances had taken live mouse pinkies within two days of hatching.  Beginning in 2003, I have experienced increasing problems in getting them to accept food.  In that year, several weeks passed before they took their first food.  In 2004, only 2 of 4 eggs hatched and despite every strategy I could think of to get them to feed, both eventually died.  In 2005, 1 of 3 eggs hatched and the neonate did not accept any food.  Despite force-feeding it with Gerber Beef Baby Food sprinkled with Reptavite, as well as pinkies. the snake eventually died.  In 2006, there were a total of 7 eggs laid but none of them proved to be viable.  The reason for the increasing difficulty in hatching eggs and feeding the neonates remains elusive.  2007 proved to be a disaster.  Only the oldest female became gravid.  I had been thinking about "retiring" her but didn't with very unfortunate consequences.  She laid two eggs (both proved to be non-viable) and a third smaller egg became entangled in her oviduct which became prolapsed.  I removed the egg and cleaned her as best as I could.  I attempted to get the oviduct back into her body cavity bus was not successful.  Finally, I amputated the extruded oviduct under sterile conditions.  My attempts to remedy the situation were useless and she died the next day.
The reason for the increasing difficulty in hatching eggs and feeding the neonates remains elusive.  Having changed substrates for the eggs and monitored their incubation temperatures carefully, I am now assuming that the incubation of the eggs is not the cause of the problem.  A difference over time that I have not previously considered was the temperature of the gravid female.  If animals become gravid in the future I will attempt to give the animals greater access to heat during the pre-hatching period.  It is possible that the cage temps were too cool for development within the body of the snakes and the eggs were born with embryos not developed to the stage they should have been at.  If this was the case, the incubation time would have been prolonged (and it was) and the animals may have been born prematurely in terms of feeding response (and I have had to open many eggs in recent years or the animals would have died in ovo).  Hopefully, I will have an opportunity to test this idea in the future...
The neonates are red and brown changing to the more typical yellow or orange and brown as they grow.



    These are a series of questions that I have about the behavior of some of the snakes in the collection.  I don't have any definitive answers for them, just ideas.  If you know of references to material that may offer solutions or if you have any comments, let me know...
1.  Reason for non-breeding in WC animals.
I have successfully bred Calabar pythons - A wild caught (WC) male and female purchased in 1993 and 1994 respectively.  I housed them together and did nothing other than feed them regularly and offer large and necessary amounts of drinking water (details of care for this species are found above).  In 1998, the female became gravid and laid a clutch of normal eggs.  Every year since then, she has laid eggs.  I assumed that the four years between her arrival and the first clutch involved acclimation to the point where breeding could occur.  I also assumed that this acclimation was most important for the female for the following two reasons.  The first is that the production of eggs involves a great expenditure of energy (the clutches have been in the range of 30-40% of the female's pre-laying weight).  It therefore stands to reason that the stress of a novel environment would inhibit the female reproductive processes more than the male who only has to expend the energy required for a few ejaculates.  The second reason is rooted in male chauvinism - it's the female who always gets the "headache" while the male is raring to go…  A friend purchased a WC female two years ago.  On a whim, we placed it in with my pair.  Our only concern was that the presence of the new female might inhibit the breeding of my pair.  We were very surprised when both females laid clutches of eggs within one day of each other.  Is it therefore possible that the male is more reluctant to breed in a novel environment than the female?  The new female had to be receptive and she was in the USA less than a year before laying a clutch.  Perhaps, at least for some species, it is the male that fails to breed rather than a "non receptive" female.  The question, then, is whether the above assumption is correct, and if so, is it true for other species.

    On this topic, I would note that based on our original assumption, we placed some male Mandarin Rat Snakes that were WC in 1999 in with a captive bred female of sufficient size and age to breed.  The animals showed no signs of breeding and the female did not become gravid.
2.  Question re: yolk formation in non-gravid females.
Some years ago my viper boa gave birth to a large litter (23).  This is another species that is rarely
bred, and my breeding strategy was similar to the Calabars - put a male and female together and leave them alone.  She never bred again and subsequently the male died.  The following year after the male died, she proceeded to gain weight as she did when she was gravid - this species resembles a Gaboon Viper in being short (1 1/2 - 2 feet) and attaining a huge girth that virtually prevents it from coiling.  I was curious about the weight gain since there have been a fair number of reports of snakes apparently retaining sperm (or more likely, fertilized ova) across seasons and then giving birth in the absence of subsequent contact with a male.  She attained a weight of over 1 kg, and then stopped eating and began to lose weight.  Around this time I noticed small, hard, brown matter in the bedding.  I assumed that it was dried feces and simply cleaned the cage.  One day, I noted that three large egg masses - that is, yolk material floating in the water dish, and I realized that the brown material was dried yolk.  This past year, the identical thing happened with a Rainbow Boa kept by a friend and again, masses of yolk were deposited in the water dish.  This type of event raises a number of questions: Why does an ovoviviparous animal pass quantities of yolk rather than conserving energy by re-absorption?  Does this ever occur in the wild or is this phenomenon simply a result of excellent availability of food?  How common is this phenomenon in captive animals?
3.  What are "slugs" (infertile eggs).
    Snakes sometimes lay slugs.  These are soft, thin walled "slippery" eggs that succumb to fungus very rapidly.  The only reference to this phenomenon that I have found is a single note referring to them as infertile.  I very much doubt that there is any hard evidence for this - just an assumption that since the eggs never produce hatchlings, they must be infertile.  If this assumption is correct, I wonder what the mechanism would be that "signals" the female not to bother depositing a normal (thick) layer of calcium on the exterior of the egg.  It would have to be a signal that regulates shell formation and relies on fertility as the trigger.  The developmental stage of corn snake and ball python embryos at the time of laying appears to be somewhat similar to a 48-72 hour chick embryo.  While in the mother, therefore, the embryo is very small and immature.  How would such an embryo produce enough "signal" to affect shell deposition?  An equally (or more) attractive hypothesis would be that the slugs are fertilized eggs that are laid prematurely, possibly as a result of stress.  My black milk snake (Lampropeltis triangulum gaigiae) female once produced 12 full-size slugs.  She mated with the male on numerous occasions, so unless one of the pair is infertile, the eggs were fertilized.  Why then, did she lay these slugs?  In retrospect, I may not have provided an adequate nesting box.  Could this factor (and possibly others) have induced stress that was involved in the production of slugs?  If stress is a factor, there is again the problem of signals.  In this case, however, one could postulate hormonal imbalance induced by stress chemicals.

4.  The question of double clutches.
    A number of snake species "double clutch" - that is, they lay an initial clutch of eggs, and then after a suitable interval, they lay another clutch (no male being introduced between laying).  Very often (in my collection anyway) the second clutch is not nearly as viable as the first - many slugs and few viable eggs.  My anerythristic corn snake laid 20+ viable eggs and then followed with a second clutch of 10 slugs and one thin-shelled egg.  What is the mechanism of double clutching?  I would assume that fertilized (or unfertilized) ova are in some sort of metabolic and developmental stasis.  Is this phenomena dependent upon abundant food between the clutches?  Is this something that only happens in captivity - in fact, has it been bred into captive animals the same way that we have bred chickens that lay an egg(s) every day?

5.  Fecundity issues.
    I worked with a group of 11 Mexican Milksnakes (Lampropeltis triangulum annulata).  I bred the eight females with the three males in an ordered fashion.  I waited two or three days before using the males after a previous breeding.  All females were bred 3 or 4 times.  In all instances, copulation was observed.  The end results were: one snake laid slugs; one snake laid slugs and viable eggs; one snake laid eight viable eggs; and five snakes never showed signs of being gravid.  The question I have concerns the "whys" of non laying.  Are the males incapable of breeding as often as we thought they would be?  Are the females differing in their fertility?  The statement "proven breeders" appears on commercial lists of snakes for sale.  I wonder if this is an indication that the successful breeding of these animals may be less common than I thought.

6.  Mating behavior.
    When some male and female snakes are put together for breeding, there is a characteristic twitching on the part of the males (and to a lesser extent, the females).  This behavior occurs in all of the Colubrid species I have observed.  What is the reason for this twitching?  It is the only time that I have observed this behavior.  I can find nothing in the literature concerning this phenomenon except for simple description.  This does not occur before or after the breeding season.  It may not occur when two males are put together during breeding season.  In the case of two male Honduran Milk Snakes (Lampropeltis triangulum hondurensis), in cages adjacent to a receptive female, they simply bit each other when placed in the same cage.

7.  Temporary color change in adult Calabars.
    On November 27, 2002 I weighed and examined my Calabars as part of my husbandry routine.  At that time, they all appeared to have normal coloration.  On December 13 I examined the animals and noted that the female F1 was in the midst of shedding and seemed to have developed a striking color change in the dorsal scales of the first third of her body as well as some white scales on the top of the head (see picture on left immediately below).  I assisted her in shedding and it became apparent that the color change was not the result of retained shed - areas that I helped remove the shed from had little discoloration, while the major areas of discoloration had not retained the shed.  Six weeks later (Jan. 16), the discoloration was still present although greatly reduced (see picture on right immediately below).  There were no signs of additional shedding in the areas that had lightened.  The behavior of the animal appeared normal and there was no loss of weight.  At the time of the second picture, the animal was gravid and she laid three eggs on February 12.  She ate approximately 20 fuzzies on February 13, and in terms of behavior, appeared to be perfectly normal.  Neither of the other two Calabars (1.1) in the same cage showed any sign of color alteration.  By March, she had lost all signs of the color change. The questions are obvious: What is the nature of a color change with such a rapid onset, and what induced it.

           12-13-02                                                          1-16-03


As a scientist I know that solving biological problems is not a simple process of finding the one absolutely correct solution to the problem at hand.  Based on the evidence I have gathered to date, however, the following are tentative answers to two questions originally asked above.  Like every answer in science, it remains open to changes resulting from new information and/or observations.  But for now, the evidence indicates the conclusions given below:
1.  Question re: Raising snakes outside the egg.
    The following experiences appear to provide evidence pertinent to a question about the possibility of raising late stage snake fetuses outside the egg:

    Until 2001, We had been using an incubator that kept eggs at a constant 82F.  In 2001, the incubator did not function and the eggs were kept at about 78F at a friend's home.  The five Calabar eggs (from the two females) were a week slow to hatch - and then two of them began to rot.  He noted that the other three looked good, and so decided to wait another day in the hope that they would hatch.  This did not happen and another egg went bad.  At this point John decided that having nothing to lose he would open the two remaining viable eggs (this was on June 11).  He did so and had two animals that looked and acted moribund.  When he first showed them to me, the weaker one was limp, on its back, and had a gaping mouth.  I picked it up looked at its motionless body and pronounced it dead (I am a toxicologist and usually capable of identifying "dead").  John agreed, and we got some formalin to preserve it.  At this point the snake twitched its tail a few millimeters.  Being highly trained and observant biologists, we assumed that the snake was not dead and we put away the formalin.  The two animals continued to look and act the same way for about a week.  John thought that they were dead on numerous occasions, but invariably they would twitch or close their mouth.  From that point on they began to look and act more normal with each passing day.  They took their first food on June 23(!).  Over the next few months they became indistinguishable from normally hatched neonates.  They shed, ate regularly, and prowled (often) when they were hungry.  Is it possible, therefore, that contrary to herpetoculture lore, it is possible (at least in some instances) for snake embryos to develop ex ovo (as long as they're close to hatching).  Their "behavior" - the limp appearance and intermittent twitching mirrors near hatching behavior while in the egg."  In 2002, 4 eggs were laid on March 6.  The eggs were incubated under inadequate conditions (in a glass bowl with a light bulb heat source placed above) and the temperature varied from 76- 90.  On April 25 the uppermost egg pipped.  I slit a 2nd egg since there was movement in it.  On April 27 I slit the remaining two eggs since I felt that not doing so would result in the fetuses' death.  One egg in particular, had an immature fetus that was motionless and more lightly colored than normal (pink and brown vs. red and brown).  On May 1 the third neonate emerged and on May 11 the last neonate left the egg.  This last neonate was still noticeably lighter than its clutch mates and did not eat for 1-2 weeks.  By May 28, all neonates were eating normally and there growth has been typical for the Calabar neonates that I have had in the past.  It therefore appears that, at least for Calabar Pythons, eggs may be slit prior to hatching and still result in viable hatchlings.
2.  Question of possible 11-month reproductive cycle in Calabar Pythons.
Over the last five years I have noticed an interesting deviation from this pattern regarding the breeding period of my Calabar Pythons.  The dates that my F1 female has laid eggs are:

1998 - 6/24
1999 - 6/17
2000 - 5/18
2001 - 4/15
2002 - 3/9
2003 - 2/12

2004 - 4/1
2005 - 3/10
With the exception of 1998-1999, there was a consistent 11-month cycle over a 5-year period - 11 months between one egg laying and the next.  This pattern broke down in 2004, however, and it therefore very possible that the "11-month cycle" was simply a statistical oddity.

3.  Mechanism of the resistance to fungal infection present in snake eggs.
Snake eggs are highly resistant to fungal invasion.  One of the ways that dead eggs are first identified is by observing fungal growth.  As long as an egg is viable there is little or no fungal growth.  The following is a picture of three connected ball python eggs:

The two on the outside are dead and covered with brown fungus.  The egg that is sandwiched between these two is white and fungus free.  I had wondered what the mechanism for snake eggs' anti fungal properties was  If it is the eggshell that prevents fungal attack, what would the mechanism for doing this be?  Is an eggshell change in fungal permeability due to embryonic death?  If that is so, what is the mechanism that allows the eggshell to become permeable to fungal attack?  What comes first - a dead embryo or the fungal invasion of the egg?  If it is the dead embryo, as I suspect, how does the viable embryo keep the fungus out - how does it maintain the egg shell barrier if this is the primary mechanism for fungal resistance?  I can't consider this question really solved because I have no experimental evidence to support it, but a suggestion was made that I think had merit.  Someone wrote and suggested that the viability (or lack of) would change the temperature and it was this temperature change that allowed the fungus to grow.    


Viper Boa:

Animals were observed copulating in water once during April.  Female gave birth Oct. 11.  There were 23 live and 2 dead.  Birth was not observed.

Attempts to feed with pinkies, unscented pinkies, and pinkies scented with salamander slime were unsuccessful.  A small number of animals did eat pinkies scented with a leopard frog.  The neonates were maintained in small containers partly filled with wet sphagnum moss and a dry area.  The animals appeared to have remained exclusively in the moss.  All non-eating neonates were force-fed with macerated pinkies through a syringe.  The response to this strategy was strange in that the neonates lost most of the intubated weight between feeding (at one week intervals).  In the end, only 2 neonates survived.

Calabar Python

Calabar burrowing python with clutch of eggs - 1999
The Calabar in 2000 with her clutch of three eggs.


6/24 - Female laid 3 eggs weighing a total of 181.2g.  The pre-laying wt of female was 376.9g.  Eggs were therefore 48% of pre-laying body weight.  Eggs were kept at 84 F on relatively dry vermiculite as per suggestion of VPI.
8/10 - 8/13  Two of the eggs hatched.  The animal in the third egg died in ovo (movement in the egg was noted on 8/10 so I assume that the animal could not slit the egg).
8/13-8/14 - Both hatchlings ate live pinkies.

June - 1st week - Noted female appeared swollen in posterior third of body.  Finding confirmed in subsequent days.
6/13 - Female moved to nesting box with dampened peat moss. Animal was restless for several days and finally settled in box.  Temperature was adjusted so that heat was 82-83 F.
6/17 - 9:00 a.m. one egg found.  The egg was smaller than last year and very thin shelled.  Egg left in situ and cage returned to shelf.  It was non-viable and later discarded.
          3:00 p.m. two more eggs found.  These eggs were full size and normal looking.  The peat moss and inside of the nesting box was dampened considerably.
6/19 - Eggs moved to environment kept at 84 F and placed in glass dish with vermiculite.
8/3 - 48 days post-laying.  Both eggs slit.
8/5 - Both snakes emerged.  The first weighed 38.2g, the second 41.5g.  The second had a slight kink in the neck area immediately behind the head.  After 2-3 months, the kink was no longer present.   


April, 4th week - Noted female appeared swollen in posterior third of body.  Finding confirmed in subsequent days.
5/16 - Female placed in nesting box with moist potting soil.
5/18 - Three eggs laid.  Weights of eggs - 73.2; 61.4; and 66.3g.
7/3 - 47 days post-laying.  Two eggs were slit.
7/5 - Heads appeared.
7/10 - Two snakes emerged.
7/11 - Third snake emerged.   


4/13 - Both females placed in nesting boxes; F1 did not appear to be very swollen although there was some separation of the scales in her posterior region; F2 appeared gravid.
4/15 - F1 laid three eggs in morning.  F2 laid two eggs in the afternoon.  Eggs were kept at 76-78 F.
6/10 - (d59) 2 eggs go bad.
6/11 - one more egg goes bad; remaining two opened and large, immature neonates removed.  One is left with yolk sac attached for one day.  Animals appeared moribund but were still alive and showing intermittent activity (especially when touched).
6/15 - Both neonates still alive(!)
Gradually the neonates gained strength and began to eat, grow, and behave normally in every respect.
3/6 - F1 laid 4 eggs in the group cage.  The eggs were stuck together and I did not attempt to separate them.  They were placed in a covered glass dish on lightly moistened vermiculite.  Lamps with 40-watt bulbs were situated above the dish until an appropriate temperature reading was reached as noted on a temperature probe placed within the dish.  I later learned that the actual temperature within the dish varied significantly from point to point and it may have ranged from 76- 90.
The weight of the clutch was 291g and the post-laying weight of female was 504g.  The eggs were therefore approximately 37% of total weight of the gravid animal.
3/9 - The two uppermost eggs appeared somewhat collapsed.  Strips of paper towels were used as wicks for water by placing one end on the eggs and the other in a container with water.
4/25 - In the evening between 8:00 and 10:00 P.M. the uppermost, collapsed egg pipped.  I slit the 2nd collapsed egg since there was movement in it.
4/26 - I elongated the slit for the length of the 2nd egg.  The neonate was out of the yolk sac and had good color (bright red flecks).
4/27 - In the morning I made a 3/4” slit in the more collapsed of the two remaining untouched eggs (the 3rd).  A small amount of clear fluid extruded.  In the afternoon I elongated the slit for the length of the egg.  The snake appeared to have good color and was free of the yolk sac.  The head was outside the egg late afternoon.
4/28 – The 3rd neonate was “blowing bubbles" for the entire day.  I slit the 4th egg down its length.  This fetus was more immature than the others and had a pink rather than a red coloration against the brown.  A considerable amount of fluid was extruded.  The head was dorsal and I freed it from the overlying membrane.  The egg was partially “re-closed” with a hemostat.
4/29 - Neonates 1 and 2 left their eggs and were placed in a cage with heater beneath and a 40-watt bulb on timer as a daytime heat source.
5/1 - 3rd neonate emerged.  It still had some yolk sac left.  I placed it into the same cage as the others.  The fetus in the 4th egg is not noticeably moving.  Its head is above the egg and exposed to the air.
5/11 – 4th neonate emerged from egg.  It was noticeably lighter red than the others at hatching and did not eat for 1-2 wks.
5/28 - all neonates were eating well and growing.   

2/12 - F1 laid 3 eggs in nesting box.  Eggs placed in incubator at 84 and 90% humidity.
3/31 - F2 laid 4 eggs in nesting box.  Eggs placed in incubator at 82 and 90% humidity.
4/8 - F1 clutch: (d55) I slit the two flaccid eggs on top with an approximately 1cm cut.  There was no leakage of yolk.
4/11 - Hatchlings pipped in the egg that had not been slit and one of the slit eggs.  There was movement in the other egg.
4/12 - Neonate emerged from "non-slit" egg and placed in cage (wt. 36.6g); third hatchling pipped.
4/14 - Remaining two neonates emerged from eggs and placed in cages.  The weights were 39.4 and 37.7g.
5/6 - Discarded egg that was shriveled and had mold growing on it.  It was the uppermost egg and had collapsed to a greater degree than the other eggs.

5/16 - Two eggs slit - movement was detected in both eggs.
5/18-19 - Neonates emerged.
Neonates did not begin to eat until 3-4 weeks after hatching. 

4/1 - F1 laid 4 eggs in nesting box.  Egg-shells appeared to be thinner than normal.  Eggs placed in incubator at
84 and 94% humidity.
4/10 - Eggs were becoming wet with leaking yolk.  Fungus set in and eggs were discarded.
4/13 - F2 laid 3 eggs in nesting box.  Eggs appeared to be normal and shells were firm.  Weights of the three eggs were A- 72.1g; B- 72.5g.; and C- 78.2g.  The eggs remained turgid throughout the incubation period.
6/7 - Egg "C" pipped (56 days after laying).
6/8 - Egg "A" pipped.
6/9 - Egg "B" pipped.
The neonates refused to eat despite the various strategies I employed including scenting with rats, mice, gerbils, hamsters, Guinea Pigs, chinchillas, and rabbits; feeding live or dead pinkies; exposing brain matter of a dead pinkie; and shipping the animals to a knowledgeable friend in the hopes that a change of locale might be the answer.  Similar to my experience, nothing worked for him and the neonates died on October 31 and November 3.  I should have attempted to force feed but this is a skill that I have not mastered and the Calabars may prove to be difficult subjects as their mouths do not gape to the same extent as other species.

10/16/2004 - Male and F2 copulating.
3/17/2005 - F2 laid 3 eggs.  They were smooth and shiny at first, but solidified during the next few hours.
3/30 - One egg is bad and discarded.
5/7 - One egg pipped. 
5/9 - Remaining egg slit - fetus was dead.
5/11 - Neonate left the egg - wt 41.9g.
5/13, 5/19, 6/2 - live pinkies offered and not eaten.
6/8 - Force-fed with liquefied pinkies through syringe - 0.8 ml given and retained.
6/22 - Pinkies offered and not eaten.
6/27 - Force-fed similar to 6/8.
6/27 - 12/9 - Snake refused numerous offers of pinkies, including scented animals.  It was force-fed repeatedly but slowly lost weight and died on 12/9.

7/29 - 11/7/2005 - Animals were repeatedly seen mating at night after lights in room had been turned off.
1/13/2006 - Females moved to cages with nesting boxes containing moist sphagnum moss.
2/10 - F2 laid 3 eggs weighing a total of 246.7g.  Eggs put in incubator at
82 and 91% humidity.  The eggs were placed in glass dishes on moistened perlite.
2/21 - 2/25 - F1 stayed on portion of cage over heat pad - not in nesting box.
2/25 - F1 laid 4 eggs (on heat pad area).   Eggs appeared to be o.k. and were handled as F1's.
3/1 - 1 F2 egg dead, discarded.
By April, all eggs had proven to be non-viable and were discarded.

3/12 - F1 laid 3 soft-shelled non-viable eggs, 1 caught in oviduct.
3/13 - After placing female in warm water and attempting to palpate egg free, I slit the egg and removed it.  When I came back into the room, later I noted her oviduct prolapsed and shriveled.  After two days I cut the extruded part of the oviduct.  There was no bleeding and the remainder of the oviduct was withdrawn into the cloaca, but nevertheless, she died the next day.

Rainbow Boa:

7/1 - 9/20/01 - The animals were repeatedly observed mating.
3/9/02 - Female gave birth to 23 babies.  There were also 2 slugs and one dead (the smallest of the litter).  This indicates a gestation period in the order of 7-9 months.  Most of the babies began eating dead pinkies a day after being born and all had eaten within two weeks of hatching.  


7/7/02 - Animals observed mating (while in water bowl with tails elevated).

Animals observed mating but female has shown no sign of gravidity.  Female eventually "gave birth" to a series of slugs and one partially formed embryo.


Corn Snake:

4/10+ - The male and female placed together.
8/10 - eggs laid.
10/10-10/13 - Snakes hatched.   


5/18-5/28 - Animals paired and placed together.
6/20 - F1 laid 17 eggs, of which 6 were viable.
8/18-19 - F2 laid 20+ eggs, all of which appeared to be viable.

3/14-5/1 - Animals bred.
8/12-8/13 - F3 laid 10 eggs.
Since there was a mite infestation that included the Corn Snakes, the eggs were not placed at 84 F but remained at ambient temperature (approx. 70-75 F). 12/5 - 4 snakes began to emerge (113 days after laying).  The remainder of the eggs were placed in warmer room (83 F), became moldy, and were discarded.

7/13 - F1 laid 6 eggs.
9/7+ - 4 eggs hatched. 

4/8-4/25 - Animals bred.
6/23 - F4 laid 13 eggs.
7/2 - F1 laid 8 eggs. 

4/7-4/22 - Animals bred.
5/13 - F2 laid 23 eggs, wt 189.5g
5/21 - F1 laid 3 viable eggs weighing 22.2 g.
F(2) not bred.  Animals refused food from 4/19 - June 10..  She laid small slugs on 6/4 (2), 6/5 (1), and 6/11 (13).  4 apparently viable eggs were also laid on 6/11.  Eggs were incubated at 82 F but developed fungus and were discarded.


Gray Banded Kingsnake:

5/4-5/12 - Animals bred
7/26-29 - 3 slugs laid.
4/8-4/14 - Animals bred.
6/12 - Laid 3 eggs.  Eggs incubated at 79-80; 98% humidity.  The eggs were not viable.
4/24; 4/26; 4/27; 5/4; 5/7; 5/20; 5/24; 5/27; 6/4; 6/6 – mated.  Successful matings were observed from
4/24 through 5/24.
7/11 - Laid 4 slugs.
7/24 - Laid 2 slugs.

4/26-5/21 - successful matings.
7/20 - Laid 4 eggs, 1 good(?), 3 slugs.
8/6 - Laid 4 eggs, 2 good, 2 slugs.
Eggs incubated at 82, 96% humidity.  The eggs were not viable.

Mexican Milk Snake:

4/9-5/6 - Animals bred.
6/23 - Several dried eggs discovered. 

4/12-4/21 - Animals bred.
6/20 - Laid 8 eggs(!).  Wt. 210.4 g, which was 40% of the pre-laying weight (348.2 g.).
8/29-8/30 - Hatching took place.

4/24; 4/26; 4/27 – Animals mated.
8/2 - Laid 1 egg.
During the second week of August it became apparent that she was egg bound.  Palpation did not move the eggs and in late August she was given to a veterinarian who surgically removed the (6) remaining eggs.
10/4 - Normal neonate found hatched.

Black Milk Snake:

Animals bred on the following days - 4/8, 4/12, 4/14, 4/22 - No interest seen except for male.
5/4 - 5/6 Mating appears to have taken place.
5/11 - After male was extremely restless, I put female in cage.  Courtship immediately began, and bedding moved by morning.
No eggs were subsequently laid. 

4/21 - Lined up and appeared successful; mating continued in the afternoon and the morning of 4/22.
4/24 - Lined up and mating.
4/27 - Mated.
5/21 - Placed in cage 5:00 PM; removed next morning; appeared to be mating.
5/27 - Nesting box placed in cage.
6/15 - New nesting box that is opaque and covered placed in cage.
6/18 - Laid 10 large slugs.  Female wt. 718.4 g, which was 27% of the pre-laying weight (978.7 g).

Sinaloan Milk Snake:

Animals bred on the following days - 3/15; 3/21; 3/28; 3/29; 4/26; 4/30; 5/8-9; 5/12; and 5/15.  Activity was intermittent.  Positive mating occurred on 4/30.
Female ate at various times through 7/3.
7/20-21 - 10 eggs laid in nesting box that contained sphagnum moss and peat moss (relatively dry).
7/22 - Eggs weighed 123.5g (female weighed  344.5g).  Eggs 36% of pre-laying body weight.
7/27 - Eggs weighed 123.8g.  Those on top were collapsed to some extent.
7/29 - Eggs weighed 125.0g.  Eggs appeared unchanged.
7/31 - 126.0
8/18 - Eggs appeared unchanged.
9/10 - 146.7
9/17 - Hatching begins (59 days): 4 snakes pipped
9/18 - 3 snakes out of egg
9/19 A.M. - A total of 7 snakes out of egg.  2 pipped.  1 egg (uppermost one) slit with razor.  This egg is full, movement detected.
9/19 P.M. - 2 pipped snakes in morning left eggs.
9/21 - Pinkies given to all 9 snakes.
9/22 - 4 snakes ate
9/23 - Remaining egg slit by snake (away from slit that I placed in egg)

Male removed from brumination on 3/19
Animals bred on the following days - 4/18; 4/23; 4/30; 5/4; 5/195/27; 6/6; 6/12; and 6/18.  Activity was intermittent.  Positive mating occurred on 5/27, 6/6, and possibly 6/11.
Female ate at various times through 6/14.
7/1 - 8 eggs laid in nesting box that contained peat moss (relatively dry).
8/26-29 - 7 eggs hatched (57-60 days)

4/8, 4/12, 4/22, 5/4 - No real interest shown by either animal.
5/9-11 - Nothing observed, but bedding was moved.
5/14-5/19 - Mating appears to be taking place.
5/29 - Active (I placed them together since the male refused food and was prowling)
7/10 - 8 eggs laid.  Weight of clutch was 102.1g.
9/6 - Hatching (58 days) 

4/15 - female appears receptive (tail raised); male interested.  No intromission observed
4/21 - attempting to mate and appear successful.
4/24 - (male pre-shed)
4/28 - attempted for a while (removed 4/29)
5/2 - attempted to mate
5/6 - attempted to mate; appeared to be successful
5/11 - great activity - not observed for long period of time
5/14 - activity, appears to be successful
5/18 - placed with male in morning; removed morning of 5/19
5/21 - placed in cage during A.M., appeared to mate.  wt of female 444.1g.
6/8 - placed in cage with male; no activity; given nesting box
6/17 - laid 10 good eggs.  Wt of female is 246.1; wt of eggs 137.9 (36% of female's pre-laying weight)
[Note: eggs incubated at 79-80; 98% humidity.]
8/23-8/29 11 snakes emerged (I may erred in counting the eggs, or there may have been a twin hatching although none the neonates were especially small). (68 days)


5/20 and 5/24 – Animals mated.  There were numerous additional matings with intromission observed.  No eggs were laid.
4/3 - 6/3 - Animals were mated but female showed no interest and was usually agitated.  Intromission was not observed and no eggs were laid.

Mountain Kingsnake:

Animals bred on the following days - 4/8 (male pre-shed), 4/14, 4/18 (male showed twitching behavior), 5/4, 5/13-14, 5/29 - interest seen except for very intermittent attention from male.  Female not receptive and was burrowing during the earlier days.
4/21 - Activity but I didn't observe for any length of time.
4/24 - Female pre-shed.
4/29 - Female shed; male pre-shed.
5/2 - Not observed.
5/6 - No interest.
5/21 - No interest.
6/1 - Observed for 2 hours - no activity.

4/4 - Some activity (mostly on the part of the female).
4/14 - Very interested; male trying; appeared to be tied.
4/18 - Initial activity.
4/24 – Animals attem
pted to mate, may have been successful
4/26-6/4 – Animals repeatedly placed together but no mating or activity observed immediately after being placed together.
No eggs were laid.
4/3-4/18 - Animals mated and appeared to be successful on several occasions.
No eggs were laid.

3/19-4/30 - Similar experiences as that of 2003.

The female escaped from her cage during November, 2004 and reappeared in March, 2005.  She appeared to be in good condition although obviously thirsty.  Normally, she begins eating in June, but this year, her "emergence from brumination" has been delayed and she has eaten only sporadically through the month.  Nevertheless...
6/23 - Female placed with male.  Male showed twitching behavior and attempted to track female.

Mandarin Rat Snake:

4/3-4/11 - Animals placed together.  Female twitched but male was "frantic" and showed no interest in mating.

3/19-4/1 - Animals placed together, male twitched occasionally, female showed no interest.  Not surprisingly, no eggs were laid.

2/7 - Female placed in cage with male.  There did not appear to be any interest shown by either animal towards the other at any point after that.  A friend and I were, in fact, wondering if we had a pair, and had decided to have the animals probed.  Then...
6/22 - 5 eggs were discovered in cage(!).  The eggs were somewhat collapsed and one has a yellow color and appears to be non-viable.  The eggs were all placed on moist vermiculite in a covered glass bowl to ensure maximum humidity.  A week after laying, the eggs seem to have filled out somewhat and there is no sign of fungus.
7/15 - 2 eggs were discarded as they were collapsed and clearly non-viable.  The two eggs were the yellowish one and the one that was initially the most collapsed.  The remaining three eggs were fully filled out, white, and apparently viable.
8/12 - All three eggs had hatched and the neonates appeared to be healthy.  2 neonates ate (live pinkies) after first shed.  The third neonate was force-fed Gerber's Beef Baby Food in 1ml amounts with no problems and there was some weight gain.   It refused food and eventually died.

5/30-6/10 - 5 eggs laid on different days.  Only 1 egg appeared to be normal, all of the others were slugs.  Three had been discarded by 6/15 and one soft shelled egg was kept since no fungus had appeared as yet.  The female did not appear to be done laying (her ventrum was not "hollow") and I left her in a 10 gal. aquarium with a nesting box.  Soft shelled egg was subsequently discarded.
7/25 - Egg hatched, neonate found in incubator.
8/10 - Neonate refused food, died.  My assumption is that it was not normal at hatching.


No activity noted and no eggs laid.

From time to time I note questions concerning methods to keep records about the status of the animals they keep.  There appears to be a number of computer programs that are designed to record husbandry records for snakes and other herps.  While the format of these programs may be satisfactory for many people, I prefer a simpler approach that allows me to easily keep track of only the key data that I collect without the necessity of a computer.  I have developed a simple system using data sheets and I have found that it works well for my needs. 
This form was made on an old and now defunct version of Lotus Freelance but I'm certain that it can be generated by numerous other current programs.  It is on an ordinary 8 1/2" X 11" sheet of paper and is designed to record a maximum of critical information with a minimum of fuss.  The most critical events that I keep track of are feeding and weight since these factors are central to the health of the animals.  The design of the form allows for two feeding events on one side of a 2-sided page for a total of four feedings on a single page.  The food is characterized (by eye) as a series of rodent sizes from pinkie (P) to adult mouse (M) or rat (R).  The size divisions are P(inkie),  F(uzzie), H(opper) , and adult.  I tend to further subdivide the types as, e.g., large pinkies (LP) (a full day after birth), large fuzzies (LF) (fuzzies where the fur is just becoming white), small hoppers (SH) (active neonates with eyes just opening), etc.  The type of food, number given, and number eaten are recorded.  Approximately once a month I weigh all the animals since I find weight is an extremely good indicator of general health, and these data are recorded in the "wt" column.  There is some space for notes and while many items can fit in the space (e.g. pre-shed, shed, or cleaned cage (cc)) the space will often have an asterisk in it referring to longer notes that are placed at the bottom of the page.  An actual sheet used recently is shown below:

8 X 11 form to track status of animals.

It contains feeding data, shedding information, weights, and a note describing an observation made on one of the animals.  I store the data in standard 3-ring notebooks and the format can easily be changed to reflect changes in the collection.

My e-mail address is