Jansenii / Oxycephalum

Care Sheet


 by Freight Freitas

In general, both Gonyosoma species have the ability to reproduce all year long. In the wild it is believed that mating is stimulated by the rainy season from November to March. In their natural habitats G. oxycephala is known to produce up to four clutches of eggs per year, while G. janseni appears to only produce one clutch per year. This has not been the case with my captive snakes, as both species appear able to produce eggs multiple times per year. Some keepers have attempted to simulate the rainy season in captivity and believe that this has been the key to reproductive success, where I simply spray my snakes once daily throughout the entire year and have had high reproduction rates year round. I personally believe that it is the overall condition of the snakes, the captive habitat they are provided, and the way in which the keeper interacts with them that all factor into reproductive success. If the animals are housed well, allowed solitude from intrusion, and are cared for with dignity and respect they will then be content, and should carry out life activities in accordance with their genetic programming.

Copulation can last for several hours, and if such activity is witnessed it is best to slowly leave the area to provide the snakes the privacy necessary for complete exchange of genetic materials. If mating does result in the formation of eggs, the female should eventually begin to look a bit bloated in the last 3rd of her body just prior to the vent during the last few weeks of gestation. There is the possibility that the eggs will be thin and highly elongate, and may not be easily seen throughout the entire gestation period, which is generally from 50-70 days. Manual palpation can be performed to detect eggs within the female by running your fingers down the female’s abdomen while exerting light pressure upward into the abdominal cavity. If eggs are present they should each feel like a long mass with a space present between each egg. Your finger should literally go for a roller coaster ride along the female’s abdomen, only here the hills are eggs, and the valleys are short spaces between the eggs.

If the female is known to be gravid she should be fed heavily throughout the gestation period. Females normally tend to eat better than males when not gravid, so two appropriate sized food items per week should be sufficient. A typical adult female G. oxycephala approximately 6ft long and of normal body weight can easily eat two adult or jumbo sized mice per week, depending on her individual size preference. If a gravid female will accept more than two food items she should have it, provided she is able to fully digest the meal. Partially digested food items are generally a sign of overfeeding, as the digestive system can only fully digest a certain amount of food at one time, so use caution and common sense when increasing the females dietary intake during gestation. Most Gonyosoma will only eat a specific amount at any given feeding, and it is possible that a gravid female will not take any more food than she is used to. This means that she makes the final decision in dietary increase, and all you can do is provide her with options.

Though my snakes have been quite prolific I have only been witness to a few of the many matings that have taken place. My c/h female green G. oxycephala, and c/b black male G. janseni pair that produce the oxy-jansen hybrids typically mate high in their branches. These snakes are usually calm and comfortable with my presence, and have never discontinued copulation from a brief interruption. I have always made it a point to leave the room immediately, yet slowly when the pair is mating to avoid unnecessary stress and disruption. To date this female has laid a maximum of four clutches per year, with 4-5 eggs per clutch. I believe that some of my other pairs actually mate on the ground while hiding, and others may mate in the open when no one is home. Gonyosoma tend to be very private snakes, so it is no surprise that they will find a time to mate when they will be undisturbed.