Winter is naptime for some reptiles and amphibians

Reptile and amphibian supervisor Bradley Lawrence guest-blogs on taking care of our diverse collection during hibernation months.

Reptile and amphibian supervisor Bradley Lawrence

Another North Texas winter is in full frigid effect — which means I layer on my warmest clothes, boots, gloves, scarves and – yes – my big, fluffy hat to keep warm. But for our reptiles and amphibians, when the temperatures drop, so do their body temperature, heart rate and digestion.

In the wild, these guys would need to find a temporary home underground or in a sheltered area where they can protect themselves and go into hibernation. Here at the Zoo, even though our reptiles and amphibians are in climate-controlled homes, we still need to take them through the motions of winter. Seasonal changes like temperature and rainfall are crucial cues to let them know when it’s time to reproduce.

Amphibians typically will lay eggs during rain events. This ensures that the eggs and tadpoles will have enough water to last through metamorphosis. Many temperate reptiles will take advantage of warm months to feed while resources are abundant, then go through a period of hibernation through the winter months. Some reptiles will breed prior to hibernation, then gestate through winter and lay eggs or give birth in the spring. Some reptiles will breed in the spring following hibernation.

At the Zoo, we have a “hibernaculum” that we use to house and carefully control the winter temperatures for those temperate animals that need a period of hibernation.  We start by gradually lowering the temperature of the animal’s enclosure and reducing the amount of food they receive. Reptiles generally need warm weather to digest food properly.

Texas horned lizard/Dallas Zoo

Once they have reached a low temperature, they’re taken off of food to let their bodies completely digest and process the food already in their system. Then, after a veterinary exam to ensure they are healthy enough to hibernate, they are placed in the “hibernaculum.” Here, the temperature for some of our snakes can be taken down to as low as 45 degrees.

The Texas horned lizard, a very high-profile lizard in our collection, is one reptile that requires a period of hibernation in order to reproduce. They are all in the hibernaculum now at about 49 degrees. We’ll slowly raise the temps in March to bring them out of hibernation. Then the males and females will be put together for breeding, helping to ensure the survival of this iconic Texas species.