In many vertebrates, including reptiles, after breeding there is a "refractoriness" to light and temperature stimulation. In other words, under conditions of light or temperature that would normally stimulate the reproductive system no stimulation occurs. A period of short days or cold temperatures is required to break this refractoriness and regain sensitivity to the conditions of light or temperature that will stimulate the reproductive system. In Gila monsters, this can be accomplished by holding them at cold and dark conditions in the winter.

Most recommendations involve a three-month cooling period with temperatures in the mid 50’s. Hibernation is begun by slowly decreasing the temperature until the final cooling temperature is reached.

With my breeding colony I suspend feeding at least two weeks prior to cooling. This allows the Gilas to fully digest their last meal before winter cooling. Beginning the first of December, my animals are slowly cooled and then maintained at a temperature of 53-57 F. On the first of March, the temperatures are slowly returned to normal. I don’t believe it is critical how slowly the temperatures are changed.

Water should be available during hibernation both for drinking and to increase the humidity of their hibernating environment. Provide it in a container that can’t be easily tipped over. I feel it is important to provide adequate humidity during hibernation to prevent dehydration of the animals.

For a complete description of the breeding protocol used with great success by Dr. Seward, see the second edition of Dr. Mark Seward's Gila Monster Propagation. Click here for more information.