I’ve been seeing a lot of messages with people talking about their tegus preparing for hibernation, or people looking at inducing it. There are a few things that I think tegu keepers should be aware of in order to hibernate their animals with the least chance of complications. What tegus will do in the wild is a lot different than what they will do in captivity, and a lot of these differences, when not taken into account, can lead to lethal consequences in improperly prepared animals. Furthermore, different species do different things during the winter season. The following information really only applies to Tupinambis rufescens , Tupinambis merianae and Tupinambis duseni.

First warning, food. I’ve heard of many that just stop feeding their animal and immediately chilling them for hibernation. Or, on the other hand, captive tegus will usually continue eating until dropping temperatures are too cold to allow proper functioning. This is highly dangerous, and likely will lead to the death of the animal (unfortunately, I know this from empirical evidence, not theory). Digestive enzymes do not work properly at lower temperatures, and food retained in the gut will spoil and rot before it is properly digested, leading to the death of the animal. In the wild, tegus undergo spontaneous aphagia (they stop eating) approximately two months before fully entering hibernation. They don’t stop all at once, but cut down on the amount of food and frequency of eating for the first month, and basically stop eating all together for the second month. During this time, the average daily body temperature (which is roughly equal to their burrow temperature, not their active body temperature) drops from around 30° C to about 17°C (at a decreasing rate of 1°C for every 3 days for the first month, 1°C for every 2 days of the second month) while photoperiod decreases roughly at a rate of 1 minute every 2 days.

The deepest period of hibernation roughly lasts only about 1 month, with an average burrow temperature of 17°C. The arousal period is not sudden, but faster than the entrance period. Temperature increases at roughly 1°C per day, but photoperiod increasing at the same rate it decreased, at roughly 1 minute per 2 days.

Second warning, burrow humidity. It appears the main reason wild tegus hibernate isn’t so much temperature, but water availability. Winter is the driest season of the year in South America, and without water, besides dehydration, there’s no food available either. The burrows that they retreat to are generally much more humid than ambient. Your dormant tegus will lose a lot of water simply through breathing, so it is a good idea to keep the relative humidity of their burrow quite high.

During the hibernation period, a lot of keepers offer food. I highly do NOT recommend this, as stated above, if temperatures are not high enough, this can lead to serious complications. However, at the same time, most keepers are likely unable to get the animals’ burrow temperatures down that low, and therefore what their animals are doing is likely not fully hibernating. If you see a lot of activity from your animals during the period of hibernation (ie. Going in and out of the burrows daily), it is probably safe to feed them a little. If activity is only sporadic (once every few days or so), it is best not to feed them. Always, however, have fresh water available.

Tupinambis teguixin , Tupinambis quadrilineatus, Tupinambis palustris and Tupinambis longilineus are not true hibernators and therefore do not need as much manipulated husbandry, or radical changes. A slight reduction in temperature (maybe roughly down to 25°C), lowering of humidity, and decrease in food frequency and quantity should be all that is needed to simulate their winter period.