Box Turtle Hibernation

A Colorado State University graduate of 1979, Roger Klingenberg is a widely recognized researcher, author, lecturer and instructor of reptile medicine and surgery. He is well known among herpetologists for publications including Understanding Reptile Parasites and The Ball Python Manual. He is a managing partner in a three-person small and exotic animal hospital and is active in the Association of Reptilian and Amphibian Veterinarians.

Hibernating Box Turtles
Below is the text for Dr. Klingenberg’s article on hibernation. View article with monitor screen at maximum size. If your computer can read PDF files, this article is also available in that format. Please view it here: Hibernation article

No in-depth studies have determined exactly why hibernation is necessary to the long-term physiological well being of mature North American box turtles (Terrapene sp.). But those that are not allowed to hibernate usually experience a progressive physical and mental decline. Ovulation and spermatogenesis, and therefore successful reproduction, will not occur without proper seasonal cooling. It follows that hormones other than reproductive may also be affected by hibernation. One hypothesis is that hibernation prevents damage to the thyroid gland. This author hypothesizes that the lack of proper hibernation may lead to irreparable damage to the immune system. Seasonal changes have been seen in the status of the immune system. Populations of white blood cells change from summer to fall, with decreases in lymphocyte counts and overall splenic pulp immune population. Without replenishing these defense systems through hibernation, the turtles become immunocompromised.

Pre-Hibernation Evaluation

When mature box turtles are ready to hibernate, they stop eating, become lethargic and attempt to burrow or hide. This point in time varies with the locale and local population of turtles. In general, this begins in mid-September to mid-October but could commence later in the fall and winter. It is essential that box turtles are healthy prior to hibernation. A pre-hibernation examination, including an accurate body weight, should be the first step toward the winter nap. The turtle is weighed on a gram scale so its weight can be monitored every 2-3 weeks during the course of hibernation.

Clinical Signs of a Box Turtle Too Debilitated to Hibernate
Low body weight
Weakness, lethargy
Ocular lesions
Nasal discharge
Open-mouthed breathing
Physical and mental “burn out”