Tools of Hibernation Measurement and Interpretation (TOHMIN) for quantifying various values from body temperature fluctuation during hibernation

Abstract

Hibernation is a fascinating physiological phenomenon that dramatically reduces basal metabolism and thermogenesis, resulting in a large deviation in body temperature (Tb) from homeothermic ranges in mammals. Although high-resolution long-term Tb recording in wild or laboratory animals has become possible through data loggers, few standardized methods to analyze details of hibernation patterns are available, making it difficult to reproduce and compare the results across different studies and species. To facilitate the analysis of hibernation patterns and accelerate hibernation research, we developed an open-source program, tools of hibernation measurement and interpretation (TOHMIN). As a proof of concept, we analyzed a dataset from two pilot studies on (1) the effects of distinct diets on hibernation patterns and (2) differences in hibernation patterns between males and females in a mammalian hibernator, Syrian hamster (Mesocricetus auratus), and found previously undetectable fine-scale differences in hibernation patterns. First, different types of diets affected the duration of periodic arousal. Second, females maintained higher body temperatures during periodic arousal than males. Third, the duration of the pre-hibernation period was negatively correlated with the hibernation period for this species. Thus, TOHMIN accelerates studies to assess the effects of various experimental manipulations on hibernation phenotypes in mammals.