Abstract To survive hibernation, the fat-storing hibernator accumulate substantial energy reserves in the form of body fat. However, the mechanism by which these naturally fattening animals avoid persistent obesity remains unclear. In this study, we investigated changes in gut microbiota of Daurian ground squirrels (Spermophilus dauricus) during the fattening period and examined their impact on host metabolism. Our results showed that after fattening, body fat significantly increased, the metabolic substrate shifted from carbohydrates to lipids, and the composition and structure of the gut microbiota were changed. The subsequent weight loss observed may be attributed to an increase in specific bacterial species, such as Phascolarctobacterium faecium, Bacteroides uniformis, Bacteroides intestinalis, and Butyricimonas virosa, which are known to be associated with reduced body weight. Consequently, from the perspective of the gut microbiota, this study suggests that changes in specific bacterial taxa may be associated with post-fattening weight loss and seasonal body weight fluctuations in ground squirrels.
Liu et al. (2026) studied this question.