Torpor expression and patterns in 3 sympatric rodents from Inner Mongolia

Area of Science:

• Physiology
• Ecology
• Animal Behavior

Background:

• Rodent diversity in Asian deserts is high, yet knowledge of their energy conservation strategies like torpor and hibernation is limited.
• Small mammals globally use these strategies to survive harsh conditions, but specific patterns in Asian desert rodents remain understudied.

Purpose of the Study:

• To quantify long-term torpor and hibernation patterns in sympatric desert rodents under controlled conditions.
• To investigate the influence of environmental cues such as photoperiod and temperature on these physiological responses.

Main Methods:

• Utilized temperature transponders and data loggers to monitor torpor expression in desert hamsters (Phodopus roborovskii, Cricetulus barabensis) and jerboas (Dipus sagitta).
• Animals were acclimated to short photoperiods and low ambient temperatures (T_as) for six months in captivity.
• Observed spontaneous and food-deprivation-induced torpor and hibernation patterns.

Main Results:

• Both hamster species exhibited spontaneous daily torpor, with striped hamsters showing deeper and longer torpor bouts than desert hamsters.
• Only one jerboa entered spontaneous hibernation; however, all jerboas hibernated when food-deprived.
• Hamsters maintained body mass, while jerboas significantly increased body mass, likely in preparation for hibernation.

Conclusions:

• Short photoperiod and moderate low temperatures induce spontaneous daily torpor in desert and striped hamsters, suggesting regular wild use.
• Hibernation in jerboas is triggered by food scarcity at low temperatures, highlighting its role in surviving resource-limited periods.