Effect of temperature on body temperature and resting metabolic rate in pups of Eothenomys miletu

Abstract

In order to investigate the ability of ambient temperature and thermoregulation in Eothenomys miletus, body temperature and resting metabolic rate (RMR) were measured during postnatal development (1-49 day) when E. miletus exposed different ambient temperature. The result showed that: body temperature and RMR of pups in E. miletus increased according to the increase of ambient temperature during 1 day to 7 day, showed character of poikilotherms; body temperature of pups were lower in low temperature (5 oC, 10 oC), relatively and RMR increased significantly when day age is 14 day, it indicated that the pups showed a certain degree of thermoregulation in this phase. Its thermoregulation ability developed quickly during 7 day to 14 day. RMR of pups was extreme significantly higher in low temperature than that in other temperature when day age was 21 day, it showed that the pups had some thermoregulation to low temperature stimulation. The RMR of pups was showed increasing trend in high temperature (35 oC) when 28 day; on 35 day and 42 day, the thermal neutral zone were 22.5 to 30 oC and approaching its adult level. All of these results indicated that pups of E. miletus in the different growing period had different thermogenesis and energy allocation to maintain stable to body temperature, thermogenesis was weaker in the early phase of postnatal development, most of energy is used to its growth. After pups were weaned, the ability of constant temperature and thermoregulation developed quickly to adjust variations of environment during postnatal development.