关键词: 额外耗能, 热能代谢, 聚群, 体温调节, 水貂, 黄鼬, 幼仔

Abstract: 1. The paper reports the effect of the 3 or 4 animals of a huddling and ambient temperatures(from 15℃ to 33℃)on heat energy metabolism and thermoregulation of newborns of three species' fur animals,viz.weasels(Mustela sibirica)3-35-day-old, 1-44-day-old minks(Mustela vison)and 1-24-day-old domestic rabbits.2. The heat energy metabolism of the newborns were measured under a simple closedsystem respirameter.3. The body temperatures of the newborns rose or fell with ambient temperatures until they reached homeothermic days old(Figs. 1 to 3 ),but the heat energy metabolism (cal/g/day) increased with the ambient temperatures falling (Figs. 4 to 6 ). The increased extra heat energy was not enough to maintain the steady body temperature level during the falling of ambient temperature.4. The homeothermic ability of newborns of the three species increased with their age(Figs. 1 to 3 ).5. (1) Exposed to coldness the body temperatures of the huddling of newborns were higher than singles(Figs 1 to 3 ):For rabbits of l-18-day-old,the average body temperature of a huddling was higher by 1.09℃,0.5℃ and 0.3℃ under ambient' temperatures of 15℃, 25℃ and 33℃ respectively than singles;Minks (Mustela visora)l-44-day-old, the average body temperatures of a huddling was higher by 2 ℃ and 0.72℃ than singles under 22℃ and 26℃ respectively.Weasels(Mustela sibirica) 3 -35-day-old,the average body temperatures of a huddling was higher by 1.38℃ and 0.97℃ than singles under 22℃ and 25℃ of ambient temperatures respectively. (2) But the heat energy metabolism (cal/g/day)of a huddlirg is lower than the single when exposed to coldness(Figs. 4 to 6 ):Rabbits l-6-day-old,the average heat energy metabolism(cal/g/day) of a huddling was lower by 35.02% and 37.75% than singles urder 25℃ and 33℃ of ambient temperatures respectively.Minks (Mustela vison) 1-40-day-old, the average heat energy metabolism (cal/g/day)of a huddling was lower by 40.68% and 46.95% than singles under 22℃ and 26℃ of ambient temperature respectively.Weasels(Mustela sibirica)3-35-day-old,the heat energy metabolism(cal/g /day)of a huddling was lower by 39.45% and 27.41% than singles under 22℃ and 25℃ of ambient temperature respectively.6. It is an ecological strategy that any uneffective extra energy consumption of the newborns should decrease in their huddling or in a warm nest.

Key words: Extra heat energy, Heat energy metabolism, Huddling, Thermoregulation, Mink, Mustela vison, Weasels, Mustela sibirica, Newborns