title: Huddling, locomotor, and nest-building behaviors of furred and furless Siberian hamsters.
abstract: Rodents living in the cold employ both behavioral and physiological mechanisms to achieve thermoregulation. We examined the impact of fur loss on behavioral thermoregulation in cold-challenged Siberian hamsters (Phodopus sungorus). Intact female hamsters exposed to an ambient temperature (T(a)) of 5 degrees C increased their general locomotor activity by 50% relative to animals maintained at 23 degrees C. At both T(a)'s, fur removal resulted in substantial increases in daily food intake (37% and 22% at 5 and 23 degrees C, respectively) but did not affect the amount of locomotor activity; increased food intake after fur loss evidently is not caused by increases in locomotor activity. Furred hamsters housed in groups of three at 5 degrees C consumed 16% less food per day than did singly housed individuals. Fur removal resulted in identical 39% increases in food intake in group- or singly housed animals. Energy savings that accrued from huddling were identical in furred and furless animals; this behavior conserves energy even in the absence of an insulative pelage. The availability of nesting material resulted in an 18% reduction in food consumption in intact animals kept at 5 degrees C. The increase in food intake produced by fur removal was attenuated by approximately 80% when furless animals had access to nesting material. Huddling and nest-building behaviors each ameliorate energetic challenges posed by absence of fur; animals that concurrently employ several modes of thermoregulation realize substantial energy savings in the cold.
authors.affiliation: Department of Integrative Biology, University of California at Berkeley, Berkeley, CA 94720, USA. ask5j@virginia.edu
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Kauffman
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Paul
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Butler
authors.forename: Irving
authors.initials: I
authors.lastname: Zucker
mesh_terms: D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D001835:Body Weight; D003080:Cold Temperature; D006224:Cricetinae; D004435:Eating / Q000502:physiology; D004734:Energy Metabolism; D005260:Female; D006197:Hair / Q000502:physiology*; D006799:Housing, Animal; D009043:Motor Activity / Q000502:physiology*; D009425:Nesting Behavior / Q000502:physiology*; D017111:Phodopus / Q000033:anatomy & histology / Q000502:physiology* / Q000523:psychology*; D012934:Social Isolation