Temperature preference differences between strains of Mus musculus, associated variables, and ecological implications.

Temperature preference differences were found between three inbred strains of mice, Balb/c having a lower preference than C3H and C57Bl. Hybrids with Balb/c had preferences between the inbred strains, while the C3HxC57Bl hybrid was close to the component inbred strains. Mice choosing low temperatures were heavier, had higher body temperatures and lower hair densities than those choosing high temperatures. Arguments are presented for regarding these associations as adaptive, and being morphological and physiological correlates of the behavioural measure temperature preference, a trait itself of ecological significance in habitat selection. It is considered that these traits are subjected to stabilizing selection for the optimum for a given population, to provide the most efficient habitat selection for that population.Tail length is not so intimately associated with temperature preference and shows overdominance in the direction of long tails unlike the other traits measured. In any case, published data show that while there is a general tendency for shorter tails to occur in environments with low temperatures and vice versa, this is not always true, so that tail length is not necessarily a good guide to the habitat selected.Mice were measured at two ages (15 to 18 days, and 55 to 58 days) for temperature preference, body weight and tail length. Developmental changes were found in that the preferred temperature was lower in the older mice. Furthermore, relative changes between age groups for all traits differed between some genotypes, indicating varying developmental changes according to genotype.