MICE, VOLES AND HAMSTERS - METABOLIC RATES AND ADAPTIVE STRATEGIES INMUROID RODENTS

The hypothesis that the metabolic rates of mammals are convergent and depend on functional adaptations was tested against the claim that tax onomic affiliations sufficiently account for variations in metabolism. Basal metabolic rates (BMR) of 90 species of muroid rodents (Rodentia , Muroidea) were collected from literature and compared with data on t heir life history traits: food habits, climate, habitat and biotope. U sing clustering procedures and factor analysis three typical strategie s were delimited: ''mouse'', ''hamster'' and ''vole''. The last one is related to low-quality food; the other two include selective omnivore s, with ''mice'' preferring rich and moist habitats and ''hamsters'' d welling in arid steppes and deserts. These groups are only partly cong ruent with the Muridae, Cricetidae and Arvicolidae families. All group s demonstrate similar dependence of BMR on body weight, but ''voles'' and ''mice'' have a significantly higher BMR than ''hamsters''. In con trast, Cricetidae and Muridae have significantly lower BMR than Arvico lidae (ANCOVA). Analysis of residuals within ANCOVA for groups and for families corroborates this. Both factors, taxonomic affiliation and f unctional adaptations, independently exert similar effects upon the va lue of BMR in muroid rodents.