Is weight a reliable index to age in microtine rodents?

Abstract

F uller W. A., 1988: Is w eight a reliab le index to age in m icrotine rodents? A cta theriol., 33, 17 : 247—261 [W ith 9 Tables & 4 Figs.] Frequency d istrib u tio n s of " age " classes based on body w eights and on m olar developm ent and m orphology are com pared both w ith in and am ong years in sam ples of Clethrionomys gapperi. W eight class lim its th a t give the best fit to m olar class frequencies v ary from y ear to year. Body w eight is a poor pred icto r of the m olar class of an individual. W eight class lim its d eterm ined from all age classes in a sam ple gave poor results w hen applied to the sexually m a tu re com ponent only. In in tery ear com parisons, body w eight and m olar m orphology gave con­ flicting view s of differences in age stru ctu re, and hence of the dynam ics of the population. Body w eight should be used w ith caution as an index to age of Clethrionomys, an d by extension, to o th er m icrotine rodents. [D epartm ent of Zoology, U niversity of A lberta, Edm onton, A lb erta T6G 2E9, C anada 1