Longevity of the Northern Short-Tail Shrew

Abstract

Long-term longitudinal studies can provide information on habitat quality over time. The Short-tailed shrew (Blarina brevicauda) is carnivorous, abundant in most habitats and lives 18 months or less. Ageing criteria based on weight or reproductive condition provide unreliable results since shrews are nearly adult weight at emergence from the nest and can begin reproduction shortly thereafter. The only reliable ageing criterion is microscopic evaluation of wear on cheek teeth of preserved specimens: not applicable to live animals. We used field measurements of incisors of marked individuals trapped repeatedly over a 7 month period to see if incisor length could be reliably related to known age. We live trapped short-tailed shrews (Blarina brevicauda) at SUNY Oswego’s Rice Creek Field Station every 1-2 weeks, May- November 2007. Individuals were marked with PIT tags and released. We trapped 62 individuals a total of 263 times (max. captures/individual = 14; max. interval between first and last capture: 193 days). Tooth wear is measurable over longer intervals of time, and incisor length can be used to place individuals into 3 age classes.