Age determination, age structure, and longevity in the mole Scalopus aquaticus (Mammalia: Insectivora)

Authors

  • Gregory D. Hartman

    1. Department of Biology & Museum of southwestern Biology, university of New Mexico, Albuquerque, NM 87131, USA, and 1Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, USA
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    • *Department of Biological & Environmental Sciences, McNeese State University, Lake Charles, LA 70609, USA


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Abstract

Three hundred and eighty-two moles, Scalopus aquaticus, were collected from 16 sampling grids located within a 23 km2 area in South Carolina, USA. Age of moles was determined using tooth wear. Both the mean and median ages of trapped moles were c. two years; the oldest mole was in its seventh year of life. More than 50% of the individuals are estimated to die during the first six months of life; adult survivorship was relatively high and age-dependent. There was differential mortality between the sexes, and females lived longer than males. Scalopus aquaticus in South Carolina lived c. 1.2 times longer than the maximum lifespan predicted on the basis of body mass. Pooled samples of moles yielded the expected age distribution, with fewer individuals occurring in successively older age classes. However, based on bootstrap estimates of the variance in age structure, samples from some grids contained significantly more young or old individuals than expected due to sampling error. Mole populations appear not to be in demographic equilibrium at this local scale, but instead conform more closely to a metapopulation-type of structure.

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