Townsend’s big-eared bats (Corynorhinus townsendii) interrupt their reproductive cycle by storing sperm
and delaying fertilization, thereby minimizing energetic demands of hibernation and reproduction. During our long-term
study (2013–2024) of female Townsend’s big-eared bats in eastern California, we observed 21 pinkies (i.e., bat pups
≤7 days old) and used known reproductive parameters, including a 56- to 100-day gestation period, to estimate long-term
sperm storage potential for Townsend’s big-eared bats. Our 218-day long-term sperm storage estimate is longer than the
previously reported estimate of 108 days. Our results indicated greater reproductive plasticity than previously estimated,
which may enhance this species’ ability to adapt to long- and short-term environmental stochasticity.

Citation: Randel, C.J. III, A.M. Long, J.M. Kunberger, and M.L. Morrison. 2025. Extended sperm storage duration in female Townsend’s big-eared bat (Corynorhinus townsendii). Western North American Naturalist 85: 683-685.
Available at: https://scholarsarchive.byu.edu/wnan/vol85/iss4/10