Osteological and ocular anomalies in juvenile big brown bats (Eptesicus fuscus)

Osteological and ocular anomalies are reported from four wild-taken, juvenile (16–32 days old) big brown bats (Eptesicus fuscus) from eastern Massachusetts. Anomalies include polydactyly, deformed sacral and caudal vertebrae, underdeveloped radius and ulna, closed eyelids, unpigmented choroid layer, undifferentiated retina, and an underdeveloped lens. Bats with osteological anomalies showed no apparent ocular deformities and those with ocular deformities showed no evidence of bone anomalies. The combined incidence of anomalies represents 3.3% of the young bats born in this maternity colony in 1978.