The northern long-eared Myotis has light brown fur on its back with paler gray fur on its underside. The face, ears, and membranes are dark. This species' ears are long compared to other bats in the Myotis genus and feature a characteristically sharp and pointed tragus. In the summer, the northern long-eared Myotis can be found in its more northern range, preferring dense forest stands. Roosts are primarily located in trees and buildings, with maternity roosts often found beneath the exfoliating bark of dead trees or within tree cavities. Winter roosts are typically located in small caves or crevices, such as underground mines. Typically, this species roosts alone or in small groups (about 20-60 females to a maternity roost). Moths constitute the primary diet of this species. The fungal pathogen white-nose syndrome, has caused population declines of up to 99% at hibernation sites.