The gray Myotis has light to dark brown fur with long, dark ears. Ears are longer than many other Myotis species, extending 1/4 cm (7 mm) beyond the nose when laid forward and featuring a long and thin tragus. The gray Myotis has a keeled calcar. When foraging, gray Myotis prefer to feast on flying insects like mayflies and beetles. This species almost exclusively roosts in caves throughout the year. In the summer, they can be found in warmer caves located in close proximity to water sources. In winter, the species prefers cool, deep, well aerated caves. Appropriate cave temperatures are essential for hibernation and rearing young. During winter, it is estimated that 95% of the known population of gray Myotis occur in just nine caves.