Eptesicus – House bats

Members of this genus are known for their adaptability, calm nature, and graceful flight. They belong to the family Vespertilionidae, the largest and most diverse bat family in the world. Despite their wide range, they share a few defining traits: medium-sized bodies, broad wings suited for strong, steady flight, and a preference for roosting in buildings, caves, or tree hollows—hence the name “house bats.”

The best-known member of the genus is the common serotine bat (Eptesicus serotinus), native to Europe and parts of Asia, but other notable species include the big brown bat (Eptesicus fuscus) of North America and the Little serotine bat (Eptesicus diminutus) of South America. Physically, Eptesicus bats tend to have broad, rounded wings, making them excellent flyers in open spaces. Their fur is soft and typically brown or reddish-brown on top and lighter on the underside, giving them a warm, earthy coloration that helps them blend into tree bark and stone walls. Their faces are short and somewhat pug-nosed, with large, expressive eyes and small, triangular ears that enhance their charm and sensitivity to sound.

Behaviorally, Eptesicus bats are nocturnal insectivores, feeding primarily on moths, beetles, mosquitoes, and other flying insects. They use echolocation to hunt, emitting high-frequency calls that bounce off objects and prey, allowing them to navigate and feed in total darkness. Their flight is smooth and controlled, and they often hunt near water bodies, fields, or even streetlights—taking advantage of the insects attracted to artificial lights.

What makes Eptesicus bats especially interesting is their close relationship with humans. Many species have adapted to roost in attics, barns, and old buildings, thriving even in urban or suburban environments. They are also incredibly beneficial to ecosystems, consuming vast numbers of insects every night—sometimes up to half their body weight in bugs! This makes them natural pest controllers and valuable allies to agriculture.