Big Brown Bat

Actual Size:  Body length of 4-5”, with wingspan of 12-13”

Characteristics:  Copper-colored fur with lighter belly fur. Small round ears that are black in color. Broad nose and black wings.

Habitat: Inhabit a wide range of area, from deserts to cities and suburban areas.


  • Distributed widely nation-wide
  • Found in all habitats from meadows and deserts to cities and mountains
  • Insectivorous and prefer to eat beetles rather than other insects

Big Brown Bats in Puerto Rico

The big brown bat is one of the bigger bat species and also likely the most widely dispersed throughout the continent. They are known to withstand conditions that other types of bats can’t, which is why they’re commonly found in cities and suburban areas alongside wooded areas. These bats prefer beetles but will also eat moths, flies, wasps, and flying ants. Colonies range from 20 to 300 individuals and big brown bats can live a long time in the wild. That said, most die off during their first winter due to malnutrition throughout hibernation.

Big Brown Bat Habitat

Big brown bats have been found in a variety of habits including meadows, deserts, mountains, forests, suburban areas, and cities. They will hibernate in caves, mines, walls, attics, or other buildings. They enter into hibernation in November, often less than 50 miles away from their summer roosts. They hibernate in small groups and come out in the springtime. In Puerto Rico, they are most often seen at night, but can become a nuisance when they nest in properties over the winter.

Big Brown Bat Behaviors, Threats or Dangers

The big brown bat is nocturnal and will roost in several places during the day. They eat a number of insects but prefer beetles and are significant predators of agricultural pests. The average life expectancy is a bit over 6 years. The main threat of big brown bats is the fact that they roost and hibernate in buildings. Especially in the winter, they will enter homes and buildings for warmth in your attic or walls. Big brown bats are carriers of disease and it’s important to exercise extreme caution if you come across one. Contact your local wildlife control experts for help with big brown bats.