Big Brown Bat


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

Characteristics: Copper-colored fur with lighter belly fur. Small, black round ears. Broad nose and proportionally large ears. Black wings.

Habitat: Found in many habitats found around the Modesto CA area including deserts, meadows, cities, to forests and mountains. Will hibernate in caves and buildings.


  • Distributed widely across Modesto CA.
  • Insectivorous and prefers to eat beetles over insects.
  • Found in all habitats from meadows and deserts to cities and mountains.

Big Brown Bats in Modesto CA

True to its name, the big brown bat is one of the biggest bat species. It’s also fairly common around the Modesto CA area. Known for their resiliency compared to other bats, big brown bats can routinely be found in cities and suburban environments near wooded areas. Their favorite food is beetles and they use their powerful jaws to chew through hard exoskeletons. When beetles aren’t available, they also eat moths, flies, wasps, and flying ants. Big brown bats live an average of six years in the wild and their colonies range from 20 to 300 individuals. That said, many die off during their first winter due to malnutrition during hibernation.

Big Brown Bat Habitat

Big brown bats have been found in a variety of Modesto CA-area habitats including meadows, deserts, mountains, forests, suburban neighborhoods, and even urban environments. They hibernate in caves, mines, walls, attics, and buildings. They enter into hibernation in November, often less than 50 miles away from where they roost in the summer. They hibernate in small groups and reemerge in the springtime.

Big Brown Bat Behaviors, Threats, or Dangers

The big brown bat is nocturnal and roosts during the day. They eat a variety of insects but favor beetles and agricultural pests. The main threat to big brown bats is humans, especially if they roost or hibernate in buildings. They will enter homes and buildings for warmth. Big brown bats are carriers of diseases including rabies and it’s important to exercise extreme caution if you come across one. If you notice a bat has made its way into your building, never approach it or attempt to handle it yourself. Always contact a professional wildlife control company.