M ost bats have a single young each year after a gestation period of about two months. Young develop quickly and learn to fly at about 1 month of age. Senseless human harassment kills many of them, and some die because of the stress of hibernation. Maximum longevity in bats is remarkably long for a small mammal. The little brown bat can live over 30 years.
Bats sleep all day and some of the night, and some hibernate for eight or nine months of the year.
Adult bats are such swift, efficient hunters they can fill their stomachs in an hour. The little brown myotis is estimated to eat one-third its body weight in insects within half an hour. One bat expert figures Brazilian free-tailed bats being studied in Texas could consume nearly 20,000 tons of insects in a year statewide. Some adult bats can devour 12 mosquito-sized insects per minute. The pallid bat feeds primarily on the ground.