Bats are the only mammals capable of sustained flight. Rather than flexing their forelimbs to fly, as birds do, they flap their webbed digits, scooping handfuls of air. Most bats eat insects, but about a third of bats species are frugivores, such as Pteropus giganteus, also known as the giant fruit bat or flying fox. Giant fruit bats weigh 600 to 1600 g and have a wingspan of 1.2 to 1.5 m. They live in tropical forests and swamps throughout Bangladesh, Myanmar, India, Pakistan, and Sri Lanka. During the day they roost by the hundreds in large trees, hanging upside down by their feet and wrapped in their membranous wings. When they are not dozing, they fan themselves to aid in thermoregulation, move around in the tree, and vocalize to communicate with one another. A video recording of the roosting behavior of fruit bats can be found at http://www.indiavideo.org/kerala/land-and-people/flora-and-fauna/wildlife/animals/the-indian-flying-fox-586.php.
Cole TB. Giant Indian Fruit Bat. JAMA. 2009;302(16):1736. doi:10.1001/jama.2009.1503