Flexi Says: Flying foxes and fruit bats are the common names for the genus Pteropus. These are the largest bats in the world with wingspans up to 1.5 m (4 ft 11 in) and weights up to 1.6 kg (3.5 lb). Flying foxes are prolific disease reservoirs. This means they carry dangerous diseases without showing any symptoms and then pass them on to humans or other animals. Examples are Hendra and Marburg viruses. Due to their large size and expansive ranges, flying foxes have several adaptations, like large wings, to help them fly. One particularly interesting adaptation is that they digest food in as little as 20 minutes so they can quickly excrete waste to stay as light as possible. Flying foxes have appendages customized to let them spend a lot of time in trees.