These bats are about 600 grams to 1600 grams in weight, 23 centimetres in body length and a wing span of 1.2 to 1.5 metres. These bats roost in trees and fan themselves using their wings for thermoregulation. They mate freely, with no pair bonds occurring between males and females. Females are defended by males that live in their roosting tree from intruding males. Baby bats are born between April to early June. They are looked after only by their mother and carried along for around 10 weeks. Become sexually mature at one year.

Often, a colony of Pterpous giganteus consists of thousands of individuals distributed in many roosting trees. The colony in the Royal Botanic Gardens, Peradeniya consists of around 24,000 flying foxes. The colony size size varies due to food availability in its night foraging habitat. These colonies usually roost near a body of water. They feed on fruits, flowers and nectar. They leave the tree at sunset to feed and return after feeding, digesting and resting for several hours. They travel up to fifteen kilometres to and from their roost for night foraging. Depends on sight instead of echolocating.

We spent an hour watching their sleeping, dozing between scratching, occasional changes of branch or tree. And noisy.......