Several different types of bats have been seen at El Pilar. Among them are White-lined Sac-winged bats, Davy's Naked-backed bats, Parnell's Mustached Bats, Short-tailed Fruit bats, and Little Brown bats.

Short-tailed Fruit Bat
The bats are usually dark brown, gray or black and range in size from 2 to 4 inches body length. Many of them are identifiable by the variations in their ear and nose shapes.
Bats generally eat insects, but some such as the Short-tailed Fruit bats eat fruit and the nectar of flowers. They usually start foraging at dusk and through the night returning to their roosts near dawn.
These bats tend to live in middle to lowland forests, gardens and pastures, especially near areas with water where they are likely to find insects. They roost in caves, hollow trees, rock crevices and in buildings.