Bulldog or Fisherman Bat- Noctilio leporinus

STATUS: Fishing bats are found in lowland and coastal habitats over a large area of Central and South America, and throughout the Caribbean. Often locally abundant, they are restricted by the availability of large fresh-water sources (reservoirs, lakes, ponds, rivers).

IDENTIFICATION: The rancid fishy smell, russet-orange color, white stripe of fur down the center of the back, and the extremely large feet (20mm long = longer than the bats' head) readily distinguish this large bat from anything else in the region. The large square head give this bat one of it's alternate names - the Bulldog bat. The long thin pointed ears are also distinctive, but may be curled back against the head if the bats are undisturbed. The large wingspan and the relatively stiff-looking, slow flight close over the surface of calm water (like ponds or lagoons) are typical of Fishing bats. Repeated splashes as the feet are dipped into water to catch fish or insects can also sometimes be heard. The tail membrane is very large and is supported by a long spur (calcar) of cartilage growing from each ankle. These spurs are moveable, and allow the tail membrane to be rolled up like a sail between the back legs so that it does not interfere with catching fish. For this reason, the tail membrane may appear much smaller than it actually is. The fur is very short, and ranges from brown-orange to yellow in color.

ROOSTS: Hollow trees, dark sea caves, and crevices in rock-overhangs seem to be the common sites used as roosts by these bats. Fishing bats and their roosts have a characteristic fishy odor which is unmistakable - this smell is not due to the presence of fish remains at the roost, rather it is a oily secretion produced by these unique animals.

DIET: As their name implies, these bats catch and eat small fish but will also eat large insects that they snag on the surfaces of ponds or can hawk from the air (mainly beetles/crickets). During hard times, insects and small crabs may be their only food source. These bats fish like ospreys, trawling their enlarged feet through the water, gaffing fish out of the water with their claws. They fish in either fresh or salt water, but need fairly calm conditions (flat surfaces) because they use their echolocation to detect ripples made by fish feeding just beneath the surface of the water. Their large drooping cheeks are actually large storage pouches which allow the bat to stuff minnows or partly chewed food into its cheeks and yet continue to hunt. Fishing bats catch fish like ospreys, raking their feet through the water as they fly along - you may be able to see this behavior and hear the tiny splashes as their feet hit the water. Their droppings are large (15-20mm long, 3-4mm in diameter) and irregularly shaped. The droppings often look silvery because of the tiny fish scales they contain; if the bats have been eating shrimps or small crabs, the droppings may be pink or orange.

REPRODUCTION: Mating probably occurs around December, with a single baby usually being born the next April or May. Possibly there is a second mating season soon after the females have given birth, with this second baby being born around November the same year. Females producing milk have been found at all times of year.

SIZE: Forearm length - 86 mm (range 84-93mm); Mass - 64g (range 60-70g); Wingspan - approx. 600mm; Head+body length - approx. 120-130mm.

COMMENTS: Other names Greater bulldog bat, Fisherman bat. Fishing bats are beneficial in helping to control insect numbers.

REFERENCES: Mammalian Species No. 216: Noctilio leporinus by Craig S. Hood & J. Knox Jones, Jr. 7pp (American Society of Mammalogists, 1984)

See Entry: Walker's Mammals of the World
Online version 5.1, by Ronald Nowak, 1997