Mauritian Tomb Bat - Behavior and Ecology

Behavior and Ecology

The Mauritian tomb bat is often found in groups of around five individuals. These groups are usually either made up of entirely male or female individuals; when they are found in mixed gender groups, the two sexes are separated by at least 100 mm. Females live together in groups of three to thirty, while males live alone except during the mating season. Unlike some species of bats, they do not roost close together in tight packs; instead they are found spaced out loosely, with the exception of a mother and her offspring. There are places where groups of at least a hundred bats have been found, one example being the Shai Hills Resource Reserve in Ghana.

They usually roost with their ventral side flat against a surface. The Mauritian tomb bat is nocturnal and rests during the day; however, it does not sleep much and remains watchful while roosting. If disturbed, they will fly off to another site or move quickly up under the eaves of the building. Very rarely do they travel far from their day roosting site, and roosts are often recolonized. Over time these sites become stained with gular sack secretions and urine. The stains are typically a rectangular brown shape roughly 150 mm long and 100 mm wide.

The semi-diurnal activity of tomb bats has led to the evolution of relatively good eyesight, unlike most echolocating bats. Their vision is very similar to the eyesight found in that of Old-World bats. The presence of the dim-light (RH1) gene in both the tomb bats and Old-World bats suggests convergent evolution of this gene in a similar light-rich environment. The Mauritian tomb bat can detect movement from a distance away, which suggests that the bat's eyesight is superior to that of other insect-eating bats. This advanced eyesight plays a large role in finding a suitable roost for the day and detecting predators. The Mauritian tomb bat is, for the most part, a nocturnal hunter, though it does occasionally forage during the day. They prefer to hunt in open spaces such as over an open field or body of water, so they can easily swoop down and grab the insects they feed on. The Mauritian tomb bat captures its prey and consumes it while in flight.

Their preferred food is moths, though during daylight hours they will prey upon butterflies and termites. In regions where the bats live, they often are a factor in keeping pest populations down. This is important since the bats inhabit areas often plagued by insect-borne diseases such as malaria. They usually wait for complete darkness before foraging. Over open areas, they can detect their prey at long ranges. They periodically make dives when hunting, and with each dive, they increase the rate of echolocation.