Mauritian Tomb Bat, Taphozous mauritianus
The Mauritian tomb bat (Taphozous mauritianus) is one of 51 species of sac-winged bats. It is native to Madagascar and central and southern Africa. The range of the Mauritian tomb bat is large, encompassing many areas of Africa and the surrounding islands. It can be found in arid habitats as well as in grassland, tropical, and semi-arid habitats. It prefers habitats within moist savannah habitats, however, with plenty of room to fly and roost. Because of its dry habitat choices, these bats are able to conserve water by having an enlarged medulla, the section of the kidney that gathers waste.
The Mauritian tomb bat has been seen around rivers and swamps, most likely because of the abundant food resources found there. In Sao Tomé and Principe, colonies have been spotted within cocoa trees of plantations. These trees provide exceptional habitats, offering great food sources and abundant space to fly. It prefers to roost in caves, trunks of hollow trees, and crevices. These areas offer spacious roosts with plenty of space for the bats to take off. Since the appearance of humans in this bat’s range, it has adapted to living in different roosts, such as buildings and the outer walls of tombs.
In 1818, French naturalist Étienne Geoffroy Saint-Hilaire discovered the Mauritian tomb bat. He compared it to the recently discovered Egyptian tomb bat, which was similar in size but not in coloration. The genus name of this bat, Taphozous, is derived from the Greek word for grave or tomb. The second part of its name, Mauritianus, means “of Mauritius”, referring to the location in which it was found. Although the name suggests that it resides in dark, close tombs, the Mauritian tomb bat does not dwell in these areas, but can be seen roosting outside of them.
The Mauritian tomb bat can reach an average length of up to 4.3 inches and can weigh up to 1.2 ounces. Its dorsal fur appears to be many colors, including grey, white, and black. The underbelly is completely white, a unique trait among bat species. The wing membranes hold no fur, and are brown to beige in color. These wings will contract when the bat is not in flight, and stick close to the body, allowing it to crawl uninhibited. Young Mauritian tomb bats are lighter in color, appearing to be lighter grey.
There is little indication of sexual dimorphism between male and female Mauritian tomb bats. During breeding season, the male’s genitals protrude and are darker in color, but when breeding season is over, the genitals retract into an abdominal cavity. Males also display a gular sac on the base of the jaw, which releases scents for mating and marking territory. In some areas, like Mozambique and Nigeria, females do not display this scent gland, while in West Africa the gland is present but less pronounced.
The Mauritian tomb bat prefers to roost in small groups of up to five individuals, and these groups usually consist of only one sex. When grouping together, males and females will remain at least 3.9 inches away from each other. Females tend to roost in groups between 3 to 30 individuals, but they are not seen clumped together like most bats. Instead, they prefer to roost with plenty of space between them, with the exception of a mother and her young. At the Shai Hills Resource Reserve in Ghana, one colony number at least 100 individuals was found. Typically, the bats will roost with their bellies up against a surface.
Like most bats, the Mauritian tomb bat is nocturnal, and it can be seen hunting and moving about during the nighttime. During the day, it will rest at a roosting site, but it does not always sleep. It is a very attentive bat, and if disturbed, it will not hesitate to fly off to a secondary roosting site to rest. However, they rarely fly large distances from the initial day roosting site, and eventually, these frequented roosts become stained by secretions from the gular sack that appear to be brown and triangular on the surfaces.
The Mauritian tomb bat will mate in different seasons depending on its location. In Southern Africa areas of its range, it may mate twice a year producing one or two pups in February to March and October to December. In different areas, some tomb bats will give birth in April or May, after a pregnancy of up to five months. Mothers take complete responsibility of young, and will allow the pup to cling to the belly while roosting and in flight. The pup will nurse until it is ready to fly and eat a solid insect diet, and it may remain with its birth colony after it is weaned.
As is typical with bat species, the Mauritian tomb bat uses echolocation to communicate, hunt, and maneuver through the air. It will also use chirps, squeaks, and other noises to communicate, as well as scent markings. These bats have a unique type of echolocation call that consists of two or three chirps with long pauses of silence between them. Using different frequency modifications allows these bats to hunt in many habitats, giving them an edge over other bat species.
Despite having advanced echolocation, the Mauritian tomb bat prefers to use sight during the day to keep watch and occasionally forage for food. Unlike most bats, the eyesight of this tomb bat is considered unique, and has been compared to that of Old World bats. Both have been found to contain the dim-light gene, or RH1, that allows for activity in brighter habitats.
The main diet if the Mauritian tomb bat consists of moths, although during the day it will consume termites and butterflies. It provides a service to humans by keeping the insect population low, which helps to decrease the number of cases of malaria caused by insect bites. They prefer to hunt for food over open areas of water or fields, where they can easily swoop down and consume the food midflight.
Because of its huge range, the Mauritian tomb bat is thought to be large in number, although it is not often seen. The IUCN has given it a conservation status of “Least Concern” and it does not require any conservation efforts due to this.
Image Caption: A pair of Mauritian Tomb Bats (Taphozous mauritianus), in Ankarafantsika, Madagascar. Credit: Frank Vassen/Wikipedia(CC BY 2.0)