The Biology Of AFrican Fruit Bats
Bats having been mentioned severally as one of the animals responsible for zoonotic diseases such as Ebola virus, SARS, and even coronavirus (COVID) among human population, It is wise to know the biology behind these organisms.
Bats of the family Pteropodidae, also known as megabats or Old World fruit bats, are widely distributed in tropical areas of Africa, Asia, and Oceania. Of 45 genera in the family, 12 are endemic to the Afro-tropical region and two others have representative species on the African continent. African megabats inhabit wooded habitats and are nearly ubiquitous on the mainland and nearby islands with the exception of desert areas. Some species have been implicated as possible reservoirs of the Ebola Zaire virus. We studied the phylogenetic relationships of mainland African megabats using both mitochondrial and nuclear loci in separate and combined analyses. The phylogenetic trees obtained showed four main African clades: Eidolon, Scotonycterini (including two genera), African Rousettus (three species), and the previously identified ‘endemic African clade’ (nine genera). The latter three lineages form a clade that also includes the Asian species of Rousettusand the Asian genus Eonycteris; Eidolon does not show close relationships to other African genera, instead nesting elsewhere in the megabat tree. Although our results confirm many of the conclusions of previous studies, they challenge the taxonomic status and placement ofEpomops dobsonii and Micropteropus, and provide evidence indicating that a new classification at subfamilial and tribal levels is highly desirable. The principal clades we detected represent four independent colonizations of Africa from most probably Asian ancestors. Estimates of divergence dates suggest that these events occurred in different periods and that although local diversification appears to have started in the late Miocene, the more extensive diversification that produced the modern fauna occurred much later, in the Pleistocene.
Studies have shown that bats are the most numerous mammals on earth after rodents. Bats in Africa fall into two major categories: large fruit bats and smaller, insect-eating bats, neither of which attacks people. In addition to a difference in size between the two types, there is a great variation in the extent and details of the wings, which are formed by the naked membrane of skin that extends from the neck to the wrist and between the fingers, and finally to the tail. Wing shapes vary from species to species. Usually, the swift fliers have long, narrow wings while the slow fliers have broad, rounded ones.
The bones of the hand that support the wing membrane are unusually long. The hind legs are rotated 180 degrees at the hip joint, so the knee flexes backward rather than forward. This arrangement does not hamper the bat when it is perched but rather helps it push off from the roost for a quick getaway. They are very agile even on land, scuttling quickly over objects and squeezing their bodies through small openings.
Fruit bats feast largely on fruit. They have large cheek pouches, enabling them to take food to be eaten at another perch, away from disturbances. They are known for their noisy eating habits. To obtain water, bats munch on soft wood and bark. They usually eat overripe and unmarketable fruits, and they may even help reduce fungi and fruit flies in commercial plantations. Insect-eating bats are natural pesticides, eating mosquitos and other varieties of insects.
They also play an important role in the environment. Many plants are dependant on bats for both pollination and seed dispersal. Every November, more than eight million bats migrate from Zambia forming the largest mammal migration in the world. Migration occurs when food sources become low.
With few exceptions, they are nocturnal and emerge from their daytime roosts only when the light of day is fading. During the day, fruit bats often roost hanging upside down in the exposed branches of trees. Other species also roost upside down in large colonies that may number in the millions, in dark caves. They also live in smaller colonies in crevices, hollow trees, and around houses.
Fruit bats have an acute sense of smell and large eyes that give them good night vision, both of which help them locate fruit and nectar. Insect-eating bats find their way in total darkness by emitting high-pitched squeaks through the nose or mouth as they fly. These sounds bounce off of objects and echo back to their ears. This method of echolocation, or bat sonar, allows them to locate, capture, and eat insects in midair while still detecting and avoiding objects as fine as a human hair. However, to send and receive these location signals, they have developed unique ears and noses.
Level of Parental Care
Bats like every other mammals care for their young, and usually, one bat is born a year to an adult female. The mother nurses the young for up to four months. In some species, the mother carries around the infant for five or six weeks, but in others, the mothers leave them in “nurseries” while they go out to feed. Even though a young bat is two-thirds grown at six weeks, it will not become sexually mature until two years of age.