The benefits of bats
The benefits of bats
Clare Mateke studies bats as part of her work as a Mammalogist at Livingstone Museum.
From October through to December is a good time of year to see bats and especially at Kasanka National Park in Zambia’s Central Province, where the straw-coloured fruit bat roosts in numbers estimated at around 8 million – believed to be the highest density of mammalian biomass on the planet as well as the greatest mammal migration known to man.
When ‘out on the town’ at night in Livingstone, or watching the sunset over the Zambezi, one often notices the smaller members of the wildlife community – the insects and the bats. There are nearly 1,000 different types of bats worldwide, with over 70 species in southern Africa. They are one of the most diverse groups of mammals, yet one of the least known or understood.
There are two main types of bats: those that eat fruits and those that eat insects. The former are generally quite large (up to 1kg) with big eyes, while insect-eating bats can be nearly as small as butterflies. Some of the insect-eating group also feed on small animals, such as fish, frogs, mice and birds.
There are many misconceptions about bats, such as the belief that they are blind, hence the saying ‘as blind as a bat’. This is not true at all; all bats have eyes and can see, although their eyes are best adapted to night vision. In fact fruit bats have good sight and use it to find food at night.
Insect-eating bats can also see, although their eyes are small and sight is not their most important sense. They mainly use echo-location to find their way around; this means they send out sounds which bounce off objects, and the echoes are detected using their sensitive ears. This provides an audio picture of their surroundings and enables them to fly around without bumping into things, and also to detect night-flying insect prey such as moths.
There are also beliefs that bats attack human beings and suck their blood. In fact, the only bats that suck blood are the vampire bats found in Central and South America. Bats do not attack humans if unprovoked and are gentle, non-aggressive animals.
There is a common belief in Africa that bats cannot fly during day time. In fact, bats can fly during the day just as well as we can walk during the night, and even better. But they do not do so normally, because they are sleeping. During the day bats sleep in dark, secluded places, such as in trees, caves or roofs, or under bridges or eaves of buildings.As soon as it begins to get dark they leave their roosts and set off into the night to feed.
In Africa, as in many other parts of the world, bats are often associated with witchcraft. However, in some places such as China, Cuba and the Pacific Islands, they are regarded as good luck charms.
In spite of bats having a lot of negative myths associated with them, they play important ecological roles. Fruit-eating bats carry out two important roles in the ecosystem: seed dispersal and pollination. They feed largely on fleshy fruits such as guavas, mangoes, bananas and wild fruits. They have been shown to be one of the major contributors to reforesting deforested areas, through seed dispersal.
Some also eat nectar and play a vital role in pollination of many plants, such as baobabs, sausage trees and many others. Without bats many plants would not be able to reproduce. Flowers pollinated by bats are usually large, white and open at night; some 300 tropical plant species in Asia and Africa depend on bats for pollination or seed dispersal. Insect-eating bats are the main predators of night-flying insects, feeding on various types of moths, beetles, mosquitoes and other insects. Theyplay the important role of keeping down insect numbers, including major crop pests and disease carriers. One bat can consume up to 5,000 mosquito-sized insects in a night. They are,therefore, very important to people.
In spite of the negative beliefs, bats bring good luck by helping control harmful insects and assisting in the pollination and seed dispersal of plants. Our environment depends on them, and so do we.