Bats are small, nocturnal mammals that are shy of humans, although there are many bats in our environment most people never come into contact with them and are unaware that the night skies are often filled with the sounds made by these fascinating creatures. There are over 1400 species of bats in the world, the second most diverse group of mammals with rodents taking first place. Their size varies greatly between species, ranging from the large flying foxes of Australasia with wingspans of up to 1.6 m to the tiny pipistrelle bats which weigh less than a R2 coin.

We are lucky enough to have 73 species of bats in South Africa, but unfortunately, two-thirds of the species assessed for the South African Red Data Book (a list showing how close to extinction a species is) are listed as “Near Threatened to Critically Endangered”. In KwaZulu-Natal three species are of special concern: the Short-eared Trident bat is known from only one colony in the north of the province. Rendall’s serotine is also known from only one place, and the Large-eared Giant Mastiff bat is found only in the greater Durban area and, so far, only in house roofs.


Bats in South Africa can be separated into two groups: the bigger fruit bats and the smaller insectivorous bats. Fruit bats have long noses typical of animals with a good sense of smell, big eyes (and thus excellent eyesight), and no tail. They are never found IN roofs, although they are often found around houses, typically in trees but sometimes hanging on the eaves. Insect bats are smaller – some can sit quite comfortably on the end of your thumb and often have strange face structures which signify their incredible ability to navigate using sound, a process known as echolocation. All insect bats have tails. Nearly all bats eat either fruit or insects – a handful of species eat other things such as scorpions, small fish, and frogs. Only the vampires of central America thrive on blood. Vampire bats have suffered much bad press owing to superstition and entertainment media, but are very small (less than 50 g) bats with a strong social structure and they are not able to swarm and kill large prey and humans!

Being mammals, bats have fur, bear live young, and the mothers feed the babies milk as any mammal mother. Bats usually have only one baby a year, although in the warmer parts of this country in good years some mothers may have another in the second half of summer. Baby bats are called pups and are born pink, hairless, and with small stubby wings. They cannot fly for the first few weeks of life and at this time are unable to leave their roosts.  Fruit bat mothers generally carry their young with them at night; insect bats usually leave them in a safe roost and return at intervals to feed.

With only one baby a year, and with a low survival rate due to the immense amount of skills they need to learn, bats have some of the slowest reproductive rates of any small animal. To balance this, bats have also the longest life spans of any small mammal and there are several records of bats living longer than 40 years.


In Africa, all insect-eating bats, and one species of cave-dwelling fruit bat, the Egyptian Fruit bat, communicate and navigate using echolocation. This is done by listening to echoes bounced back from high frequency, ultrasonic clicks and squeaks emitted through the mouth or nostrils.The ultrasonic calls emitted by bats range in frequency (‘pitch’) from 20 to 210 kilohertz (one kilohertz, or 1 kHz, equals 1000 vibrations per second) and are generally inaudible to humans (who hear sounds of up to 20 kHz). Even though we cannot hear them, bats’ echolocation calls vary considerably in amplitude, with ‘whispering bats’ having soft calls and bats like horseshoe bats having very loud calls, with amplitudes comparable to the sound of a jackhammer at close range.The echolocation system of bats is vastly more efficient than any man-made sonar system. The American Navy is conducting ongoing research into the echolocation system of bats to model their underwater sonar systems more closely on that of bats.Today we can use bat detectors to convert the higher pitched bat sounds into signals that we can hear. This provides us with a window on the fascinating lives of bats.

Most bats are highly social: they live in stable colonies and many retain life-long bonds with their mothers. Colony sizes vary from the many thousands of cave-dwelling long-fingered bats to sheath-tailed bats, which roost singly or in mother-daughter pairs. Occasionally adult male bats live alone.

Bats are very clean animals: they groom themselves meticulously using their hind feet as combs. They carry very few parasites, all of which are specialized for their bat hosts: none have been known to transfer themselves to humans and they carry no known disease.

Hibernation and Torpor

The insect-eating bats have a very specialized ability to save energy when food is short or the temperature is very cold: they can “reset” their metabolic rate in a process known as torpor. A bat undergoing torpor chooses a safe roost site and in effect falls into an extremely deep sleep. Its heart rate slows, its breathing rate reduces, and its body temperature drops. When the bat “sleeps” like this throughout winter it is known as hibernation. A torpid bat moves very slowly, as if it is moving through syrup, and before it can fly it has to warm itself. Many of our insect bats warm slowly throughout the afternoon to be ready to fly in the evening; a bat which is disturbed during the day has to warm itself rapidly by shivering. Disturbing a hibernating bat can cost many their lives, as the emergency warming process is very expensive energetically. Each warming costs the equivalent of 8 to 30 days of fat reserve. If the bat runs out of its fat reserves before winter is over and the insect numbers have returned, it may starve.

The importance of bats to our environment cannot be overemphasized. Because they are small and nocturnal the impact they have is largely undocumented, but the world as we know it would be very different without our bats.

Bat numbers the world over are dropping due to human intolerance, pesticide misuse, and the removal of indigenous vegetation

However, they do not have to be a “problem” to humans, with the correct knowledge, we can learn to appreciate the role they play in the environment and the beneficial impact on our lives without impacting theirs.

Insectivorous Bats

Insect-eating bats are the major predators of night-flying insects, which include most crop pests, moths, and mosquitoes. In the USA it has been estimated that the free-tailed bats of south-central Texas eat 1 000 TONS of insects per night, mostly corn earworm and tobacco budworm moths, and fly to heights of up to 3,000 meters to do it. In this country, no study has yet been undertaken on the impact of our bats, but they are probably eating similar amounts.
The droppings of insect-eating bats are known as guano and can be used as an excellent fertilizer.

Fruit Bats

Fruit bats rarely eat fruit while hanging due to the fruit’s weight. They will take a mouthful of fruit and fly to another site to eat it. After chewing the fruit and swallowing the juice, they spit out the seeds and pulp. While this habit annoys many patio owners, it is essential for the regeneration of forests. It has been estimated that 95% of the new trees in tropical rainforests grow from the seeds dropped by the bats. Fruit bats are also the pollinators of many African trees, including the Baobab and the Iroko. Fig trees are a favourite, so be sure to keep an eye out when close to them.