There is a common cliché I hear all the time: I’m as blind as a bat!
As a specialist bat carer I can’t help but cringe every time I hear this spoken aloud. When I bother to question the speaker I am interested to find that most people truly believe that all bats are blind. When I tell them of the amazing eyesight of some of the mega bat species, such as the Grey-Headed Flying-Fox, people are astounded. This has led me to want to educate people on the kinds of bats they might find around them in daily life, and the vast difference between micro bats and mega bats.
Because bats are nocturnal there are a lot of myths and even fears associated with them. These creatures are however, extremely intelligent, fascinating and some are as affectionate as your dog or cat. Bats have been given their own scientific classification Chiroptera, which is based on a Greek word meaning ‘hand-wing’, as the structure of their wings looks very much like an over-sized hand covered with membrane. Bats are the only flying mammals in the world. There are many different species of bats, but all are classified as either a Micro bat (microchiroptera) or Mega bat (megachiroptera).
Micro Bats Use Echolocation for Hunting Food.
Micro bats are those little flying creatures you spy out of the corner of your eye in the dusk, night and dawn. Micro bats mostly eat flying insects such as mosquitoes, although some species are known to eat frogs, fish and other small creatures. Some micro bat species are quite large and others are as small as a moth. The common cliché about bats being blind comes from these bats, as they primarily use echolocation to find their food. However, even these bats are not truly blind, as they do use their eyes like all mammals. But their eyesight is not very well developed so instead they have very large ears, and have developed echolocation for navigating and for finding food.
Echolocation is the ability to pick up sound waves in the environment, in particular the tiny, high pitched sound waves created by insects flying around at night. Sound waves are the moving patterns of fluctuations in air pressure. As the air pressure changes, it pushes surrounding air particles out and then pulls them in again. This pushes and pulls the particles next to them and so on and on. The frequency of these fluctuations in air pressure determines the tone and the pitch of the sound waves.
So basically, a micro bat will emit sound waves that bounce off objects around them. They make a sound and then listen carefully to the echoes that come back. These sounds are so high pitched they tend to be out of range of human hearing, but they allow micro bats to hunt for insects in the dark. A micro bat’s ability to use echolocation is so attuned, that they can determine all the objects around them using sound waves. They can determine the size and shape of everything flying in the night sky!
How Do I Tell a Mega Bat from a Micro Bat?
Mega bats are like their name, a lot bigger in general then micro bats, so this is the first point of difference. However, this is not always true, as in the case of the very small Blossom Bat, who is also classed as a mega bat. The main differences between mega and micro bats are physical features, and staple foods.
Mega bats eat fruit, pollen and nectar from flowering trees. They do not eat insects like micro bats. The mostly commonly known mega bats are the Flying-foxes or Fruit bats, which are found in the more tropical regions of the world such as Asia, South America, Africa and Australia. These bats live in large colonies or camps in the upper levels of forest canopies, usually near a source of running water. Fruit bats tend to be nomadic and can fly quite far during a night’s foraging for food. Micro bats, on the other hand, usually have a small range and firm territorial boundaries. If you find a micro bat in your backyard, it probably lives right there, whereas a mega bat could have flown 25km to reach the fruit tree next to your house.
Unlike micro bats, mega bat species have a well-developed visual cortex and very good eyesight. These bats have large eyes and a similar visual structure to human eyes. They can see well enough to spot fruit at night from great distances above. Mega bats also control their own body temperature and do not hibernate, unlike many species of micro bats.
A Few Other Differences
There are many different species of micro bats and they all have different staple foods, habitats and lifestyles. Some species are solitary; others live in large groups or colonies. Some micro bats live in caves, others in hollows in tree trunks or underneath the bark of particular trees, others will prefer the roof of your house! If you have bats in the house, they are most definitely micro bats.
Mega bats only live in large groups and will fly out each night to forage for food, then return to a camp or colony to rest and sleep during the day. While micro bats usually only live with the same species, mega bats will share colonies. In some areas of Australia, you will find up to 3 different mega bat species sharing the same camp.
Up close, micro bats and mega bats look very different. Some people would say that mega bats are more attractive in appearance, however this is all in perceptive! Mega bats have very large eyes, dog-like faces, no tail and are furred on their bellies. Micro bats can vary greatly in appearance depending on species, but are generally not furred underneath, have mouse-like bodies and very prominent facial features; such as tubular noses, large nose-leaf above the nose, large ears. Micro bats lack the claw at the second foe of the forelimb and often will have a tail.
All species of bats are valuable creatures in their local ecosystems and play an important role in the environment. In many countries, native wildlife is protected by law and no attempt to remove bats should be undertaken without proper authorisation. If you find an injured bat, please contact your local wildlife group.
References:
- How Stuff Works, Website, Copyright How Stuff Works Inc, 1998-2011,
- The Columbia Encyclopedia, Official Website Sixth Edition | 2008
Nina Boddenberg - Nina is a writer from Australia, who is currently building her own home and planting a large organic and permaculture garden. Nina ...
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