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This article is about mammals. For other bats, see bat (disambiguation).
Bats are flying mammals
in the order Chiroptera with forelimbs developed
as wings. Other mammals, such as flying squirrels or gliding phalangers, can glide limited distances, but only bats are capable of true flight. The name Chiroptera
can be translated as Hand Wing, as the structure of the open wing is very similar to an outspread human hand, covered in
a membrane.
Though the vast majority of bats are insectivorous, a significant number from both suborders, Megachiroptera and
Microchiroptera (see below), have developed the ability to feed on fruits and their juices. Some of the smaller species are
important pollinators of some tropical flowers. Indeed, many tropical plants
are now found to be totally dependent on them, not just as pollinators, but eating the resulting fruits and so spreading their
seeds. In addition, some bats prey on vertebrates. These bats include the
Leaf-nosed bats (Phyllostomidae) of central and South America, and the allied family Noctilionidae (Bulldog bats) that feed on fish.
Classification
There are two suborders of bats:
- Megachiroptera (megabats or fruit bats)
- Microchiroptera (microbats, echolocating bats or insectivorous bats)
Megabats eat fruit, while microbats eat mainly insects, and often rely on echolocation for navigation and finding prey. A handful of species,
the vampire bats, feed on blood.
It was once believed that megabats and microbats developed independently, and that the shared characteristics were the result
of convergent evolution. After numerous genetic analyses it
has been established that both groups have a common flying ancestor.
Little is known about the evolution of bats, since their small, delicate skeletons do not fossilize well. The oldest known bat
fossils are Icaronycteris, Archaeonycteris, Palaeochiropteryx and Hassianycteris from the
early Eocene (about 50 million years ago), but they were already very similar to modern
microbats.
Bats are usually grouped with the tree shrews (Scandentia), colugos
(Dermoptera), and the primates in
superorder Archonta.
- ORDER CHIROPTERA
- Suborder Megachiroptera (megabats)
- Suborder Microchiroptera (microbats)
- Superfamily Emballonuroidea
- Emballonuridae (Sac-winged or Sheath-tailed bats)
- Superfamily Rhinopomatoidea
- Rhinopomatidae (Mouse-tailed bats)
- Craseonycteridae (Bumblebee Bat or Kitti's Hog-nosed Bat)
- Superfamily Rhinolophoidea
- Rhinolophidae (Horseshoe bats)
- Nycteridae (Hollow-faced or Slit-faced bats)
- Megadermatidae (False vampires)
- Superfamily Vespertilionoidea
- Superfamily Molossoidea
- Superfamily Nataloidea
- Natalidae (Funnel-eared bats)
- Myzopodidae (Sucker-footed bats)
- Thyropteridae (Disk-winged bats)
- Furipteridae (Smoky bats)
- Superfamily Noctilionoidea
- Noctilionidae (Bulldog bats or Fisherman bats)
- Mystacinidae (New Zealand Short-tailed bats)
- Mormoopidae (Ghost-faced or Moustached bats)
- Phyllostomidae (Leaf-nosed bats)
Anatomy
The metacarpal bone and the second and fifth toe of the forelimbs are elongated, and between these toes is a membrane, called
"chiropatagium". The membrane extends from the toes to the body side and from there to the base of the hindlimbs. The entire wing
of a bat is called patagium. Many species also have a membrane between the hindlimbs enclosing the tails. This membrane
is the uropatagium.
The patagium is full of fine blood vessels, muscle fibres and nerves. When it's cold, the bats wrap themselves up
in their wings like in a coat. In warm weather they stir their wings in order to cool their bodies.
The thumb and sometimes the second toe of the forelimbs have claws, as do all five toes of the hindlimbs. The rear claws allow
bats to hang on branches or ledges. Bats are also able to move on the ground, but they are rather clumsy.
All bats are active at night or at twilight, so the eyes of most species are poorly developed. Their senses of smell and
hearing, however, are excellent. By emitting high-pitched sounds and listening to the echoes, the microbats locate prey and other nearby objects. This is the process of echolocation, a skill they share with dolphins and whales.
The teeth resemble those of the insectivores. They are very sharp in order
to bite through the chitin armour of insects
or the skin of fruits.
Reproduction
A newborn bat can cling to the fur of the mother and be transported, although they soon grow too large for this. It would be
difficult for an adult bat to carry more than one young, so normally only one young is born. Bats will often form nursery roosts, with many females
giving birth in the same area, be it a cave, a tree hole, or a cavity in a building. Two mammary glands are situated between the chest and the shoulders. Only the mother cares for the young, and
there is no continuous partnership.
The ability to fly is congenital, but after birth the wings are too small to fly. Young microbats become independent at the age of 6 to 8 weeks, megabats not
until they are four months old. At the age of two years bats are sexually mature.
Enemies
Small bats are sometimes preyed upon by owls and falcons. Generally there are few animals able to hunt a bat. In Asia there is a bird, the bat hawk, which
specializes in hunting bats. The domestic cat is a regular predator in urban areas; they may
catch bats as they enter or leave a roost, or on the ground. Bats will land on the ground for feeding, in bad weather, or due to
accidents while learning to fly.
The worst enemies are parasites. The membranes with all their blood vessels are
ideal food sources for fleas, ticks and mites. Some groups of insects suck exclusively bat blood, e.g. the bat fly. In their caves the bats are hanging close
together, so it is easy for the parasites to infest new hosts.
The following advice is only relevant to areas with endemic rabies.
Of the very few cases of rabies reported in the United States every year, most are
caused by bat bites. Although most bats do not have rabies, those that do may be clumsy,
disoriented, and unable to fly, which makes it more likely that they will come into contact with humans. Although one should not
have an unreasoning fear of bats, one should avoid handling them or having them in one's living space, as with any wild animal.
If a bat is found in living quarters near a child, mentally handicapped person, intoxicated person, sleeping person, or pet, the
person or pet should receive immediate medical attention for rabies. Bats have very small teeth and can bite a sleeping person
without necessarily being felt.
If a bat is found in a house and the possibility of exposure cannot be ruled out, the bat should be sequestered and an animal
control officer called immediately, so that the bat can be analyzed. This also applies if the bat is found dead. If it is certain
that nobody has been exposed to the bat, it should be removed from the house. The best way to do this is to close all the doors
and windows to the room except one to the outside. The bat should soon leave.
Due to the risk of rabies and also due to health problems related to their guano, bats
should be excluded from inhabited parts of houses. For full detailed information on all aspects of bat management, including how
to capture a bat, what to do in case of exposure, and how to bat-proof a house humanely, see the Centers for Disease Control's website on bats and
rabies .
Where rabies is not endemic, small bats can be considered as harmless. Larger bats can give a nasty bite. Treat them with the
respect due to any wild animal.
Cultural aspects
The bat is sacred in Tonga, West
Africa, England, Australia and
Bosnia, and is often considered the physical manifestation of a separable soul. Bats are closely
associated with vampires, who are said to be able to shapeshift into bats, fog or wolves. Bats are also a symbol of ghosts, death and disease. Among some Native Americans, such as the Creek, Cherokee and Apache, the bat is a
trickster spirit. Chinese lore claims the
bat is a symbol of longevity and happiness, and is similarly lucky in Poland and
geographical Macedonia and among the Kwakiutl and Arabs.
In Western Culture, the bat is often a symbol of the night and its forboding nature. The bat is a primary animal associated
with fictional characters of the night such as both villains like Dracula and heroes like Batman. The association of the fear of the night with the animal was treated as a literary challenge by Kenneth Oppall, who created a best
selling series of novels, beginning with Silverwing, which feature bats as the central heroic figures much in a similar manner as the classic
novel Watership Down
did for rabbits.
In the United Kingdom all bats are protected under the Wildlife and
Countryside Acts, and even disturbing a bat or its roost can be punished with a heavy fine.
External links
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