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The
order Chiroptera is divided into two suborders: Megachiroptera
(with a single family, Pteropodidae) and Microchiroptera
(with the remaining 17 families). Combined, the order
consists of 18 families, 192 genera and 977 species.
Chiroptera are distributed throughout the world except
in the coldest polar regions of the northern and southern
hemispheres above the tree lines. The fossil history
is from the early Eocene to Recent with some of the
oldest specimens occurring in Wyoming, United States.
Chiroptera
possess several unique characteristics that set them
apart from other mammals. Most notable is that they
can fly. Their limbs are highly modified for flight.
All digits except the thumb are elongated with fleshy
membranes stretched between. These membranes are actually
two layers of very thin, elastic skin. In most species,
the thumb, second digit and toes are clawed. In addition,
several of the vertebra are fused, the ribs are flattened,
and entire pectoral region is designed to support enlarged
muscles for flight. Chiroptera are heterothermic with
body temperature variances of between 41° C (106°
F) during flight to a hibernating and torpor temperature
of 2° C (36° F).
Studies
indicate that more than half of the species of Chrioptera
use echolocation to locate and identify items. Sounds
are produced through the mouth or nose and received
by the ears. In some species these features may be highly
specialized to enhance their echolocation abilities.
Sound is also used for communication.
The
feeding habits of the various Chiroptera species are
quite diverse. In general there are six primary diets:
insectivores, fruit eaters, flower feeders, vampires,
carnivors, and fish eaters.
Chiroptera
are highly social. Gathering in groups to rest and reproduce,
certain species form some of the largest aggregations
of all the mammals numbering into the millions.
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