Over 1,200 different species of bat exist, which means they account for around one-fifth of all mammal species. Although they have a bad reputation, they're extremely important to humans as they keep insect populations down and help pollinate plants. They have a range of adaptations that help them survive and make them the unique creatures they are.
Bats have a variety of skeletal adaptations that allow them to fly. Like birds, they have reduced and shortened bones, so that they're light enough to take to the air. As mammals, their distant ancestors would have been flightless. Bats' wing membranes are supported by long bones, which actually are highly elongated fingers, which evolved over a long period of time to allow them to fly. In fact, Chiroptera, the scientific name for bat, means "hand-wing."
Roughly 30 percent of bats -- mostly megachiroptera or fruit bats -- have decent night vision. However, the remaining 70 percent still hunt at night, and must be able to maneuver around and catch their prey without technically being able to see. The solution to this is sonar, also known as echolocation. Bats emit pulses of an extremely high-pitched sound -- too high for the human ear to detect -- and wait to listen back for the echoes the sound produces when it bounces off nearby objects. This allows them to navigate and also to locate their food.
Bats are nocturnal creatures, which means they're active at night. This is a useful adaptation for them, as flight requires a lot of energy and could be too tiring for them during the day. Their thin, black wing membranes may cause excessive heat absorption in daylight hours, which could lead to dehydration. In addition, fewer predators are around to threaten bats at night and, for those bats who eat insects, a much larger amount of prey to catch.
Different species of bats vary when it comes to eating habits. As such, there are a range of different adaptations when it comes to feeding. For instance, frog-eating bats are able to pick up on low-frequency calls that frogs make to locate them and can even tell the difference between edible and poisonous frogs just by their call. Lesser long-nosed bats are nectar eaters, and have elongated noses to allow them better access to flower nectar.
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