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Chambers Wildlife Rainforest Lodges |
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'Bats' Order Chiroptera Bats are one of the successful groups of mammals of all time. Of the living mammals today, one fifth of all species are bats (Strahan 1998). Bats are the only mammals capable of true, sustained flight and this has enabled them to colonise many parts of the planet before other mammals. Subsequently, they are found all over the world. As with many groups of animals, there are many more species in the tropics. The ability of bats to fly is connected to a suite of physical features that are often their most distinguishing characteristics. The most obvious of these is of course the wing. Unlike birds, bat wings are actually stretched skin. It is an elastic membrane that stretches from the shoulders, along the arm, is supported by the elongated fingers, and completes the wing by reaching to the ankle (Strahan 1998). This design has certain consequences for the bat. While being efficient climbers, their hip arrangement restricts the movement and support of the hindlegs under the body (Strahan 1998), therefore they are rather clumsy on the ground, limited to scurrying along. This also means that when resting, all bats tend to hang rather than sit or stand. The arrangement of the bones and ligaments in the foot is thus that it does not require any effort to 'lock' onto a branch or ledge. The bat order is comprised of two major groups, the suborder of the Microchiropterans, and the suborder of the Megachiropterans. The former group includes the smaller insecteating, echo-locating bats that most people are familiar with, while the latter consists of the larger fruit and nectar bats that are found predominantly in the old world tropics. Because these two types of bats are so different, there has been some interesting debate over the last few decades as to whether they are even related. Bats in Australia There are at least 70 species of bats in Australia, with perhaps as many as 90 (Egerton 1997). This is almost a quarter of Australia's mammals. Despite this large proportion, they did not evolve here from the original Gondwana stock. Rather, they 'invaded' the continent relatively recently. Because they have the ability to fly as no other mammals can, they were able to colonise Australia millions of years ago when it was still quite a relatively remote island. Therefore, in contrast to Australia's marsupials, the bats of Australia are not seen as unique. It is generally agreed that bats colonised the Australian continent from South-east Asia, and this idea is confirmed by the similarity between the Asian and Australian bat fauna. The invasion was probably mostly via New Guinea and then by way of Cape York, as this is presently where most species are found (Strahan 1998). Thus, Australian bats are not seen as particularly unique and are considered closely related to their ancestral Asia stock. Nevertheless, of the numerous species found here about half are endemic to the continent (Strahan 199). |
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Chambers Wildlife Rainforest Lodges |
