Physical characteristics

Body size of fruit bats, flying foxes, rousettes, tube-nosed bats, and blossom bats ranges from small (around 0.4 oz/12 g) to large (42.3 oz/1,200 g). They have dog-like faces with long snouts, which is the reason that some species are called flying foxes. Fruit bats differ in a number of features from the small insectivorous bats of the order Microchiroptera. Fruit bats are primarily visually oriented and have large forward facing eyes that give them depth perception. The retina contains cones for color vision. These bats have good daytime and nocturnal vision, but they are inactive in complete darkness. Except for the rousette bat, fruit bats do not echolocate. Consequently, most have a simple and relatively small external ear without a tragus. The sense of smell is also well developed in fruit bats. All fruit bats have claws on the first digit (thumb) and, unlike microchiropterans, most have claws on the second digits of the wing skeleton. Wings tend to be broad. These bats do not fly as fast as microchiropterans nor

Madagascan fruit bats (Eidolon dupreanum) flying at dusk. (Photo by John Vissor. Bruce Coleman, Inc. Reproduced by permission.)

do they perform the aerobatics of their relatives. They do travel long distances and have good hovering ability; some are even able to fly backwards. The wing is mostly devoid of fur. The wing membrane of one genus extends to the vertebral column creating a naked back. The tail is short, vestigial, or absent altogether. The uropatagium, a segment of membrane between the legs that helps provide lift, is not present in those species with a reduced or absent tail. The legs are splayed to the side like a reptile rather than underneath the body like other mammals. The hind paws are completely clawed. They are used predominantly for hanging upside down and, in conjunction with the clawed thumb, are used for climbing in trees.

The number of teeth is variable and ranges from Rousettus with a dental formula of (I2/2 C1/1 P3/3 M2/3) X 2 = 34 teeth, to Nyctimene and Paranyctimene having a dental formula of (I1/0 C1/1 P3/3 M1/2) X 2 = 24 teeth. The teeth of other species are intermediate in number: 32, 30, or 28 teeth in total. The incisors are small, canines are always present, and the cheek teeth (premolars and molars) tend to be flat and wide, suitable for crushing soft fruit. Tongues are sometimes long and mobile, especially in the nectarivorous species. In fruit eating species the tongue is used to crush food against the transverse ridges of the palate (roof of the mouth). In some species, such as the hammer-headed fruit bat, these ridges are highly developed.

The most common pelage (fur coat) color is dark brown, but this is highly variable. The ventrum (the belly side) is often a lighter color, such as off white or yellow.

Sexual dimorphism is often present. The most common difference between males and females is body size, but males may also differ in pelage patterns, especially on the head. Other male characteristics are hair tufts on the shoulders (epaulettes) and large pharyngeal sacs in the thoracic region.

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