Volume 29, Issue 1, Spring 2011

Bat Faces

An amazing diversity of features

BCI Members are familiar with the endearing appearance of typical bat species: the compact faces of most insect-hunters, the canine-like look of fruit bats and flying foxes, and pollinators' long snouts that let them reach deep into flowers for nectar. But the 1,200-plus species of bats offer an amazing diversity as bats have adapted to countless habitats, conditions and food resources. Many bats display unusual, occasionally even bizarre, faces.

For a sampling of unique bat species, we asked members of BCI's new Science Advisory Committee to identify some bat species with particularly intriguing faces. Their choices:

Common vampire bat
Desmodus rotundus

One of only three bat species that feed on blood (and the only one that favors mammals), the common vampire of Latin America is well adapted for its diet. The short, flat face lets it get up close and personal to prey. Early naturalists asserted incorrectly that the small, triangular nose leaf was a blade-like appendage used to pierce the flesh. It is, in fact, soft, pliable and packed with heat sensors for locating blood-rich areas in the skin. Vampire bats have a prominent groove on their lower lip where the tongue protrudes as they lap the blood at the site of the bite. (Charles Rupprecht)

Hammer-headed fruit bat
Hypsignathus monstrosus

This distinct face is found only among male hammer-headed fruit bats; females look like rather typical fruit bats. But males of this African species have a hairless, split chin and a very large head, with an anatomy that's designed to produce loud, honking calls. Female hammer-heads apparently find these resonant sounds very attractive and stimulating. (Charles Rupprecht)

Greater false vampire bat
Megaderma lyra

Greater false vampires are large bats with very prominent ears and a nose leaf that helps to focus echolocation calls. These Old World gleaning bats can detect and capture prey in complete darkness. They also use specific echolocation calls to communicate with one another regarding varied interactions, including courtship. (Charles Rupprecht)

Malayan tailless leaf-nosed bat
Coelops robinsoni

Like all bats in the family Hipposideridae, Malayan tailless leaf-nosed bats have a complex nose leaf that is presumed to play a role in focusing echolocation signals, which are emitted through the nose. In this genus, the front leaf is split, creating two lobes that move a bit like a moustache when the bat is echolocating. (Tigga Kingston)

Lesser naked bat
Cheiromeles parvidens

This bat of Indo­nesia and the Phil­ip­­pines is not well known, but it has the typical smooth muzzle and characteristic  "smile" of free-tailed bats. A large hunter of flying insects, it has no fur, just a covering of fine hairs. (Tigga Kingston)

Wrinkle-faced bat
Centurio senex

A fruit-eating bat that ranges from southern Mexico to Colombia and Venezuela, the wrinkle-faced bat's peculiar morphology is not well understood. The grooves and flaps of its face may help shape its echolocation beams. A ­recent study shows that, because of the unusual shape of its skull, this bat is capable of the strongest bite-force of any species in its family (Phyllostomidae). That powerful bite presumably allows this bat to feed on very hard items, possibly seeds. (Rodrigo Medellín)

Banana bat
Musonycteris harrisoni

The nectar-feeding banana bat is an endangered species that is losing its habitat to tourism development along the Mexican coast. In proportion to its body, it has the longest skull of any bat, and its tongue can be extended more than three inches (76 millimeters) to take nectar from very deep flowers. (Rodrigo Medellín)

Common noctule
Nyctalus noctula

The common noctule has very conspicuous buccal glands in the corners of its mouth that secrete a white, fatty material, the function of which remains unclear. Equally conspicuous are the nasal glands, which explain the bulbous nose. These are pushed into the wing during grooming and their secretions help to make the noctule one of the most pungent of European bats. (Paul Racey)

Eastern sucker-footed bat
Myzopoda aurita

The eastern sucker-footed bat features conspicuous upper lips that hang over the lower jaw, although there is no known correlation between these unusual lips and the bat's diet of small moths and beetles. It roosts head-up in the partially unfurled central leaf of the traveller's tree of Madagascar, and recent research finds that the suckers that enable it to adopt this unusual roosting position don't actually suck – they work by wet adhesion. (Paul Racey)

Brown long-eared bat
Plecotus auritus

The brown long-eared bat is a gleaner that snatches insects from leaves and branches in European deciduous forests, where it often switches off its echolocation to listen for noises made by prey. When fully expanded, the bat's ears are almost as long as its body and collect very low-intensity sounds made by prey. The hearing of these bats is considered more acute than that of any other species. (Paul Racey)

Tube-nosed fruit bat
Nyctimene sp.

This rather striking bat is an apparently new-to-science species that was discovered on Papua New Guinea. Very little is known about it, but the tubes on the nose might increase the sense of smell. (Kate Jones)

Tube-lipped nectar bat
Anoura fistulata

The tube-lipped nectar bat, discovered in Ecuador in 2003, has what is believed to be the longest tongue relative to body length ever reported in a mammal. The tongue, averaging about 3.3 inches (85 millimeters), is up to 1½ times the length of the bat. It curls the tongue inside a special chest cavity. The tongue apparently evolved so the bat could take nectar exclusively from a long, tubular flower in the cloud forests of Ecuador. (Kate Jones)

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