Bats: Creatures of the Night

 Few mammals are as shrouded in fear and superstition as bats. In western culture, bats are regarded as symbols of doom and darkness and associated with horror stories in the Dracula tradition. Common fallacies are that bats are blind, a sign of death and will entangle themselves in people's hair. Undoubtedly, some of this fear stems from an unfamiliarity with these mammals. In fact, bats are among nature's most fascinating animals. They display a number of remarkable adaptations for their unique life-style.

Bats are flying mammals. Like all mammals, they have teeth and a body covering of fur, they give birth to live young and nurse their young with milk. However, bats are the only mammals that possess wings and the ability to fly. A bat's wing is quite different from a bird's wing, consisting of a membrane of elastic skin stretched across the bones of the fingers and hand. The scientific name for bats, Chiroptera, is a Greek word that means "winged hand".

Scientists recognize some 950 species of bats. They occur on all continents except Antarctica but the majority live in tropical regions. Their food habits are amazingly diverse. Most are carnivorous and about three-quarters of the known bats eat insects and other invertebrates. In the tropics, several bats are adapted to prey on vertebrate animals such as fish, frogs, lizards, birds and small mammals. The infamous vampire bats of Central and South America feed exclusively on the blood of mammals and birds. Other tropical bats are specialized to eat fruits, nectar and pollen of flowers. Although most bats are small, the flying fox, a fruit-eating bat, weighs as much as a kilogram and has a wingspan of two metres.

How bats navigate in total darkness is a question that has long intrigued man. As far back as the 1700s it was speculated that bats somehow saw with their ears, using a mysterious "sixth sense". We now know that this sixth sense is sonar or echolocation. Bats produce high-pitched beeps or clicks and listen for the echoes of these sounds as they are reflected off objects. Most of these sounds are a higher pitch than a human's range of hearing. This sonar system is highly sophisticated; it enables bats to avoid obstacles and even track flying insects.

With 17 species, British Columbia has more bats than any other part of Canada. We have none of the exotic tropical species, but our bats have managed to cope with the Canadian winter, a season of cold temperatures and few insects for food. Some of our bats avoid winter by migrating elsewhere; others hibernate in caves or old mines.

Bats have a long history of persecution. However, man has become increasingly aware of these unique animals and there is growing concern about the impact of pesticides, disturbance and habitat destruction on their populations.

David Nagorsen
Mammal Curator
Royal British Columbia Museum

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