BATS (CHIROPTERA)

2 South African sub-orders: Fruit-eating bats and insectivorous bats.
No blood-eating bats in South Africa !

They represent 1/4 of the mammalian species.
They are the only mammals that are capable of sustained flight (not gliding but flap their wings)

Insect eating bats: 6 families; 68 South African species
Fruit eating bats: 8 South African species

Characteristics of Bats:

• Wings made up of skin, elastic tissue and muscle fibre. Any holes in wings heal within few weeks and broken finger bones mend quickly.
• They have a mechanism that looks digits of hind feet in place preventing them from falling.
• Well-developed sight, senses of hearing and smell.
• They have incisors, cannines, premolars, molars. The crow of molars are flattened in fruit-eating bats and insect-eating bats have molars with sharp crests.
• 1 clawed thumb
• Tail is very variable
• Skin area is proportional to the volume of the body; so a large amount of heat is lost, but is compensated by an intense feeding, sleeping in clusters and some bats by hibernating.

FRUIT-EATING BATS

• Important role in maintaining woodland savannas and forest areas. Some trees rely on fruit bats for pollination, whereas many trees rely on them to disperse their seeds (sausage trees). Meals are digested fast (<1 hour) and can be excreted in flight..
• They are larger than insectivorous bats. They have elongated muzzles and tubular pointed ears, 2 claws on each wing to clamber in trees and handle food.
• They have also large eyes to navigate at night. Not echolocation
• Only the Egyptian fruit bat has a basic echolocation, using sound produced by tongue-clicking
• The monotonous pinging of male epauletted fruit bats occurs after they have fed. Territorial males use this vocalization to advertise their presence to females, to demarcate their territories.
• Females give birth to 1 pup per season, in summer. She carries the young on her nightly excursion.

INSECT-EATING BATS

• Echolocation or sonar: ultrasonic sounds produced in animal's throat and projected forward, at a rate of 10 or more pulses per second. Pulses received by ears and intensity + character are interpreted by the brain. A typical bat's echolocation pulse sweeps between 45 000 and 90 000 Hz, above our level of hearing !
• They consume 25% or more of their own body weight in insects each night.
• Some hibernate.
• The Mauritian tomb bat migrates to tropical regions during winter.
• They can live for 25 years or more.