Saturday, July 11, 2009

Bats In The Gold Coast

The Gold Coast has a huge colony of Fruit Bats that live in the gardens by the River.
I was walking along when I heard the screech of the bats in the trees.

Bats belong to the order Chiroptera (meaning "hand winged") and are divided into two suborders, Microchiroptera and Megachiroptera:-

(Microbats) are
small, mainly insectivorous bats which navigate and feed using echolocation.
It is believed that microbats evolved from a shrew-like ancestor being born blind and without fur. In Australia we have approximately 63 species of microbats, that live in a range of habitats including tree hollows, caves, roofs and walls of houses, and change roost sites often to avoid predation. These colonies can consist of a small number of animals or several thousand.
Microbats have a unique way of conserving the energy they need to sustain flight while feeding and echolocating. They are capable of going into what is called 'torpor' by lowering their body temperature which in turn lowers their breathing and heart rate. They can appear almost lifeless as they barely move and are cold to the touch. This happens frequently in colder months when food is scarce.

The system known as echolocation is a highly sophisticated method microbats use to generate information about their surroundings. It is achieved by emitting high frequency sound waves through their mouth and nostrils, and listening for the echo bouncing back from surrounding objects. These can be solid objects they are navigating around or tiny fruit flies they are hunting to eat. It is difficult to imagine how microbat brains interpret this information to form a perfect picture of their environment. For example, the echoes bouncing back can tell them the distance from their prey, the size, shape and even the speed it is travelling. The sound waves need to be high frequency to get the detail back they require, so is above our hearing range. There are some very elaborate facial features on microbats such as noseleafs that direct echolocations calls. It is truly an amazing feature and is the subject of a great deal of study. Different species have different frequency calls, thus specialised equipment known as bat detectors have been designed to record these calls and identify species.

There have been numerous articles about bats biting people and being pests.

Today I learnt that aborigines love to eat the fruit bats as they eat mainly fruit and their flesh is very sweet. Sounds nice.

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