‘Chiroptera’ – Thailand’s Mysterious Night Flyers

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‘Chiroptera’ – Thailand’s Mysterious Night Flyers
‘Chiroptera’ – Thailand’s Mysterious Night Flyers

Bats, or Chiroptera, are the second largest order of mammals after rodents, representing about 20% of all classified mammal species worldwide, with about 1,240 known bat species.

tinents except the Antarctic. The largest species of bat is the Australian ghost bat, which can reach a body length of 14 centimetres, a span of 60 centimetres and a weight of 200 grams. The vast bat diversity around the world appears to be found located in the tropical rain forests of South East Asia. In Thailand, at least 140 species in 11 families and 45 genera of bats have been documented. Bats are the only mammals beside the birds and the only vertebrates, which can actively fly. The seeds of many plant species are spread by bats. The oldest bats fossil is dating back to 50 million years. The evolution of bats began about 56 million years ago and ended about 33.9 million years ago.

About 70% of bat species are insectivores (insect eaters) most of the rest are frugivores, or fruit eaters.

Bat species represent the most diverse group of Thai mammals. The current number of species seems to be underestimated. There are many complications in the reliability of species identification, monitoring and evaluation of this biodiversity with some species lacking supporting evidence. This means that identifying specific species, even those seen in large colonies is uncertain. The bats which have bcome an attraction as they stream from the Nayang Bat Cave near Cha-Am is one example. The smallest bat is the Peanut Bat, also known as a Bumblebee Bat, with a body length of three centimetres, a wingspan of 13 centimetres a weight of two grams. This is the most unusual of the species native to Thailand as the smallest mammal in the world, next to the Etruscan shrew. It was in 1973 that this species was discovered by the Thai mammal researcher Kitti Thonglongya near the Rver Kwai. Bumblebee bats live together in groups of 4 – 5 animals, and are only active after about 6 PM.

They never leave their caves through the main entrance but always prefer cave chimneys and cave columns as excursion openings which irritated many researchers. It is believed that this is a survival strategy in order not to fall prey to possible larger species, which usually fly through the main cave entrance. Their main hunting grounds are the bamboo forests near the caves. Their prey includes small flies, parasitic wasps and tree lice that live near the bamboo and tree tops at night. With their echolocation system, bats have developed a very complicated and effective method that allows them to find their way in the dark and hunt insects without using their eyes. Bats emit ultrasonic waves, which are reflected by objects as reflections. The individual echoes are picked up by the bat and put into the correct sequence.

The time differences allow the brain to sense the environment and thus locate how far a tree or insect is, and even at what speed and direction a prey animal is moving. Bats have a dense, often silky coat, which is mostly gray to brown or blackish colored and has no hairline. But there are also white and patterned species, in almost all species, the ventral side is also lighter than the back. Unlike other mammals, they have no wool hair, the fur hairs are speciesspecific and have small scales used to determine the species.

By Dr. George F. Grossniklaus

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