Everything You Need to Know About Bats

They are fascinating creatures and an important part of the environment. Active at night bats are known for their powered flight. 

A Field Guide to the Bats of Sri Lanka by Prof Wipula Bandara Yapa sponsored and published by Dilmah Conservation is a book that explains everything you need to know about bats. 

In 1995, Prof Yapa initiated an ecological survey on the distribution of bats in Sri Lanka, which was one of the most detailed surveys carried out in Sri Lanka in recent times. His research expands to many areas such as breeding habits, roosting ecology, migration, social behaviour and pathogens of bats.

“Bats are mammals; and just like humans, they give birth to live young, nurse them with milk and sometimes even carry them when they go in search of food. They are also a fascinating group of animals and in fact, almost everything about bats is so extraordinary and unique, setting them well apart from all other mammals,” Prof Yapa says in his book.  

For example, they are the only group of mammals he says capable of sustaining powered flight. “For this, their forelimbs are modified to form a wing, which is so different from that of birds. The bat wing is a membrane which covers the hand and also the sides of the body. Bats have also developed an effective orientation system which involves the use of sound signals for perceiving the environment, the process which is known as echolocation,” Prof Yapa explained.

Although some other groups of vertebrates such as oil birds, whales and certain species of shrews are known to echolocate he says echolocation in bats is far more superior and advanced than the rest.  “These two specialisations, namely the evolution of flight and echolocation in bats, are most probably the main parameters in the diversification of feeding and roosting habits, reproductive strategies and social behaviour of bats,” Prof Yapa said. 

He added that bats have been able to exploit many ecological niches that were inaccessible to other groups of mammals, making them a very successful group of mammals. 

“So far, over 1,200 species of bats have been recorded, amounting to roughly one-fourth of the total number of mammals recorded at present. Thereby, they are the second largest mammalian order (next to rodents) in several species and probably exceed all other such groups in overall abundance. They have successfully colonised almost every continental region on the earth (except Antarctica), as well as many oceanic islands and archipelagos,” Prof Yapa explained. 

Their widespread distribution and he says, the unique specialisation in morphology, physiology and behaviours have led to various feeding habits, including feeding on fruits, nectar, leaves, flowers, pollen, insects, fish, other smaller vertebrates and even blood.

“Bats are believed to have evolved before early Eocene, 50 million years ago, as a complete skeleton of a bat, Icaronycteris index was found from an early Eocene site. This is the earliest known fossil record of a bat. The skeleton was assigned to the suborder Microchiroptera based on the structure of the forelimb and the morphology of the upper molars. The first true Megachiropteran with dentition adapted to a fruit-eating diet was found much later, in the early/middle Miocene epoch about 20 million years ago,” Prof Yapa explains.

The book explains that bats are a group of highly social animals and are gregarious, which means they live in large congregations and form the largest known mammalian congregations, some of which exceed several millions of individuals. 

“However, all bats do not live in such groups and many species live in smaller groups. In species that are considered “solitary”, the mother raises her young alone. The mother and her dependant young (generally a single pup) are the basic social unit of bats, and depending on the species, this may range in size from dozens of individuals to millions,” Prof Yapa said.

Generally, many species of bats give birth to a single pup in one breeding season he says although twinning is also occasionally seen at least in some species. In Sri Lanka, twinning has been observed in a few species such as Pipistrellus tenuis, P. ceylonicus and Scotophilus heathii.

Dilmah Conservation was initiated in 2007 by Dilmah to incorporate environmental conservation efforts into the Merrill J Fernando Charitable Foundation, which focuses on social justice. Dilmah Conservation works towards the sustainable use of the environment in partnership with various governmental and non-governmental organisations. The pledge made by late Dilmah founder Merrill J. Fernando to make business a matter of human service is deeply ingrained in the work carried out by Dilmah Conservation.

Read the article on Ceylon Today by Risidra Mendis: https://ceylontoday.lk/2023/12/18/everything-you-need-to-know-about-bats/