09 February 2015

Batting for bats

Bats are something that usually inspire fear or create revulsion among all (or most)of us. I did not really spare them much thought except on our long walks on a disused taxi track where we used to see huge bats (recognisable due to their typical wings) flying across the runway. More recently a group of bats relocated to a tree outside my balcony which is when I took a keen interest. Would they be dangerous? Will they accidentally enter my home? And so on... Luckily they flew away before I hit the panic button.

Thus, I could not miss on a 'bat spotting walk' organised by Virasat Pune conducted by Dr Vishakha Korade who has done her PhD in Bats! Here is what I learnt. 

Trees, bat, bats, vampire
A colony of bats seen handing from Kinhai trees

Fruit bats (aka Flying fox) are vegetarian and this was the species that was near my home. (This is what I inferred from some of her answers to my queries). They roost on tall trees with sparse foliage (we saw them hanging upside down on Eucalyptus and Kinhai trees) and fly out at dusk and return at about 5AM. They feed on fruits (specially of the Ficus genus) and other plant parts as well except roots and stem. The digestion process in bats increases the chances of germination of the seeds in the fruit they eat. These seeds are disbursed in their excreta hence the bats are an important part of the ecosystem. They also help pollinate some plants species (about 400 e.g. Kigelia africana, Adansonia digitata). According to Dr Korade, while many urban people fear bats, people in villages refer to them as Laxmi (as in the goddess)! I guess they understand the position of bats in the ecosystem more than us city folk! Fruit bats have fair vision and find their food etc using their eyesight and olfaction.Contrary to belief, fruit bats do not use eco-location.

Smaller insectivorous Evening bats (called पाकोळया in Marathi) produce twins about thrice a year but they are lost to predation and the total number often does not increase. These bats look like swifts and can be seen about 15 minutes after sunset. They may share a shelter with swifts too. Evening bats use eco-location to find their food.

There is a species called Vampire bats that feed on blood (usually of cattle). They secrete an anticoagulant when they bite the animals and then feed on it. These can also regurgitate the ingested material to feed young ones left behind or those unable to fly out. There is a type of 'false vampire bat' that is found in Asia.
Bats have a weak pelvic girdle and lower limb muscles and do not 'stand' on legs like humans. Being mammals, they give birth to live young ones. Fruit bats produce one offspring every year (after about a two month gestation). The young ones may be carried on the bellies for some time. Bats are a reservoir of many types of virus and may be carriers of Rabies, Ebola. They usually are not dangerous to humans but may spread disease if people consume plant produce contaminate with bat fluids (e.g. toddy collected from trees). Their bodies are geared for an upside down life. Here is a link to some info about the bodies of bats.

In recent times, bats may have gained some popularity due to the popular book series by Stephenie Meyer. However I was pleasantly surprised at this session to see kids ask several intelligent questions. I guess India does have a bright future, provided they stay and work here of course not fly off to foreign lands... 

The number of fruit bats in the colony we saw is dwindling which can be a cause for alarm as an important member of the ecosystem will be lost. Loss of their habitat could be a reason. Indiscrimiate cutting of trees has to be stopped.
Its important to keep learning something new as its a big wide world and we would only have skimmed the surface!

What have you learned recently?


Madhu Shetty said...

Fascinating bat trivia! When we lived on plantations, bats would sometimes fly into our living room. Turning off all lights and leaving the doors and windows open usually helped them find their way back again. They seem scarier than they really are :-)

Archana said...

That was an easy way to let them out of the room. Thanks for sharing this experience! :)

Archana said...

Update: Came across this article from the National Trust that has described two sad instances when bats were killed - one in in the 1960s in Israel and one in Guam. Do read http://www.nationaltrust.org.ky/index.php/fruit-bats-the-real-story