How bats land at their daytime perches

March 21st, 2009 - 5:33 pm ICT by ANI  

Washington, March 21 (ANI): Studying the landing approaches of three species of bats, a Brown University-led research team found that not all bats arrive at their daytime perches the same way.
The researchers revealed that the study involved two species of bats that live in caves, and one that roosts in trees.
Their findings attain significance because they may offer new insights into how the second-largest order of mammals evolved.
Hanging upside down is what bats do. We”ve known this. But this is the first time anyone has measured how they land, said Daniel Riskin, a postdoctoral researcher in the Ecology and Evolutionary Biology department at Brown and lead author on a paper published in the Journal of Experimental Biology.
The researchers used sophisticated motion capture cameras in a special flight enclosure to film each species of bat, as it swooped toward a latticed landing pad and landed on it.
They observed that Cynopterus brachyotis, a tree-roosting bat common in tropical parts of southeast Asia, executed a half-backflip as it swooped upward to the landing site, landing as its hind legs and thumbs touched the pad simultaneously a four-point landing.
According to Riskin, the landing is hard with an impact force more than four times the species body weight.
As regards two cave-roosting species Carollia perspicillata and Glossophaga soricina, which are common in Central and South America, the researchers say that these bats they approach their landing target with a vertical pitch and then, at the last instant, yaw to the left or to the right executing a cartwheel of sorts before grasping the landing pad with just their hind legs.
The researchers say that the two-point landing is much gentler than the impact force exerted by the tree-roosting bats.
The cave-roosting bats have a landing impact force of just one-third of their body weight.
Given that about 1,200 recognized bat species exist across the world, Riskin was cautious about not drawing any grand conclusions.
However, he still said that the fact that the team has documented that bats land differently could open new insights into a species that makes up roughly one-fifth of all mammals on earth.
It’’s opening the door to how bats evolved. You can say that bats have been hanging upside down since they first evolved, and it has probably been one of the keys to their worldwide success, Riskin said.
The findings appear in the Journal of Experimental Biology. (ANI)

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