March 25, 2009

Study finds not all bats land the same way

A U.S.-led study has documented for the first time how bats land and the scientists discovered that not all bats land in the same manner.

The Brown University-led researchers said their findings offer new insights into how the Earth's second-largest order of mammals evolved.

Daniel Riskin, lead author of the study, said the scientists studied the landing approaches of three species of bats -- two that live in caves and one that roosts in trees.

The team filmed each species of bat as it swooped toward a latticed landing pad and landed on it. Cynopterus brachyotis, a tree-roosting bat common in 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 with an impact of more than four times the species' body weight.

The team then focused on two cave-roosting species, Carollia perspicillata and Glossophaga soricina. Those bats, common in Central and South America, approach their landing with a vertical pitch and, at the last instant, yaw to the left or right before grasping the landing pad with just their hind legs. That landing, said the researchers, is much gentler than that of the tree-roosting bats.

The study that included scientists from the University of Southern Denmark, appears in the in the journal Ecology and Evolutionary Biology.