Sticky Science: Why Some Bats Sleep Head-Up

A tiny bat that hangs out in Madagascar is an odd sleeper: Unlike other bats that hang upside-down, this one roosts head-up, and now scientists know why.

The sucker-footed bat, as it is known, likely sticks to surfaces with a sweat-like substance and would easily become unlatched if hanging upside down.

Called Myzopoda aurita, the sucker-footed bat is just 2 inches long (5 cm) and weighs a mere one-third of an ounce. They can be found clinging to the smooth inner surfaces of broad, fanlike leaves that furl up like tubes and are located high off the ground in a tree called Travelers Palm (Ravenala madagascariensis).

M. aurita is one of just six bat species known to snooze right-side-up, while the rest of the 1,200 or so bat species sleep hanging from their toenails.

Scientists have known from recent work that four of the head-up nappers, called disc-winged bats, use pads tipping their limbs to create suction and cling to furled leaves.

And until now, scientists had thought M. aurita also used its teensy pads for suction. Turns out, while the disc-winged bats have suction pads whose shape allows the animal to securely roost head-up, that's not the case for M. aurita.

These results, detailed in the Biological Journal of the Linnean Society, show M. aurita can still get a powerful hold.

"Each forelimb pad, on average, can hold roughly 8.6 times their own body weight," study researcher Daniel Riskin of Brown University in R.I. told LiveScience. "The equivalent would be a 150-pound rock-climber holding on with one hand and supporting their own weight, plus a 1,140-pound horse tied to their legs." ...

via Sticky Science: Why Some Bats Sleep Head-Up - Yahoo! News.