There may be no more iconic reminder of a bat than the cute image of one hanging upside-down, wrapped in its wings like some couture leather cape. But not all bats sleep feet-up, dangling from trees or cave ceilings.
In the furled leaves of the so-called traveler’s palm in Madagascar, two species of wee little bats roost right-side up. Myzopoda aurita and M. schliemanni are just the size of a human thumb with a tiny wingspan of a mere six inches; they rely on sticky feet to adhere to the slick surface of the plant.
"They have these little adhesive pads on their thumbs and ankles that they use to cling to leaves," said paleontologist Gregg Gunnell of Duke University in North Carolina. "They don't really hang upside down like most other bats — they hang upright with these pads," he added. "The leaves curl up, so they're hidden inside the leaf." Scientists previously thought that the pads used suction to keep the bats stuck to the slippery surfaces, but recent research has shown that the action is wet adhesion, like that used by tree frogs.
The Madagascar bats are the only bats known to employ this technology.
While rare now, a new fossil discovery reveals that this wasn’t always the case. Scientists working in Egypt have reported the discovery of fossilized remains of two earlier species of these bats - one from 37 million years ago and the other 30 million years ago.
The researchers say that the fossils indicate that the "sucker-footed" bats lived for millions of years on the African continent before being relegated to Madagascar.
Gunnell and the team analyzed the fossilized jawbones and teeth of the extinct bats and said that they were virtually identical to the jaws and teeth of the two remaining species in Madagascar.
"We've assumed for a long time that they were an ancient lineage based on DNA sequence studies that have placed them close to very old groups in the bat family tree," said researcher Nancy Simmons of the American Museum of Natural History in New York.
The discovery has helped to shed light on some of the mysteries of where bats come from. Previous genetic research had connected the "sucker-footed" bats to a large "super-family" of bats that today resides mostly in South America, the scientists said.
The fossils suggests that the ancestors of the South American bats originated in Africa, migrated to Australia, then Antarctica and into South America by way of a land bridge that linked the continents until 26 million years ago, they added.
"Now, we can unambiguously link them through Africa," Simmons said.
See one of the Madagascar bats in all of its clinging glory in the video below:
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