Already a fairly unconventional flying animal, bats became even stranger as researchers detailed how extra weight on their wings allows them to land upside down.

Published in the journal PLOS Biology, the new study examined how bats differentiate further from birds and insects with extra mass on their wings. Conventionally, lighter wings would make for easier flight, but bats are already quite different from other animals capable of flight.

"Bats land in a unique way," study senior author Sharon Swartz, a biologist at Brown University, said in a press release. "They have to go from flying with their heads forward to executing an acrobatic maneuver that puts them head down and feet up. No other flying animal lands the same way as bats do."

For their study, the researchers recorded bats with high-speed cameras to then watch them perform their unique landing frame by frame.

"When they come in to land they're not moving very fast, which makes it hard to generate the aerodynamic forces needed to reorient themselves," study co-author Kenny Breuer, of Brown's School of Engineering, said in the release. "So the question is, how do bats get themselves in position to land?"

The researchers likened bats' ability to an Olympic diver that flips and twists while falling from a platform into the pool.

"What this tell us is that in bats, with their heavy wings, it's the inertial forces that are more important relative to aerodynamics," Breuer said. "That's a bit of a counterintuitive conclusion. Normally you'd think that an animal would not want to have such massive wings. But here, it turns out that the mass can be used to some benefit."