Bats are some of the only mammals on the planet with the ability to fly, and they are quite good at it. According to a report from Christian Science Monitor, scientists have been studying the ways in which bats are able to perform their complex dives and landings for some time now.

A recent study from Brown University reveals a shocking truth about the design of bats; they fly better when their wings are heavier. It was long believed that a lighter wing makes for a smoother flight, but recent research suggests that this may not be the whole case.

According to the study’s head author, Sharon M. Swartz, “We always tend to think of weight as a problem for anything that flies. Designers are always working on making things lighter.” Dr. Swartz’s research on two bat species, however, reveals that inertia is critically important for bats’ ability to fly.

By drawing their heavy wings in, bats can take advantage of their inertia to continue to propel themselves forward and perform mid-air stops and shifts while hunting. It also helps them grasp onto a landing zone in an upright position when it’s time for them to roost.

Bats inhabit heavily wooded areas and caves, so flying with tight maneuvers is essential. Since flight speed cannot be used to initiate complex maneuvers in many situations, bats need to rely on their heft to move at the last moment.

Bats are some of the only animals that capitalize on inertia to help them move about. Other common forces used in animal locomotion include ground reaction forces, hydrodynamic forces, and aerodynamic forces, all based on the principle of “pushing” against another substance, be it the ground, water, or air.

High-speed cameras captured two bat species, Sebea’s short-tailed bats and dog-faced fruit bats as they flew around in an enclosed space and perched upside down on a hangar attached to the ceiling.

The bats flipped upside down by pulling one of their wings closer to the body while the other remained extended. This is similar to the way figure skaters can control the speed of their rotation around a central axis by extending or retracing their arms. The bats were able to move in and out of this position with ease when researchers removed the landing pad on the ceiling.

Dr. Swartz hopes that the research could be used to inform new designs for drones and other flying robots that could even be used around the house. Scientists have long looked to nature for inspiration for new designs, and the way bats fly could have profound implications for flight technologies in the coming years.

A press release from Brown University outlining the details of the study can be found here.