The above diagrams exhibit the results of Adams, Shaw and Snode’s research. Some species of bats use their tails to assist in takeoff and flight. Courtesy of the UNC Chiropteran Research Laboratory
With the help of slow motion, highly sensitive cameras and wind tunnels, a UNC professor and two graduate students have made a new discovery involving the role the tail plays in the flight of bats.
Rick Adams, a professor of biology at the University of Northern Colorado, has studied bats for more than 20 years. It was only in the past few years, though, that he and his colleagues made a new discovery about the tail membranes in certain species of bats. Their research found the movement of the tail membrane creates a thrust during takeoff, unlike vertebrate in any other flying species.
"We're pretty diverse, so I would say one third of the research surrounds movement," Adams said.
Adams, along with former graduate students Jason Shaw and Emily Snode, who received their doctorate and master's degrees, respectively, last spring, took the high-speed videos, which revealed the tail movement indiscernible to the naked eye.
Adams said most video research done on bat movement is taken with a slow-motion video camera, and that 97 percent of the research on bats flying is conducted in wind tunnels. Wind tunnels create a false environment and not enough research has been completed to determine whether bats' natural flight differs from flight observed in wind tunnels.
It also does not account for takeoff movement, Adams said. He, Shaw and Snode wrote a peer-reviewed article on their findings in which they detail how they were able to observe a fairly natural takeoff. The article is available on the Public Library of Science website.
"We filmed 95 individuals of five species of vespertilionid bats as they launched from a horizontal platform after being held stationary by hand," Adams said.
The researchers first noticed the bats' tail movements when they were flying directly at the camera. Follow-up videos revealed the unexpected movement of the tail both above and below the body coordinate with the movement of the wings. The tail does not simply produce a thrust upon lifting into the air; it seems integral to the actual movement of flying.
Between taking and digitizing the video, Adams said it took a couple of years to prepare the research to present in a journal.
"People have been pretty amazed," Adams said.
Though it has not been available long, the article has more than 1,500 views, and Adams hopes for more publicity as well as follow-up research on how much force the tail can produce.
Adams has been a biology professor at UNC since 2002 and is the founder of the Colorado Bat Society, which exists "to foster public appreciation of bats and to support the conservation of bat populations in Colorado," according to their website.