Bats use tiny hairs on their wings to guide their elaborate flights, according to a new study. The highly-agile fliers are capable of carrying out precise maneuvers due to the hairs, which are capable of detecting tiny changes in airflow taking place over their wings.
Nerve signals generated by the movement of air over the tiny hairs is sent to the brain of the flying mammal. This input allows the bat to make split-second decisions in directing flight path and attitude, resulting in precise flight maneuvers.
"Until now no one had investigated the sensors on the bat's wing, which allow it to serve as more than a propeller, a flipper, an airplane wing or any simple airfoil. These findings can inform more broadly how organisms use touch to guide movement," said Cynthia F. Moss, a neuroscientist with Johns Hopkins University.
Big brown bats, a species common around the United States, were examined during this new study. These creatures use their wings not just for flight, but also to capture insects, climb along surfaces and cradle their young. While bats also have echolocation, or reflected sound, to help guide their flight, they use the touch sensors to make wing adjustments to stabilize, slow down, and speed up.
Researchers discovered a vast number of touch sensors spread over the wings of the bats being examined and noted that many were located at the base of fine hairs. When these sensors were stimulated by puffs of air, the action lit up signals in the primary somatosensory cortex of the bat's brain. This suggests that sensors on the wings act as data relay centers, continually updating the flying mammal on air conditions.
The population and distribution of nerves over the limbs, known as innervation, was found to be unique in bats. In addition to connections between appendages and higher nerves of the spinal column similar to those seen in other animals, signals in bats also connect to lower regions typically utilized by nerves in the torso.
When researchers temporarily removed hair on the wings using a cream, the animals were not able to stop their flight as quickly as normal, and turns became wider.
Bats are the only mammal capable of true powered flight. The animals are capable of flying at speeds between seven and 20 miles per hour. They are also able to change directions quickly during flight and adapt to changing conditions in just a tiny fraction of a second.
"These findings lay the groundwork for understanding how bats use sensory information to fly with precision in the dark and catch prey midair. The information, researchers say, could eventually help people design air vehicles that better negotiate obstacles by sensing and adjusting to air turbulence," Johns Hopkins University researchers stated in a university press release.
Study of nerve cells on bat wings and their effect on the flight of bats was published in the journal Cell Reports.
Photo: Angell Williams | Flickr
