A long-winged bat uses rising air currents to become a high flyer.
Nocturnal bats can reach air speeds of 135 kilometres per hour and altitudes of 1,600 metres above sea level — with assistance from pockets of rising night air.
Some bats soar hundreds of metres aloft in a few seconds. But flying fast and high can be challenging after dusk: winds are weaker than during the day, and landmarks that can aid navigation are invisible.
To explore how nocturnal bats achieve high-performance flight, Teague O’Mara at Southeastern Louisiana University in Hammond and his colleagues equipped European free-tailed bats (Tadarida teniotis) with miniature GPS trackers. The devices recorded the animals’ location every 30 seconds for 1 to 3 nights, during which the researchers collected local wind data.
Free-tailed bats flew mainly 100–300 metres above the ground. But occasionally, the nocturnal mammals rode rising air currents called updrafts, which form where winds meet the side of mountains or hills. The bats caught the updrafts to high altitudes where winds are light. Once aloft, the animals attained air speeds that are among the highest known for self-powered vertebrate flight.