Fastest bat

The fastest-flying bat, and the fastest-flying mammal overall, is the Brazilian free-tailed bat (Tadarida brasiliensis), native to southern USA, Mexico, Central America and most of South America, with maximum ground speeds of 44.5 metres per second (145 feet per second; 160.2 kilometres per hour; 99.5 miles per hour). The measurements were recorded in July 2009 in the vicinity of the Frio Bat Cave, near the town of Concan, Texas, USA, and the results were published in the journal Royal Society Open Science on 9 November 2016.

Seven specimens fitted with radio transmitters were measured for this study, with flight data gathered from the air by plane. The overall median ground speed for the seven bats was 5.7 m s-1 (18.7 ft s-1; 20.5 km/h; 12.7 mph), but all logged brief bursts in excess of 25 m s-1 (82 ft s-1 ; 89.9 km/h; 55.9 mph); five of the seven achieved speeds greater than 30 m s-1 (98.4 ft s-1 ; 108 km/h; 67.1 mph).

The upper speeds logged in this research would also exceed those measured for the fastest birds in level flight. However, owing to the fact that fluctuating wind gusts and the effects of gravity (e.g., diving) could have impacted the results, some scientists have advised treating the data with caution and for further study to be conducted before it can be asserted that these bats are the fastest animals in horizontal flight overall. There are several other contenders for this title – all birds – including the common swift (Apus apus), the white-throated needletail (Hirundapus caudacutus) and the grey-headed albatross (Thalassarche chrysostoma), all of which are debated depending on the conditions in which they were flying and the accuracy of the measurement methods used.

The study was a collaboration between the University of Tennessee, Boston University and Brown University (all USA) and the University of Konstanz (Germany), led by Professor Gary McCracken of the University of Tennessee.