PT - JOURNAL ARTICLE AU - Matherne, Marguerite E. AU - Cockerill, Kasey AU - Zhou, Yiyang AU - Bellamkonda, Mihir AU - Hu, David L. TI - Mammals repel mosquitoes with their tails AID - 10.1242/jeb.178905 DP - 2018 Oct 15 TA - The Journal of Experimental Biology PG - jeb178905 VI - 221 IP - 20 4099 - http://jeb.biologists.org/content/221/20/jeb178905.short 4100 - http://jeb.biologists.org/content/221/20/jeb178905.full SO - J. Exp. Biol.2018 Oct 15; 221 AB - The swinging of a mammal's tail has long been thought to deter biting insects, which, in cows, can drain up to 0.3 liters of blood per day. How effective is a mammal's tail at repelling insects? In this combined experimental and theoretical study, we filmed horses, zebras, elephants, giraffes and dogs swinging their tails. The tail swings at triple the frequency of a gravity-driven pendulum, and requires 27 times more power input. Tails can also be used like a whip to directly strike at insects. This whip-like effect requires substantial torques from the base of the tail on the order of 101–102 N m, comparable to the torque of a sedan, but still within the physical limits of the mammal. Based on our findings, we designed and built a mammal tail simulator to simulate the swinging of the tail. The simulator generates mild breezes of 1 m s–1, comparable to a mosquito's flight speed, and sufficient to deter up to 50% of mosquitoes from landing. This study may help us determine new mosquito-repelling strategies that do not depend on chemicals.