Structure and function of the eastern grey kangaroo (Macropus giganteus) foot thump

Abstract

Most species of the family Macropodidae (kangaroos and wallabies) make a distinctive foot thump by striking the ground with their hind feet when they detect potential danger. I used the eastern grey kangaroo Macropus giganteus as a model to examine (1) the acoustic characteristics and structure of the thump, (2) the social context in which free-ranging kangaroos thumped when approached by a human observer on foot and (3) the intended recipient of the signal. Thumps were about two-thirds of a second in length, generally composed of two noisy pulses, and had the majority of the signal energy below 7 kHz. Only adult kangaroos, of both sexes, were observed to thump. A higher proportion of solita..