THE USE OF SEISMIC SIGNALS BY FOSSORIAL SOUTHERN AFRICAN MAMMALS - A NEUROETHOLOGICAL GOLD MINE

Behavioral adaptations exhibited by two African fossorial mammals for the reception of vibrational signals are discussed, The Namib Desert g olden mole (Eremitalpa granti namibensis) is a functionally blind, noc turnal insectivore in the family Chrysochloridae that surface forages nightly in the Namib desert, Both geophone and microphone recordings i n the substrate suggest that the golden mole is able to detect termite colonies and other prey items solely using seismic cues. This animal exhibits a hypertrophied malleus, an adaptation favoring detection of low-frequency signals, In a field study of the Cape mole-rat (Georychu s capensis), a subterranean rodent in the family Bathyergidae, both se ismic and auditory signals were tested for their propagation character istics. This solitary animal is entirely fossorial and apparently comm unicates with its conspecifics by drumming its hind legs on the burrow floor, Auditory signals attenuate rapidly in the substrate, whereas v ibratory signals generated in one burrow are easily detectable in neig hboring burrows, The sensitivity to substrate vibrations in two orders of burrowing mammals suggests that this sense is likely to be widespr ead within this taxon and may serve as a neuroethological model for un derstanding the evolution of vibrational communication. Neuroethologic al implications of these findings are discussed. (C) 1997 Elsevier Sci ence Inc.