In order to reproduce, mammals have to find and recognize an appropriate mate (belonging to the same species, opposite sex, adult, in breeding mood, sexually appealing). Monogamous mammals undergo this search once in life; solitary mammals have to seek mates each year. Subterranean mammals do not differ in this respect from their surfacedwelling counterparts. In 1987, two research teams reported, simultaneously and independently, the discovery of a new, previously unconsidered, mode of communication in blind molerats: vibrational (seismic) signaling.
The animals can put themselves into efficient contact through vibrational signals produced by head drumming upon the ceiling of the tunnel. Communicative drumming by hind feet was reported for solitary African mole-rats (Georychus and Bathyergus). This behavior, however, could not be found in another solitary African mole-rat, the silvery mole-rat (Heliophobius). It can be speculated that seismic signaling evolved in those solitary species that disperse and look for potential mates underground. Subterranean mammals that usually occur at lower population densities and whose burrow systems are far apart from each other have to cover larger distances (which would be impossible to do by digging) in order to find a partner. They dare to carry out their courting above ground. These mammals such as the silvery mole-rat, the naked mole-rat, or the European mole have not invented seismic communication. Moles wandering at the surface in hopes of finding a burrow of a female probably are led by olfactory signals.