An example of burrow system architecture of dispersing Damaraland mole-rats

Abstract

The Damaraland mole-rat (Fukomys damarensis) is a social, subterranean rodent that occurs in the red Kalahari sands. This species exhibits extreme reproductive skew with a single breeding female whereas reproduction in subordinate group members is completely blocked. Rainfall, as it greatly facilitates burrowing, provides the opportunity for individuals to disperse from their natal colony and hence, to overcome reproductive suppression. However, because rainfall is scarce, optimal conditions for burrow system construction are restricted to very short periods of the year. In order to observe the construction of a new burrow system of dispersing individuals, I released a small group (two females, one male) following heavy rains, and monitored their burrowing activity in the form of mound production during the following weeks. Recapture revealed that a new male had joined the group. Over a period of one month the four individuals extruded 127 mole hills and constructed a tunnel system with a total length of approximately 100 metres. Mound production ceased after 30 days due to the lack of subsequent rain. The study provides an example of dispersal in Damaraland mole-rats and gives new insights into the method of burrow system construction of this species. It further highlights the high costs associated with dispersal.

Keywords: Bathyergidae, dispersal, Damaraland mole-rat, burrow system, reproductive suppression.