Adaptation to living in an open arid environment: lessons from the burrow structure of the two southern African whistling rats, Parotomys brantsii and P-littledalei

This study examines interspecific differences in the architecture and field characteristics of the burrow systems of Brants' whistling rat, Parotomys brantsii, and Littledale's whistling rat, Parotomys littledalei. The two ro dents are endemic to the arid west region of southern Africa. Both build co mplex burrow systems with numerous nest chambers and associated interconnec ting tunnels, as well as a number of entrances. Burrow systems of P. little dalei are restricted to areas of good plant cover, whilst many P. brantsii burrows are situated in open locations with only limited plant cover. Furth er, the burrows of P, brantsii cover a much larger area than those of P. li ttledalei, with many more entrances. As P. brantsii feed predominantly with in the boundaries of their burrows and not in the open veld, their burrow s ystems effectively serve as a predator refuge, into which this diurnal rode nt can quickly run in the event of danger. Thus, by building large multi-ho led burrow systems, P. brantsii have become independent of the protection o ffered by bush cover and can exist within relatively open areas within thei r distributional range. On the other hand, the reduced number of entrances to P. littledalei burrow systems may largely restrict this species to areas with adequate cover, including coastal and riverine bush, with which it is often associated. (C) 2000 Academic Press.