The hypothesis that Brants' whistling rat Parotomys brantsii is a central place forager, whose foraging decisions are modified by (a) predation risk, (b) time of day, and (c) food choice, was tested. Field observations showed that whistling rats followed central place foraging rules for a single-prey loader and much of their food material was brought back to burrow entrances to feed on, with larger food items being carried back greater distances than small ones. Small food items were consumed in situ more often than large ones, suggesting that predation risk may also play a role in their foraging behaviour. Larger food items were preferentially stored at burrow entrances or carried underground, whilst smaller items tended to be consumed immediately. Individuals foraged more actively in the afternoon than in the morning and, although there was no tendency for individuals to eat more food at this time, far more food was stored or taken underground during the afternoon. Different foraging strategies were used for different plant species with some species preferentially eaten, and others stored or taken below ground more frequently. This study shows that the foraging behaviour of Brants' whistling rats is complex, and whilst they may follow simple central place foraging strategies, other factors such as the time of day and food plant species also influence their foraging behaviour.

The foraging behaviour of wild and captive colonies of the common mole-rat Cryptomys hottentotus hottentotus was investigated. Field studies were undertaken at Steinkopf, an arid site in the Northern Cape, South Africa. The resource biomass and the total available energy here were amongst the highest recorded for any bathyergids, but geophytes were sparse and widely distributed. The low probability of locating these widely dispersed resources should promote co-operative foraging in these mole-rats. All common geophyte species were consumed, probably because high burrowing costs favour dietary generalism. The mole-rat biomass per metre of burrow system (0.5–1.5 g.m-1) remains the lowest of any subterranean mammal. Burrow depths and diameters were positively correlated to the average mass of the mole-rats in each colony, apparently minimizing energetic costs and maximizing foraging success. Bulbs were stored in central food caches, and both field and laboratory data indicated size-based selectivity in their storage and consumption. As predicted by central place foraging theory, large bulbs were preferentially stored, and small bulbs preferentially consumed. However, factors other than energetic considerations may also influence these storage decisions. Total consumption time of bulbs was negatively correlated to animal size, and furthermore smaller bulbs were consumed more rapidly than larger ones. In addition to geophyte-storing, C. h. hottentotus also exhibited an alternative foraging strategy, termed ‘geophyte farming’, in which large bulbs were left and eaten in situ, and served as a renewable resource. Together with these foraging specializations, the evolution of sociality in mole-rats is a key factor which enables them to live in some of the most formidable habitats in Africa.