The yellow mongoose C. penicillata, a common small carnivore in southern Africa, was the subject for a social and feeding behavior study on an island in the Vaaldam, South Africa. Five actively used warrens occurred in the 20 ha study area. Old individuals sometimes live in single holes, but maintained contact with their original colonies. Temperature had a marked effect on the yellow mongoose activity patterns and the time of sunrise was therefore important. Some individuals were more active by night. As much as 90 min/day was spent sunbathing; different postures are illustrated. The hunting range of Cynictis coincided roughly with the territory which was 5-6 ha in extent. Although termites were the favorite food, the species is opportunistic and almost anything is taken, fruit being important in winter. A definite social heirarchy existed in every colony which consisted of a family group of a dominant male and female, their youngest offspring, 3-4 other young adults and usually also a very old individual. The dominant male and female defended a territory which the male demarcated daily.