The mongoose family (Herpestidae) has provided a wealth of data on life history patterns and behavior of its more social species but little is known about the many solitary mongoose species. Here, we provide the 1st longterm data on life history patterns and the biology of the solitary slender mongoose (Galerella sanguinea) in the Kalahari Desert, South Africa. Slender mongooses are strictly diurnal, solitary foragers, opportunistically hunting vertebrates and invertebrates. Life history patterns, such as a prolonged period of offspring dependence, including age at 1st emergence, at 1st foraging, and at weaning, compared to social meerkats (Suricata suricatta), seem to be an adaptation to their mainly solitary life style.