Territorial behaviour of a clan of spotted hyaenas, Crocuta crocuta, was investigated in the Kruger National Park over a period of 27 months. These hyaenas were highly territorial, spending ⅕ of their total activities on territory patrol by scent-marking intensively and monitoring 64 marking posts, particularly in border regions. Females, the more philopatric sex, were most active in territory defence. Local intensity of territorial activities by residents within their 130-km2 territory was directly proportional to intrusion pressure by neighbours. When clan size was reduced, the ability to defend disputed land declined and larger neighbouring clans appropriated parts of the territory. We propose a relationship between resource distribution, intrusion pressure and territory defence.