The nocturnal behavior of a pair (1,1) of brown hyenas (H. brunnea) was studied for 3 mo. in 1973. The pair of animals was kept in a 0.2 ha compound which was bordered by the compounds for Cape hunting dogs, striped hyenas, and the African steep section of a safari park in southwestern Oregon (USA). Observations were made with the use of a starlight scope, a light amplifying instrument. The brown hyena is a strictly nocturnal animal, becoming active shortly before sunset and continuing its activities until the early morning hours. The 3 wk breeding period in which the duration of the activity period was extended by half was discussed. Comparisons of various behavioral patterns of the brown hyena are made with those of the better documented spotted hyena to set a basis for future studies of the species.