Abstract: | This paper describes some behaviour patterns of the guinea-pig, Cavia porcellus, which vary systematically with the oestrous cycle. Oestrus is characterised by an increase in locomotion, and scent-marking, as well as by greater interest in conspecifics. All of these are behaviours known to increase at oestrus in other rodent species. The significance of these changes for the social organisation of this species is discussed. |