The behaviour of a colony of eight laboratory cats and their reactions to a familiar and unfamiliar person were recorded and analysed. Seven of the cats were Domestic Shorthairs and one was a Persian. All were male and only one was intact.Maintenance behaviours (resting, sitting, drinking, eating, defaecating and urinating) were the most commonly observed behaviours (36% of observations). Comfort (grooming, scratching, sneezing, coughing, head shaking, stretching and yawning) and locomotory behaviours (walking, running, jumping from floor to shelf and shelf to floor) were also commonly observed (30% and 24.5%, respectively). Agonistic behaviours were rarely observed (1%). Other behaviours recorded included marking and investigatory (clawing, scratching post, rubbing cage, anal sniff, body sniff, wall/floor licking; 4%), play (2%) and vocalisation behaviours (2%).Walking, jumping, eating, drinking, scratching, rubbing, defaecating and urinating were observed most often between 08:00 h and 09:00 h. Running, walking, resting and sitting occurred most often on the shelves in the cage.The cats made more direct contacts with the unfamiliar person than with the familiar person. Significantly (P<0.01) more attention behaviours (rubs against person, claws person, stands and watches, jumps to floor, stretches head out to person, lies on floor near person) were observed on the first day of the human-cat study than on the second and third days for both the familiar and unfamiliar person.