BEHAVIOR OF RATS IN THEIR HOME CAGES - DAYTIME VARIATIONS AND EFFECTSOF ROUTINE HUSBANDRY PROCEDURES ANALYZED BY TIME SAMPLING TECHNIQUES

The behaviour of laboratory rats in their home cages was observed on b oth the mornings and the afternoons of days when cages were cleaned an d compared to days when cages were not cleaned. Two different time sam pling methods, 'instantaneous sampling' and 'one/zero sampling', were used and compared. In general the rats were more active in the morning s than in the afternoons. Activity, particularly locomotion and that a ssociated with manipulation of the bedding was increased during both t he mornings and the afternoons of cleaning days. Defaecation also incr eased on cleaning days whereas sitting decreased. The cleaning regime appeared to have a greater effect on behaviour than did time of day an d the effect of cleaning lasted for several hours after the procedure had been completed. The implications for experimental design are discu ssed.