NIPPLE-SEARCH PERFORMANCE BY RABBIT PUPS - CHANGES WITH AGE AND TIME OF DAY

Developmental changes in the nipple-search behavior of rabbit pups (O. cuniculus) were investigated from day 1-day 13. The performance of 4 litters was tested 1 h before and 6 h after the once-daily nursing and of 2 litters 6 h before and 1 h after nursing on lactating does restrained on their back. During the 1st 5 days, the median times taken by pups to attach to nipples decreased from 11.8-3.2 s. This improvement was mainly due to a decrease in the latency to search and suggested an improvement in the ability to react to the nipple-search pheromone. Except for the 1st day, pups located nipples faster before than after nursing and were best 1 h before. After the 1st wk, latencies to search remained minimal at this time, but increased again at the other times and were longest on day 13 at 1 h after nursing. Performance changes with time of day corresponded to daily changes in activity and, after the 1st week, suggested a further development of underlying motivational mechanisms.