A technique that is increasingly used worldwide to improve the welfare of rats in research is rat “tickling”—whereby humans make light, brisk, and vigorous movements with their fingertips on a rat’s neck and abdomen to imitate juvenile rat rough-and-tumble play. Rat tickling is generally seen to be a positive experience for rats; for example, many “laugh” (i.e., vocalize in the 50-kHz range indicative of positive emotional state) when tickled and afterwards spend more time in locations where they were tickled and show reduced fear and anxiety to various stressors.
However, not all rats respond in the same way. The current technique relies heavily on pinning rats on their back to tickle their abdomen, because that is when they laugh the most—although some rats do not laugh at all.
AWI wholeheartedly supports techniques to better the welfare of rodents used in research. We also support efforts to make such techniques even better for animals. In a recent opinion article published in the open access journal Frontiers in Veterinary Science (Bombail et al., 2021), a group of scientists proposed that tickling may not be a positive experience for all rats and that current tickling methods could be improved.
During social play, rats occasionally choose to roll onto their backs to be pinned by their play companion; during tickling, pinning is not only used much more often than during social play, but is also forced on the rat by flipping them onto their back. In order to make tickling more responsive to different rat personalities, the scientists suggest incorporating more aspects of rat play (such as chasing, sparring, and wrestling), reducing the amount of pinning, and paying attention to individual rats’ responses during each session. The authors believe that the result “would be a more inclusive tickling method that is … likely to be a pleasant experience for more rats, including individuals [who] do not enjoy being pinned.”