Tickling Rats For Improved Captive Welfare

Rats are becoming an ever-increasingly popular choice as companion animals in the U.S. Accordingly, the handling, welfare, and perception of these companion rats have all become topics of study for researchers. More specifically, researchers look to study the rats in “pet stores” (as referred to by the authors of the study) since they are usually expected to be more people-friendly.

This new study worked with pet store rats to determine if tickling them could help make them more approachable and positively-perceived. In turn, it’s expected that this would lead to better treatment and welfare for these companion animals.

Why tickle rats? The action is actually similar to how young rats rough house with each other, and the hand-to-rat contact helps the animal get used to handling. Previous research has demonstrated that tickling positively impacts rats’ behaviors, makes them easier for humans to handle, and decreases their anxieties. These responses are measured through the rats’ vocalizations, approach and handling tests, cage behaviors, and fecal tests for the presence of corticosterone, a hormone released in times of (good or bad) stress.

This study used all four of these methods to study 36 female companion rats (12 of which were studied for control variables), with the authors hypothesizing that tickling the rats would improve their welfare and lead to better interactions with humans. Further, the rats that expressed more vocalizations (the “high-callers”) were predicted to experience more benefits than those that vocalized less (the “low-callers”).

For seven days, the rats lived in a pet store and received daily tickle sessions from researchers and trained store employees. The rats were not to be sold during the experiment but were still on display for the public to see and interact with from outside the cage. On the third day, the rats were split into groups based on whether they were classified as low-callers or high-callers during tickling. The rats’ cages were continuously recorded during the latter half of the experiment so the researchers could watch cage behaviors.

Researchers tested the rats’ responses to human approach and handling on the eighth day in three steps, one rat at a time: first, a researcher (who was new and unfamiliar to the rats) placed her hand at the opposite end of the cage and waited one minute (approach). Then, she picked up and held the rat for 30 seconds, restraining movement (handling). Finally, she placed the rat back down and put her hand back to its original position at the opposite end of the cage (approach). During the process, the rats were observed for vocalizations, interest in the hand, and resistance to being picked up.

At the end of the study, the researchers’ hypothesis was partially supported. For one, customers did identify the high-caller rats as being happier, but they weren’t more likely to purchase these rats as companions (as opposed to being “feeder” animals for carnivorous companion animals). By the eighth day, the tickled rats were easier to pick up, even for handlers unfamiliar to the rats. The high-callers were less anxious during approach tests compared to the controls, but they struggled against restrained holds as much as the control rats did. Otherwise, the high-callers didn’t act very differently from the controls.

Rats that were tickled spent less time hiding away in their cages’ huts than the controls did, indicating that they weren’t as scared of humans. Interestingly, all of the rats had increased levels of corticosterone in their feces, which was an unexpected result but might be related to anticipating contact with humans. Since corticosterone is released in both times of pleasure and displeasure, it’s difficult to say whether this anticipation was out of excitement or fear.

Overall, this study had a few unexpected and mixed results, but it still has plenty of value: it shows us that, at the very least, touching these animals in a playful way may help humans view them in a more positive light when the rats are more active, appear happier, and are easier to handle. In turn, this could contribute to companion rats being treated better and living more fulfilling lives.

In the world of scholarly research, this study could be improved and replicated to get more robust and accurate data – especially as the popularity of companion rats continues to rise. The species is frequently perceived as being vermin and generally undesirable, so this kind of information can help turn the tide in the favor of rats and their human companions. Increasing empathy towards rats could also help to increase rates of rescue and adoption, rather than pet store purchases.