Tickling rats for improved welfare

Megan LaFollette and colleagues from Purdue University describe how tickling can benefit you and your rats. This piece was originally published in the August 2019 edition of Tech3Rs, our regular newsletter for animal technicians.

Tickling rats isn’t just for fun – it also makes handling easier and improves rat welfare. If you wish there were a better, faster way to handle rats that didn't induce fear or require restraint devices, tickling can help. In this article, we explore the benefits of rat tickling and give you tips for when and how to use this unique technique.

Rat tickling is a positive handling technique that was developed by a team of neuroscientists studying positive emotions and ultrasonic vocalisations in rats. They noticed that when rats are young, they play by running around and wrestling, similar to dogs. Like playing with dogs, so too can we play with rats.

“Rat tickling is a positive experience for the animal and the person. It creates a bond between them and reduces fear”, says Dr Sylvie Cloutier, who worked with the developer of rat tickling, Dr Jaak Panksepp, at Washington State University. Dr Cloutier conducted research showing that tickling rats before injections reduces fearfulness and increases behaviours associated with positive welfare. Tickling can also speed up restraint procedures, and is particularly beneficial for rats who are singly-housed so can’t play or socialise with other rats.

But I hate being tickled; shouldn't rats hate it too? This is a common concern, and it is true that some rats enjoy it more than others. However, rat tickling is not equivalent to human tickling, especially in adults – instead, it mimics aspects of wrestling and play behaviour. To avoid confusion, some researchers call it "heterospecific rough-and-tumble play" or "playful handling" rather than "tickling".

Rat play has two parts that we try to mimic during tickling. In natural rat play, one rat jumps on the back of the neck of another, who flips over in order to pin its playmate. When you are tickling your rat, make light, quick movements on the back of the neck for 2-4 seconds, then pick the rat up for the flip. Megan LaFollette, graduate researcher at Purdue University, recommends placing your index finger in front of the rat’s collar bone and your thumb and middle finger under its "armpits". Then "give a flick of the wrist" – once the rat is on its back, “tickle” its belly for 3-4 seconds. Repeat three times for 15 seconds per rat. After this, you’re done for the day, but ensure you repeat this process for at least the next two days before starting any procedures.

Some people worry that tickling will take a lot of time, is too rough, or will negatively affect experimental outcomes. In fact, tickling can be quick, purposefully mimics rough-and-tumble play, and generally improves research models by reducing anxiety. Explaining to others how this technique can replace traditional habituation procedures (and sometimes using the term “heterospecific play”) can help get others on board, as more and more researchers and laboratory technicians are doing. By tickling your rats, you can play an important role in improving rat welfare and scientific research.

Top tips for rat tickling

Play like a rat. Remember that tickling mimics rat rough-and-tumble play. Use online training materials and consult with or request supervision by colleagues with experience of the technique. Use one hand to make quick, light, but assertive contacts with the rat right over the shoulder area. Make sure not to tickle the rump of the rat, as this is where aggression is directed. Carol Dowell, Training Coordinator at Purdue University, recommends picking the rat up to flip their legs forward instead of turning the rat sideways. It may take you a little while to get the hang of the technique – always ask if you're not sure.

Tickle first, manipulate later. Tickle rats for three days before any procedures commence. On the day of procedures, tickle them before rather than after, when they may not be in the mood to play. Carol says, “if there’s a study for which they’re getting in younger rats, I recommend incorporating tickling into acclimating the rats and getting to know them. If you do tickling then, it makes the rats excited to see the glove.”

Tickle often, not long. The minimum recommended tickling period is 15 seconds for three days. Research shows there is no difference between rats tickled for 15, 30 or 60 seconds, so even brief sessions are still effective. According to Carol, once rats have been tickled for a few days, “even if you don’t tickle them for two to three weeks and come back to it, they still enjoy it.”

Read your rat. Try tickling rats for three days before deciding it’s not for them. Some rats just don’t like tickling as much, so make sure to read your rat. Use a bat detector or ultrasonic microphone to listen for positive or negative calls. Positive calls occur at 35-75kHz, while negative calls occur around 22kHz. You can also use the behaviour of the animal as an indicator. According to Dr Cloutier, positive indicators include “following the hand, licking the handler’s fingers, and not hiding or trying to avoid the hand.”

Consider your rat and the research model. Tickling is not best for every rat. Experts generally recommend not tickling breeder males or extremely stressed rats. Dr Cloutier warns that technicians should talk first to the researchers to make sure it’s OK to include tickling, particularly if the research requires animals to experience anxiety or fearfulness. However, in general, tickling will improve research validity by reducing rats' stress levels.

References

Cloutier S, LaFollette MR, Gaskill BN et al. (2018). Tickling, a technique for inducing positive affect when handling rats. Journal of Visual Experiments 135: e57190. doi:10.3791/57190

LaFollette MR, O’Haire ME, Cloutier S et al. (2017). Rat tickling: a systematic review of applications, outcomes, and moderators. PLOS ONE 12(4): e0175320. doi:10.1371/journal.pone.0175320