Tickle Relishing Rats: Current Research Show that Rats Enjoy a Good Tickle

Did you know that rats enjoy a good tickle? My saimese rat, Teddy would enjoy play-wrestling with my hand. I would flip him on his back and rubbed his belly. He would run away, as if I would chase him, and hop back for more. He was the first rat to do this so it was quite entertaining. Teddy enjoyed our play-wresting and research shows that rats enjoy ticking and actually laugh! Read more to learn about rats and there ability to laugh and play!

Teddy enjoyed our play-wresting and research shows that rats enjoy ticking and actually laugh! According to Jeffrey Burgdof and Jaak Pankseep in their article, Tickling induces reward in adolescent rats, rats emit ultrasonic vocalizations in response to social situations (2001). These vocalizations allow rats communicate to each other and cannot be heard by other species. Researchers are able to hear these vocalizations using an ultrasonic microphone. So far, research has shown that rat (baby rats) emit distress calls to signal a need for maternal care using ultrasonic vocalizations. Rats also communicate through ultrasonic vocalizations during sexual behavior, intermale agression, rough-and-tumble play, and manual tickling. Another article by Brian Knutson, Jeffrey Burgdof, and Jaak Panksepp, Anticipation of play elicits high-frequency ultrasonic vocalizations in young rats, suggest that rats make vocalizations when they are even anticipating play (1998).

In Burgdof and Pankseep's study, adolescent Long-Evans hooded rats were first separated into two groups, rats who received light touch("petting") and rats who were tickled ("vigorous whole-body playful simulation"), and ultrasonic vocalizations were measured in 50-kHz (Burgdorf and Panksepp, 2001). Result showed that rats who were tickled vocalized 352% more than those w

ho were lightly touched. They were laughing out loud ultrasonically, if you will. Researcher then had to determined if the rats would learn to approach the experimenter's hand to receive tickling. The results here showed that rats "received tickle stimulation ran about four times faster than the light touch control group across trial blocks." In other words, these rats would approach the experimenter's hand for tickles! To test this even further, rats were trained to press a button to receive tickles. Rats pressed significantly more on the button that resulted in tickles as compared to button without tickles. This shows that tickling reinforced interaction with the experimenter, suggesting that rats enjoy the tickling!

Why are researchers even looking into rat laughter and ticking? Jaak Panksepp in his article, Neuroevolutionary sources of laughter and social joy:Modeling primal human laughter in laboratory rats, states, "further study of this phenomenon may provide a theoretical as well as empirical handle on the sources of social joy within the mammalian brain." (2007). In other words, we can learn more about human joy through learning more about rat laughter. He also states,

We encourage others to become involved in this work. It may be of first-rate importance, if the basic play processes of the brain, along with the playful laughter sounds that accompany play, are ancient psychobehavioral tools that promote the epigenetic development of fully social brains in both rodents and men. Such findings may have useful cultural and biomedical impact.

I believe rat laughter is important to better understand human emotion and behavior. These studies can also provide "understanding clinical disorders such as attention deficit hyperactivity disorders (ADHD), addictive urges and mood imbalances" (Panksepp and Burgdorf, 2003).  I agree with Pankseep that such research can be beneficial to behavioral studies and medicine.

Next time you are playing with your ratties, have in mind that they may be laughing with you. They are also more complex in nature than previously though and are a big contribution to the scientific community and health sciences. We owe a lot to these lil' critters, so let's return the favor by giving them a lot of tickles!

Thanks for reading!

References:

Burgdorf J, Panksepp J. Tickling induces reward in adolescent rats. Physiol Behav 2001;72:167–73.
Burgdorf J, Panksepp J. Laughing rats and the evolutionary antecedents of human joy? Physiol Behav
2003;79: 533-547.
Panksepp J. Neuroevolutionary sources of laughter and social joy: Modeling primal human laughter in laboratory rats. Physiol Behav 2007; 182: 231-244.Knutson B, Burgdorf J, Panksepp J. Anticipation of play elicits high-frequency ultrasonic vocalizations in young rats. J Comp Psych 1998;112:65–73.