The men who tickle rats

Apparently, if you tickle a rat it will respond with vocalizations that scientists have good reason to interpret as happy ones. Basically, it's the rat equivalent of laughter, only at ultrasonic frequencies that the human ear can't detect on its own. What's more, tickling rats on a regular basis appears to reduce the negative effects of stress in their lives. Scicurious' write up of this research includes the amazing quote: "For the “tickling treatment”, rats were tickled once daily, in two sessions of two minutes each, for two weeks." Also, there is video of this.


    1. I, for one, definitely can’t think of any reason why work on an animal model for research on stress could possibly be justified.

      It’s not as though psych morbidity and mortality curb stomps practically everything that isn’t cancer, old age, or caused by high fructose inactivity, in terms of severity in the developed world…

    2. Me too :) I’d much rather investigate laughter, stress, and sensory responses in mammals with my tax dollars than pay for drone strikes.

  1. That is adorable, but is there *really* a question as to whether positive things change a stress response? Am I reading that wrong? Doesn’t removing stress typically change a stress response?

    1. Not always. In certain species of animal with more brainpower, stress responses can last long after the animal has been removed from the stressful situation. Humans are especially adept at driving themselves nuts, as we can use our brains to visualize stressful situations, and our bodies respond to them as if they’re actually happening right in front of us. I wouldn’t find it hard to believe that a rat can ruminate, too.

      1. Interesting. Too bad tickling doesn’t work that well on us. 

        (ok. maybe for some. to me it feels more like some kind of seizure) 

  2. At the end he said, “And when we tested these animals to see whether they enjoyed it, they said ‘Yes'”. Huh? Rats answering “Yes” would be more amazing than laughing when tickled!!


  3. Touch is such an essential part of animals’ well-being, including humans. Do only social animals enjoy being touched, or are there other organisms who don’t have complex social structures but like a good tickling now and then?

  4. as a rat owner, i can attest to this. tickling invokes playful conniptions in younger rats as they bounce around wildly, much like they would if play wrestling with other rats. it helps develop a stronger owner/pet bond than humans simply being that weird thing that keeps giving me more food.

    some rats also respond to gentle scratching with tongue licks in approval.

  5. As a neuroethologist and pet-rat owner myself, I’m not very sure about calling this a response to tickling. I’m inclined to think (only from personal experience, there’s no literature that I know of that supports this claim) that rats tend to see their care takers as bigger rats once they trust them. One infallible way to know that your rat, be it a test subject or pet, trusts you, is that he’ll let you put it on its back without trying to turn around. He may even lick your hands, as was mentioned in another comment. I think the stimulus, in this case, is the simulation of rough and tumble play, only that it takes place with a human’s hand instead of with a fellow rat.

    There’s other examples of work with ticklish rats, such as this one, from Mexico:
    I would’ve expected a better response to this post from boingboing readers! Remember, basic science is not about progress, but about generating knowledge. Rats are the most important animal model in science, specially neuroscience. These data are more about understanding our animal model than about your stressed out grandma, but it represents tax money put to good use nonetheless, because these data could help understand people eventually. Research does not have to be ground breaking to be valuable. That most people do not understand this is the reason why funding is so scarce. On the other hand, whoever tells you his own research is ground breaking and will save lives in the short term is very likely lying to you and his professional ethics should be put into question.

    1.  That’s a very interesting way to put it! I’ve never thought about animal research in that light, but it makes a lot of sense. There’s no use in testing the effects of something on rat behavior if you have no idea how the average rat behaves.

  6. Problem is that “stress” can be caused by anything out of the norm.  IE take a human and give them all the money in the world they want… and that creates stress too. The issue is how they respond to stressors.  If you set a rat up to have a major negative response to tickling once, you will probably not get laughing.  The way I see it if the stress invokes a negative response in a major way, you get PTSD…That’s why some people react to tickling by Stomping your face.  :).

  7. Everybody needs to take a breath and refer back to Garcia’s “Rat in the can” experiment!

    I’ve not read this new research, but I very much hope that the researchers reporting this are aware of Garcia. In short, you can lower stress levels of rats by making them think they are going to die many times a day for several days.  Their stress levels adjust and they become rat-neurotic, which looks to a human like a calm, stress free rat but is really a fried rat.  The way you make them think they are going to die is to have organisms several orders of magnitude larger than the rat pick them up and “tickle” them.  Or, in the case of Garcia’s original research, pet them and make nice cooing noises. 

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