'Silent squirrel screams' and mouse giggles

[Ivan Seeking]

Ground squirrels make an alarm call so high pitched that we cannot even hear it, scientists report in Nature. [continued]

http://news.bbc.co.uk/2/hi/science/nature/3932943.stm

About eight or nine years ago I had a newspaper clipping about the discovery by a biologist that when tickled, mice produce ultrasonic giggles. I will try to find the story but I know for a fact that it was reported in the Portland newspaper. If someone spots this story before I get back please post.

[Moonbear]

This isn't that surprising, the only thing that is surprising is it got published in Nature! It's commonly known that rodents emit ultrasonic vocalizations. They've been recorded during mating and when introducing an intruder...for both rats and mice. I'm not surprised it can be generalized to other rodent species. I'm not so sure about the tickling thing. It might have been an alarm call too. I'm sure the mouse perceives being "tickled" by a human differently than the human performing such an action.

[Ivan Seeking]

Well I just did a bit of a search and nothing popped up. What this scientist found while using a ultrasonic bat detectors for something else entirely was that when he played with the mice - doing things like quickly and lightly rubbing their bellies, which they like - the mice could be heard producing short bursts of ultrasonic chirps. They did sound like giggles but I don't know the proper interpretation for these sounds.

[Moonbear]

Is this what you're thinking of? It's late, so I haven't read it, but the abstract sounds like they include that paper you're talking about as an example in this review.

If you go to PubMed, just use ultrasonic vocalizations as your search term and lots of citations will show up (that's how I found this one).

Physiol Behav. 2003 Aug;79(3):533-47.
*
"Laughing" rats and the evolutionary antecedents of human joy?

Panksepp J, Burgdorf J.

Department of Psychology, J.P. Scott Center for Neuroscience, Mind and Behavior, Bowling Green State University, Bowling Green, OH 43403, USA.

Paul MacLean's concept of epistemics-the neuroscientific study of subjective experience-requires animal brain research that can be related to predictions concerning the internal experiences of humans. Especially robust relationships come from studies of the emotional/affective processes that arise from subcortical brain systems shared by all mammals. Recent affective neuroscience research has yielded the discovery of play- and tickle-induced ultrasonic vocalization patterns ( approximately 50-kHz chirps) in rats may have more than a passing resemblance to primitive human laughter. In this paper, we summarize a dozen reasons for the working hypothesis that such rat vocalizations reflect a type of positive affect that may have evolutionary relations to the joyfulness of human childhood laughter commonly accompanying social play. The neurobiological nature of human laughter is discussed, and the relevance of such ludic processes for understanding clinical disorders such as attention deficit hyperactivity disorders (ADHD), addictive urges and mood imbalances are discussed.

Publication Types:
• Review
• Review, Tutorial

PMID: 12954448 [PubMed - indexed for MEDLINE]

[Ivan Seeking]

WOW! Yes I'd say that's the one. May or may not be the say scientist but definitely related work according to what I remember. IIRC, the scientist that I saw and read about was suggesting that the sounds were laughter, but this many years down the road I can't be sure if he was serious or joking. I know I first saw this at least eight years ago.

[Moonbear]

Apparently, the chirps sound a bit like laughter. It may have been the scientist's attempt to explain the concept in non-technical terms for a broader audience. I haven't looked any further yet, but it certainly seems that if we can interpret an animal's expression of happiness, or comfort, or even discomfort, that would go a long way toward improving animal welfare.

[Ivan Seeking]

An update about this from the GD forum.

http://www.physicsforums.com/showthread.php?t=69429

[DocToxyn]

Here's a lighter version (http://www.livescience.com/animalworld/050331_laughter_ancient.html) of Panskepp's work, pretty interesting stuff and I remember reading about the rat study several years ago as well. My pet rats always seemed to "enjoy" a good tickle :smile: and frequent handling/playing always made for a better pet. Whether they were laughing... I don't know, but they usually made me laugh.

[Moonbear]

Here's a lighter version (http://www.livescience.com/animalworld/050331_laughter_ancient.html) of Panskepp's work, pretty interesting stuff and I remember reading about the rat study several years ago as well. My pet rats always seemed to "enjoy" a good tickle :smile: and frequent handling/playing always made for a better pet. Whether they were laughing... I don't know, but they usually made me laugh.

From that article:
"Young children, whose semantic sense of humor is marginal, laugh and shriek abundantly in the midst of their other rough-and-tumble activities," Panksepp notes.

It always sounds far more like shrieking than laughing to me in small children. :biggrin: When I hear a small child shriek, I usually have to ask their parent(s) whether it's a "good" shriek or a "bad" shriek. It seems the interpretation of the same sound is pretty context dependent, and if I can't see the context (i.e., my nephew is shrieking in the background while I'm on the phone with my sister), I really can't tell what the sound means. Why am I sharing this? Because it leaves me wondering that if I can't really tell in a small human what a particular sound means without noting the context, it seems there's quite a big risk of anthropomorphism in interpreting these animal sounds when we aren't particularly good at interpreting what the sound OR the context is.

Though, I do have one of Jak Panskepp's books, which I haven't had a chance to read yet, because I am interested in how he is interpreting the neurobiology of emotions. This is an interesting topic, and a challenging one to study. I just think caution is really important to ensure we don't head down a misleading path due to misinterpretation of what identifiable behaviors mean.

[DocToxyn]

it seems there's quite a big risk of anthropomorphism in interpreting these animal sounds when we aren't particularly good at interpreting what the sound OR the context is.

I completely agree, and coming from a background in animal behavior, I was indoctrinated with the anathema of "humanizing" the animal. Now I don't always follow this dogma (outside the lab), but in these experiments, at least the lab-based ones, I think the context is can be fairly well controlled. Engage the rat in play, record vocalizations, compare to vocalizations from other activities - eating, exploring, fighting, etc. Try to isolate differences and then possibly look for other occurences of said "happy sounds", perhaps during mating. To step it further and call it laughter may be going too far, but perhaps he is only trying to make it more familiar to us, rather than calling it something like play-stimulated repetative vocal eruptions.