Calhoun's mouse experiments:

Transcript: Calhoun's mouse experiments

Calhoun:

The last thousand animals born never learned to develop the social behaviors. They never learned to be aggressive, which is necessary in defense of home sites. They never learned to court; there was no mating. Being no mating, there were no progeny and the older animals, whose behavior is already becoming disrupted, they eventually reach to, an age too old to reproduce. And so it was all left up to these last thousand or so, who we call the beautiful ones, because, not engaging in any stressful activity and only paying attention to themselves, they groomed themselves well so they look uh, very fine specimen. But from that point on, which was about the time that you were here two and a half years ago, this reproduction totally ceased and the animals have just aged and died.

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Calhoun:

Real mice, that is mice who are in the social sphere. All the others have been rejected in one way or another.

Interviewer:

What’s happened…

Calhoun:

…reproductive behavior's completely inhibited. It's inhibited because the last few hundred maintained them as juveniles and although they are now adults uh they no longer engage in aggressive behavior or in reproductive behavior. And we call them the beautiful ones because they are so excellent physically, they are unstressed. Now I see one down here. Most of these live in the apartment houses and rarely come out, but I see one who's taken temporary refuge in one of the nesting material supply cans. I’ll go over and pull him out, so that you can see what a beautiful specimen this animal is. 

Interviewer:

But as far as the mouse is concerned he’s a nothing?

Calhoun:

He’s a total nothing.

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Here he is lying in the can. It’s a place of temporary retreat. He’s colored very few, practically no wounds, he’s in excellent physical shape. He has two or three nicks but compared to most of the animals, he’s in excellent shape. And these animals from previous study shows that they are, are unstressed. They’re just not here insofar as involvement.

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Interviewer:

Have you noticed any changes in tissue?

Calhoun:

Well the major thing...

Interviewer:

The stress.

Calhoun:

The major thing, well certain classes of these for instance, comparing these males on the floor here who are withdrawn. They are highly stressed animals but the stress comes from each other because of the peculiar violence that they exhibit. Which leaves them as this animal, with his tail all chewed up, but they do it to each other. He's a highly stressed individual. On the other hand, the beautiful one which I just showed you, are very, extremely unstressed. Dr. Julius Axelrod has run the assay of the enzyme which converts noradrenaline to adrenaline as the basis for this. On the other hand, we’ve been removing females from other populations just terminated and looking at their uteri, and for animals up to a year of age who’ve come up in the latter history of the colonies there’s essentially no evidence of conceiving. So they’ve, at this stage, this is part of the over-living phenomenon. And it's these individuals who are not conceiving are the ones which are not stressed. They’re the beautiful ones who lack involvement.

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"'Socially active' for this simple species implies roles in the contention for, acquisition of, or maintenance of a territory. Some young males who enter the social milieu may succeed in replacing a territorial male. Other young males contend for a time before total rejection from the social flux of status striving. All such replaced dominants or rejected contestors became recruits in a socially pathological category of withdrawn males. No longer having access to the sheltered living spaces, these males aggregated in compact pools in exposed public space. The withdrawn males restricted their motor activity to the minimum required to obtain food and water. They exhibit a marked lowering of the threshold of tolerance to disturbance; very minor dislocations of their usual sedentary relations precipitate violent episodes of aggression that culminate in severe mutual wounding without any attempt to escape." 

"Both males and females fail to mature socially. Behaviorally, they continue into adult life as juveniles, without the capacity for either mating or aggression; their normal adult roles never emerge. Females move into adulthood with rare, if any, pregnancies. Males return to the nesting boxes where they associate with their nonreproducing sisters, with males like themselves, or with the few remaining reproducing females. We term these males the “Beautiful Ones” because they are physically perfect specimens, free of the wounds characteristic of behaviorally more adequate males, who moved out into the social scene."

"At the maximum attained density, about 18 times the optimum, all of the more recently born males are Beautiful Ones; no new contenders emerge. The socially active males senesce and die, as do the large aggregates of withdrawn males living in public space. A few of the older, aggressive, male-like females exhibit territorial defense, but the bulk of surviving adults have lost their potentiality for engaging in the normal reproductive and aggressive roles."

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Matthew Alexandar Sarraf and Michael A. Woodley:

>It is also interesting to note that Calhoun (1973) observed that the decline of the mouse utopia colonies was accompanied by an increase in the prevalence of behaviorally abnormal mice—termed “beautiful ones.” Calhoun described these mice as “autistic-like creatures” (Calhoun, 1973, p. 86)<