- [Narrator] In a unique experiment that took years
to complete, Dr. Calhoun used white mice to study
population growth and its effects on individual behavior.
- The following is about a mice utopia
that became a rodent hell hole.
- Complete with cannibalism in a race of mice known as
The Beautiful Ones.
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- [Woman] In 1962, John B. Calhoun laid out the specifics
of his mice utopia-dystopia experiment
in a paper called Population Density and Social Pathology.
- [Man] But Calhoun's obsession with the question
of overpopulation leading to extinction didn't stop there.
In 1972 he devised his 25th iteration of rodent housing
with Universe 25, a 101-square-inch tank,
or 2.5 meters
enclosed by walls 54-inches high
or 1.37 meters high.
- [Woman] Each of the 16 walls had a stairwell soldered
to it in the form of vertical mesh tunnels.
Horizontal corridors opened off each stairwell,
leading to nesting boxes, and there was an endless supply
of food and clean water, as well as material to nest with.
- [Man] Moreover, the universe was regularly cleaned,
and the temperature never deviated
from 68 degrees Fahrenheit.
It was a predator-free, all-you-can-eat buffet of life.
A true Utopia.
Well, except for the prison-like structure itself.
- [Woman] Out of this universe rose groups of mice
known as "The Beautiful Ones," mice who retreated
to their apartments to meticulously groom themselves
and gorge on food, while below them,
the masses were entangled in a clutch of violence.
- [Man] So where did it all go wrong?
- [Woman] After four breeding pairs settled in their
new digs, they began to reproduce.
Every 60 days, the population doubled,
and soon the utopia began to sour.
There was plenty of room, but mice crowded
into certain eating and sleeping compartments,
which led to overpopulation in these areas,
resulting in some serious, aggressive behavior.
- [Man] The violence escalated so much that soon
random acts of violence were perpetrated among
the rodent population, with the majority of mice
entering a kind of freak-out mode,
ceasing to engage in day-to-day activities, like mating.
- [Woman] And while some dealt with population pressure
by becoming antisocial and retreating to the corners,
like the Beautiful Ones, others engaged in pansexual
behavior with one another.
- [Man] Female mice withstood attacks and aggressive
mating behaviors, eventually abandoning their offspring.
Some of them were attacked by their mothers or cannibalized
by other mice, even though there was plenty of food
to go around.
- [Woman] In the 1970s, an era that was experiencing
unprecedented population growth, Calhoun's finding
seemed to support a doomsday scenario for humans.
Books like Population Bomb and movies like Soylent Green
all warned of an end to the human race
through overpopulation.
- [Man] And the rodents' descent into cannibalistic
madness seemed like a likely model.
- [Woman] Except that Calhoun's experiment and the human
model of life isn't exactly apples to apples.
For the most part, we humans have agency,
meaning that there isn't some organism larger than us
scooping us up and forcing us to live in an enclosed tank
from which there is no escape.
- [Man] And psychologist John Friedman presented
the argument that it's not necessarily overpopulation
that was the problem with Universe 25.
Instead, it was the increased level of social
interaction that drove the mice mad.
Not to mention the fact that the mice born into Universe 25
didn't form the kinds of social bonds they normally would.
- [Woman] The big bummer is that even when the population
began to decrease, the mice weren't able to return to normal
activities like mating.
They simply died off.
- [Man] So besides inspiring paranoia in humans
that we're all gonna turn into pansexual cannibals
when the population reaches a certain number,
a couple of positive results came out of the experiment.
- [Woman] First was the discovery that not all rodents
went berserk.
There were some who adapted, even thrived, among the chaos.
And Calhoun created 100 more versions of Universe 25
to draw out this trait, trying to create what he called
high-velocity mice, with the hope that he could apply
this rodent creativity to the human problems
of population density.
- [Man] The second was the beloved film,
The Secret of Nimh, which was originally a children's book
about super-intelligent rats escaping
the National Institute of Mental Health.
- [Woman] So what became of the Beautiful Ones?
Calhoun removed a group of them and put them in an enclosure
with fewer mice, and more space, plus a life time of clean
water and food.
The expectation was that they would revert
to normal behaviors.
- [Man] But the effects of societal collapse
were irreversible, something called the behavioral sink,
the point of no return, and Calhoun saw this with
The Beautiful Ones, who continued to groom their
days away, forever oblivious to one another.
Hey, if you enjoyed this video, be sure to check out these
three videos as well.
- [Woman] And don't forget to visit us at
StufftoBlowYourMind.com.
Rats, like humans, are one of the most resilient mammal
species on the planet,
and while they've long been maligned for their disease
vector shenanigans, these unlovable scamps
don't get the respect they deserve.
Yup, regardless of how you feel about one of nature's
most successful rodents, there's no denying that rats
are as intelligent as they are reviled.
They outsmart and escape laboratory experiments,
they experience empathy, and they've successfully
colonized every continent on Earth,
except for Antarctica.
And they'll get there soon enough, I imagine.
- [Man] If you want to understand how nurture and nature
play tug of war with our identities, all you have to do
is look at the world of mice.
In a new study from the University of Utah,
mother mice who competed for mates in a promiscuous
environment, went on to have sexier sons.
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