The Misunderstood Rat
Rats are one of the world’s
least understood creatures. Stigmatized as filthy “pests”
for centuries, these inquisitive opportunists are actually naturally
sociable and make excellent companions. New scientific studies show
that there is more to rats than laboratory supply companies would
have us believe.
Rats love to play, especially when young. During play, rats’
brains release large amounts of dopamine and opiates (in people,
these chemicals are associated with pleasure and excitement).1 They
chirp with apparent joy both during play and in anticipation of
it,2 and one distinguished neuroscientist believes these chirps
are a rat version of laughter.3
Rats are also tactile. They will nip gently to solicit tickles
and strokes from trusted human companions.2 In a carefully controlled
laboratory study at Bowling Green State University, rats accustomed
to tickling ran to the hand four times as quickly as did petted
rats and made seven times more chirps. The difference increased
over the five-day period, suggesting a growing enthusiasm for being
tickled.4 In the same study, each rat was presented with two metal
bars, only one of which offered a tickling reward when pressed.
The animals pressed the tickle bar repeatedly, but almost never
pressed the other bar.4
Rats also play fair. When researchers at the University of Lethbridge
analyzed video footage of playing rats, they found that individuals
assess and monitor one another, then fine-tune their own behavior
to maintain the play mood.5 Playing rats restrain themselves when
they know their actions would cause pain to another individual.6
The cooperation and fairness required of play may form the basis
for a sense of right and wrong and the rudiments of moral behavior.7
Like humans, rats appreciate variety in their food. A 2003 study
found that rats (and hamsters) favored new foods following several
days’ exposure to a single food.8 Rats will also enter a deadly
cold room to retrieve highly palatable food, even though their regular
chow (which is dry and monotonous) is available in their cozy nests.9
This is a rodent version of shunning the fruit bowl and dashing
out for donuts on a wintry night.
These studies show that rats are not as different from us as some
might think. Not only do they try to avoid painful or stressful
situations, they seek out pleasurable ones. They look forward to
a good game, they obey rat rules of social conduct, and they have
preferences. These traits constitute more reasons why these sensitive,
intelligent animals should not be subjected to harmful experiments.
References:
1 Panksepp, J. 1998. Affective Neuroscience.
Oxford University Press.
2 Knutson B, Burgdorf J, Panksepp J. 1998. Anticipation
of play elicits high-frequency ultrasonic vocalizations in young
rats. Journal of Comparative Psychology 112: 65-73.
3 Panksepp J, Burgdorf J. 2003. “Laughing”
rats and the evolutionary antecedents of human joy? Physiology &
Behavior 79: 533-47.
4 Burgdorf J, Panksepp J. 2001. Tickling induces
reward in adolescent rats. Physiology & Behavior 72: 167-173.
5 Pellis S. 2002. Keeping in touch: Play fighting
and social knowledge. In Bekoff M, Allen C, and Burghardt GM (eds.)
2002. The Cognitive Animal Cambridge, Mass: MIT Press.
6 Church F. 1959. Emotional reactions of rats to
the pain of others. Journal of Comparative and Physiological Psychology
52: 132-134.
7 Bekoff, M. Wild justice, cooperation, and fair
play: Minding manners, being nice, and feeling good. In R. Sussman
and A. Chapman (eds.) The Origins and Nature of Sociality. Aldine,
Chicago. pp. 53-79.
8 Galef BG Jr, Whiskin EE. 2003. Preference for
novel flavors in adult Norway rats (Rattus norvegicus). Journal
of Comparative Psychology 117: 96-100.
9 Phillips H. 2003. The pleasure seekers. New Scientist
October 11: 36-40.
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