Righteous rats.

• Position: BEHAVIOR - Rats' behavior - Brief article

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Rats may be more caring and selfless than their reputation as "low-down dirty rats" suggests. It turns out that rats can be very kind to each other--even to rats they haven't met before. Swiss researchers put pairs of female rats that were litter-mates in a cage, separated in haft with a wire mesh.

On one side of the barrier, a rat could pull a lever that would deliver food to her sister on the other side, but not to herself. Each rat was trained in alternate sessions--first as a recipient of food, then as a provider. The rats would pull the lever more often when their litter-mate was present than when the other haft of the cage was empty. Researchers then put rats who had been fed by their partners in the cage with unrelated...