“These animals know so much about
each other’s relationships, and it’s conceivable that this type of social cognition
is very important in being able to establish and maintain bonds,” Cheney says.
“Which would suggest that there is real
evolutionary advantage to, in a sense,
being a social wire and being highly
motivated to know about each other.”
Got your back
Scientists have long known that animals form bonds. Primates and horses
that spend more time in close proximity
will generally be friendlier and less
aggressive with each other. Chimps
and elephants share food, comfort the
injured and appear to grieve at the deaths
Still, for decades the prevailing
view was that most interactions occur
between closely related individuals.
Bonds formed between unrelated animals were supposedly only transient,
designed to gain some immediate benefit. Scientists now know that isn’t true.
Studies of dolphins, horses, lions and
chimpanzees show that even unrelated
animals often form stable bonds lasting
for years. And evidence indicates that
one animal may do something costly
to help a nonrelative, while receiving a
Such exchanges, known as contingent
cooperation, operate daily in human
relationships, says biologist Liza
Moscovice of Binghamton University
in New York. “You might buy coffee for
your coworkers, but you expect that at
some point they’re going to buy coffee
for you too,” she says.
Though it remains unclear whether
nonhuman animals keep track of all
the favors they give and receive, experiments suggest that contingent cooperation plays a big role in their relationships.
In 2010, Moscovice and Cheney, along
with others, showed that a shared positive experience can increase the odds
that one individual will help the other
at another time.
Among the female baboons studied,
the primary way of bonding is through
grooming. Grooming entails sitting with
another and methodically cleaning her
fur, a task that provides an immediate
benefit to the animal being groomed.
“It’s like getting a hug,” Moscovice says.
Hobnobbing chimps Male chimpanzee pairs that engaged in friendly behavior more often
than expected by chance were more likely to be distantly related (blue) than closely related (tan).
the findings suggest chimps are motivated to cooperate with nonrelatives, not just close kin.
Cooperative behavior among chimp pairs
Percent of pairs
April 7, 2012 | SCIENCE NEWS | 19