The Ecology Book

125

Bonobos are very social primates.

Their capacity for empathy makes

them less aggressive and may align

them more closely with their human

cousins than the common chimpanzee.

ranking males called Charlie and

Hugh and causing them to split

off with some other chimps to the

south. The two groups became

more and more separate, feeding

in different parts of the forest. At

first there was the odd aggressive

skirmish and then war broke out.

Over four years, Humphrey and his

cohorts killed every male in the

southern group and took over their

territory, as well as three surviving

females. It is thought that the full-

blown war may have been due

to a lack of mature females in the

northern group. Power struggles

and fighting over a female all sound

very human.

Fights over resources

The long-running war witnessed

by Goodall is the only sustained

conflict among chimpanzees to

have been fully documented,

but violence within chimp

communities has been recorded

many times. Chimps have been

observed stealing and killing baby

chimps and rounding on a disliked

alpha male. In communities studied

in Uganda, males routinely beat

the females they mate with. It is

thought that this violent streak

running through chimps may be

associated with food resources and

meat eating. When food is limited,

the chimps become more violent

in order to obtain the resources

they need. Chimps are known to

eat more meat when fruit is scarce.

Kissing cousins

The link between food scarcity

and aggression in the common

chimpanzee may explain why our

other evolutionary cousin in the

primate world, the bonobo (pygmy

chimp), is so peace-loving. These

small, placid chimps are omnivores

but live in an environment where

fruit is plentiful most of the time.

They forage in groups, and tend

to use sex to relieve tensions in

social situations. Conflict is rare

in bonobo societies, which are

also matriarchal, unlike the male-

dominated chimp communities.

An experiment carried out by

researchers at Duke University,

North Carolina, in 2017 showed

that bonobos are also altruistic. Two

bonobos (unknown to each other)

were put in adjacent rooms (A and B)

with a fence between them and a

THE VARIETY OF LIFE

piece of fruit hanging over one room

(B). The bonobo in room A could

release the fruit but not get to it

himself. The researchers found that

this bonobo would consistently

release the fruit, so that the other

one could reach it, helping a

stranger, with no reward for himself.

Researchers also observed how

the sight of an unknown bonobo

yawning in a film would trigger

a yawning response in bonobos

watching the film, suggesting a

capacity for empathy. Other studies

have shown how bonobos comfort

each other when in distress. Unlike

the “negative” behavior that

humans share with chimps,

these traits mirror more laudable

human characteristics, such as

compassion. Understanding such

behavior in bonobos could shed

light on how our human social

behavior developed. ■

I’m determined my

great grandchildren

will be able to

go to Africa and

find wild great apes.

Jane Goodall

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