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The other day I received a satellite phone call from my research
site in the wild, Bossou, Guinea, West Africa. The call was to
inform me of the birth of a chimpanzee infant that took place
around the middle of May, 2001. As with all Bossou chimpanzees,
the infant's name was chosen by the local assistants. They named
the newborn "Veve". Veve's mother, Vuavua is a 10-year-old
female. The average age of first delivery in the wild is estimated
at 13 to 14 years old, making Vuavua somewhat of a record-holder.
The addition of the new infant to the community means that Bossou
is now home to 21 chimpanzees. 
The phone call was from Tatyana Humle, a student at the University
of Stirling, UK. She had just arrived in Bossou to carry out
research continuously for 6 months. It is still somewhat of a
novelty for me to be able to receive information about Bossou
- with the aid of a satellite phone - while sitting in my office
in Japan! The conditions under which research in the wild is
conducted nowadays is certainly a far cry from the situation
15 years ago, the time of my first visit to Bossou.
My earliest encounter with Vuavua took place in January 1992.
She was a tiny infant at the time, less than 6 months old. Her
mother, Velu held her tightly against her breast. Over the years
that followed, I watched Vuavua's progress with interest. She
spent much of her time with two play-mates of similar age: Fotayu
and Yoro - the three of them practically grew up together. When
I think back, I remember many scenes about Vuavua. Perhaps the
most impressive among these was an episode I call "doll
play".
Around 5:00PM on January 18th 2000, we heard loud screams in
the forest. A male chimpanzee, Yoro, caught a live hyrax, which
elicited much general excitement among the group. Sounds of fighting
continued to be heard for half an hour. Finally, peace returned
and when we next saw the hyrax it was dead - we spotted Vuavua,
8 years old at the time, climbing up a tree, with the lifeless
animal in her grip.
She held the dead body in her hand. She held it with her foot.
She carried it on her back or in the "groin pocket"
situated between her belly and leg. As evening approached, she
set out to make herself a nest for the night using the leafy
branches of a tree, at a height of about 10m. When she finished,
she lay on her back with the hyrax in her arms. She started to
groom the body with her fingers and lips, and held it up in the
air with her hands and feet. We continued to observe her until
late in the evening. When, at last, she went to sleep, she did
so while holding the hyrax.
The next morning, we set off in search of Vuavua. We came upon
her in roughly the same place where we'd left her the night before
and found that she was still holding the dead animal. It eventually
took until noon of the same day before she finally gave up carrying
the hyrax and abandoned it in a bush. We were able to retrieve
the body: the animal was 42cm in length and weighed 2.3kg.
There are reports from other sites in Africa where chimpanzees
have been known to sometimes kill hyraxes and eat them. Although
chimpanzees at Bossou also catch hyraxes, they never eat them.
What's more, instead of turning it into a meal, Vuavua in this
case decided to treat the dead animal as a toy!
This wasn't the only time we observed "doll play" at
Bossou. Another female chimpanzee, Ja, starred in the following
fascinating observation. She was 8 years old at the time - the
same age as Vuavua in the previous episode. She was walking after
her mother who was carrying Ja's 2.5-year-old younger sibling.
Ja wasn't empty-handed either: following her mother's example,
she carried a large branch with her, about 50cm in length and
10cm in diameter. She held the branch doll at her side with her
arm, as if it were an imaginary infant.
If you observe wild chimpanzees for a long time, you will be
able to identify common features or patterns of behavior even
if individual episodes at first look very different from each
other. During my work in the wild, I came across scenes such
as the two described above only very rarely, yet I can find parallels
between them and with confidence refer to both as examples of
"Doll play". Young female chimpanzees treated objects
- a branch or a dead animal - as if they were handling real infants.
In a way, such doll play behavior is good practice for the future,
for bringing up your own young.
Our observations in the wild are limited to fragments of the
chimpanzees' daily lives. The news of Vuavua's first delivery
brought back a lot of memories from past years. I was delighted
to learn that she had become a fine mother.
photo : A 8-year-old female chimpanzee at Bossou named
Vuavua holding a hyrax as a doll (photo by Satoshi HIRATA)
references:
AJP paper by Hirata et al. (2001) Capturing and toying with hyraxes
(Dendrohyrax dorsalis) by wild chimpanzees (Pan troglodytes)
at Bossou, Guinea. American Journal of Primatology, 53: 93-97 |
Essay on evolutionary neighbors