Wild chimps outwit human hunters
By Matt Walker
Quick learners: chimps approach and touch the snares, on these occasions
without breaking them (video courtesy of Gaku Ohashi)
Wild chimpanzees are learning how to outwit human hunters.
Africa, people often lay snare traps to catch bushmeat, killing or injuring
chimps and other wildlife.
But a few chimps living in the
rainforests of Guinea have learnt to recognise these snare traps laid by
human hunters, researchers have found.
More astonishing, the chimps actively seek out and intentionally
deactivate the traps, setting them off without being harmed.
The discovery was serendipitously made by primatologists Mr Gaku Ohashi
and Professor Tetsuro Matsuzawa who were following chimps living in Bossou,
Guinea to study the apes' social behaviour.
Snare injuries to chimps are reported at many sites across
east and west Africa where chimps are studied, with many animals dying in the
traps. However, very few snares injuries have been reported among chimps studied
at Bossou, which is unusual as the chimps live close to human settlements and
snares are commonly laid in the area. Now primatologists know why.
researching the chimps, Mr Ohashi and Prof Matsuzawa, of the Primate Research
Institute at Kyoto University, Japan, observed five male chimps, both juvenile
and adult, attempting to break and deactivate snares. On two occasions
witnessed, the chimps successfully deactivated the traps set for them.
A typical snare, for example one made by the Manon people of
Bossou, consists of a loop of iron wire connected by a vine rope to an arched
stick, often a sapling.
On six separate occasions, chimps attempted to deactivate the traps
The sapling puts tension into the rope and once an animal passes through
the wire loop, the trap is sprung and the sapling pulls it tight, around the
neck or leg of an animal.
Such traps cause indiscriminate damage,
ensnaring any and all animals that come into contact with them.
male Bossou chimps have worked out how to outwit the hunters and deactivate
"They seemed to know which parts of the snares are
dangerous and which are not," Mr Ohashi told the BBC.
A rat caught in a snare is found by researchers
In the journal Primates, the researchers describe six separate cases
where chimps were observed trying to deactivate snares.
chimps grasped the snare stick with their hands, shaking it violently until
the trap broke.
Sometimes a chimp lightly knocked the sapling that
holds the snare, before grasping it to break the trap.
But in all
cases, they avoided touching the dangerous part, the wire loop.
video above, chimp can be seen seeking out and inspecting snares, without
"We were surprised when we found this behaviour,"
says Mr Ohashi.
"This is the first report of chimpanzees breaking
snares without injury."
The chimps' actions may also reveal
something important about how chimps learn.
Often, chimps acquire
new talents by trial and error.
For example, when trying to crack
nuts, they might strike one stone onto an anvil stone and miss the nuts all
together. Or they might use their hands to strike the nut, which is
But the Bossou chips couldn't have learned how to deactivate the snares
this way, as one mistake could be fatal.
"The observations indicate
that chimpanzees can learn some manners without trial and error," says Mr
The researchers speculate that the chimps may have learnt
how the snares work by observing them over time, and this information has
been passed down generations.
During one case, a juvenile male
watched an adult male deactivate a snare, before then moving in to handle it
once it was safe.
The researchers caution that snares remain a
significant threat to wild chimps, and they are leading conservation efforts
to scan the forest for the traps and remove them.
They also say that
chimps in other regions do not appear so far to have also learnt how to
outwit human hunters in this way.