Many animals are known to use tools, but a bird named Bruce may
be one of the most ingenious nonhuman tool inventors of all: He is a disabled
parrot who has designed and uses his own prosthetic beak.
اضافة اعلان
Bruce is a kea, a species of parrot found only in New Zealand.
He is about 9 years old, and when wildlife researchers found him as a baby, he
was missing his upper beak, probably because it had been caught in a trap made
for rats and other invasive mammals the country was trying to eliminate. This
is a severe disability, as kea use their dramatically long and curved upper
beaks for preening their feathers to get rid of parasites and to remove dirt
and grime.
But Bruce found a solution: He has taught himself to pick up
pebbles of just the right size, hold them between his tongue and his lower
beak, and comb through his plumage with the tip of the stone. Other animals use
tools, but Bruce’s invention of his own prosthetic is unique.
Researchers published their findings Friday in the journal
Scientific Reports. Studies of animal behavior are tricky — the researchers
have to make careful, objective observations and always be wary of bias caused
by anthropomorphizing, or erroneously attributing human characteristics to
animals.
“The main criticism we received before publication was, ‘Well,
this activity with the pebbles may have been just accidental — you saw him when
coincidentally he had a pebble in his mouth,’” said Amalia P.M. Bastos, an
animal cognition researcher at the University of Auckland and the study’s lead
author. “But no. This was repeated many times. He drops the pebble, he goes and
picks it up. He wants that pebble. If he’s not preening, he doesn’t pick up a
pebble for anything else.”
Dorothy M. Fragaszy, an emerita professor of psychology at the
University of Georgia who has published widely on animal behavior but was
unacquainted with Bruce’s exploits, praised the study as a model of how to
study tool use in animals.
“The careful analyses of the behavior in this report allow
strong conclusions that the behavior is flexible, deliberate and an independent
discovery by this individual,” she said.
The researchers set themselves careful rules.
First, they established that Bruce was not randomly playing with
pebbles: When he picked up a pebble, he used it for preening 9 times out of 10.
When he dropped a pebble, 95 percent of the time he either retrieved it or
picked up another one and then continued preening. He consistently picked up
pebbles of the same size, rather than sampling pebbles at random.
None of the other kea in his environment used pebbles for
preening, and when other birds did manipulate stones, they picked pebbles of
random sizes. Bruce’s intentions were clear.
“Bruce didn’t see anyone do this,” Bastos said. “He just came up
with it by himself, which is pretty cool. We were lucky enough to observe this.
We can learn a lot if we pay a little more attention to what animals are doing,
both in the wild and in captivity.”
Kea in general are quite intelligent, but Bastos said Bruce was
clearly brighter than other birds, very easily trained in fairly complex tasks
in addition to developing his own ideas. Bastos said she was sometimes asked
why she didn’t provide Bruce with a prosthetic beak.
“He doesn’t need one,” she always responds. “He’s fine with his
own.”
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