The #1 source for news about monkeys and apes

[Josh Greenman <josh.greenman AT gmail.com>]

http://www.economist.com/node/16963942

Zoos and apes: Behind the curtain

Zoos are better places for animals than they used to be. But more
still needs to be done

Sep 3rd 2010

ONCE, they were grim places of bars and concrete. But zoos today are,
more often than not, places where endangered species are bred in
verdant and naturalistic enclosures. At least, that is what the public
sees. As night falls and the facilities need to be cleaned, the
animals are commonly led into small concrete holding areas. For
decades zoos around the world have used such areas without question
and assumed that their effects on the animals’ behaviour were
negligible so long as high-quality enclosures were available during
the day. This notion may, however, be wrong, for a new study shows
that, at least among the great apes, holding areas have a dramatic
effect on behaviour.

While working with chimpanzees and gorillas, Stephen Ross, a
primatologist at Lincoln Park Zoo in Chicago, noticed that the animals
changed their behaviour when they were moved in and out of the holding
areas. Curious as to whether these changes were happening regularly,
and keen to identify specifically how behaviour was changing, Mr Ross
and a team of his colleagues decided to carry out an experiment.

The researchers trained observers to monitor seven chimpanzees and
seven gorillas in both the holding areas and the enclosures. These
observers did so for 15 months. Every day, the apes spent two hours in
their holding areas, which had a floor area of 11 square metres, and
the rest of the time in their enclosures, which were ten times this
size. Both the holding areas and the enclosures were indoors.

While doing their work, the observers sat quietly near the animals and
noted down their behaviour. When the apes were on public view, the
number of visitors present was also noted. In total, the observers
collected 208 hours of observations in the enclosures and 73 hours in
the holding areas.

Mr Ross and his colleagues report in the American Journal of
Primatology that among their chimpanzees, aggressive behaviour
increased when the animals were placed inside holding areas. Chimps
spent about 0.1% of their time being aggressive when they were in the
enclosures. That rose to 0.5% when the animals were in the holding
areas. The researchers also found that chimps scratched and groomed
themselves much more. Scratching increased fourfold. Chimps spent 0.4%
of their time in the enclosures having a scratch. That went up to 1.6%
in the holding areas. Self-grooming, a gentler activity than
scratching, increased from 12.3% to 17.4%. In contrast, time spent
foraging for food dropped from 18.1% of the total in the enclosures to
10.5% of it in holding areas.

Gorillas showed a drop in foraging as well. It fell from 30.6% of
their time when in the enclosures to 5.4% in the holding areas. But
they also showed numerous changes of behaviour that were different
from those seen in chimpanzees. Most notably, they became more
affectionate rather than more aggressive when in the holding areas.
Behaviours such as grooming other individuals, playing with them and
embracing them rose from 4.1% of their time to 8.2%. The animals also
moved around much more, spending 11.6% of their time on the move in
the holding areas, but only 7.2% in the enclosures. Neither species,
though, seemed to mind being watched. The number of visitors outside
an enclosure had no effect on the behaviour of the animals within it.

Mr Ross argues that interpreting the chimpanzee data is
straightforward. Scratching and self-grooming are well known to be
related to anxiety. That they increase in frequency in holding areas
suggests the chimpanzees feel bad in these places. The increase in
aggression and decrease in foraging also support this hypothesis.

The gorilla data, by contrast, are anything but straightforward. That
holding areas saw gorillas foraging less suggests the animals do not
like them. Yet friendly behaviour and moving around (which is also
regarded as a positive activity in gorillas) happened more often in
holding areas, which suggests they were happy there.

While the gorilla data will require further analysis before any clear
conclusion can be drawn, the discovery that great apes’ behaviour
changes when they go into holding areas is important. Hundreds of
reports about the behaviour of animals in modern zoos support the idea
of building complex enclosures. If animals come under stress when put
in holding areas, though, the benefits of these enclosures may be
reduced.

Although Lincoln Park Zoo puts its chimpanzees and gorillas in such
areas for only two hours a day, a survey that Mr Ross conducted of the
management practices for chimpanzees in other zoos accredited by the
Association of Zoos and Aquariums suggests that is unusual. Some 85%
of the institutions that responded reported that their chimps spend
more than 12 hours a day in holding areas. And this is only what
happens in accredited zoos. In America alone there are also more than
1,800 chimpanzees in unaccredited zoos, sanctuaries, laboratories and
private homes. Compared with some other places, two hours a day in the
cooler may be paradise.