White tigers, green polar bears, & maintaining a world-class zoo
From ANIMAL PEOPLE, July/August 1995:
SINGAPORE––When the tigers
are white and the polar bears are a blotchy
dark green, a zoo has problems.
Opened in June 1973, the
Singapore Zoo and adjacent Night Safari are
together reputedly the best zoo complex with-
in half a global orbit, together setting the
Asian zoo design and management standard.
More than 1.2 million visitors per
year view about 3,200 animals of 330 mostly
tropical species at the Singapore Zoo and
The animals are chiefly housed in
semi-natural surroundings. The equatorial
Singapore climate is good for reptiles year-
round, including some of the largest tortoises,
most active monitors, and largest gharials and
salt water crocodiles on exhibit anywhere.
Pygmy hippos thrive. Both Old
World and New World monkeys and big cats
are uncommonly lively.
But there are jarring notes.
The Agri-Food & Veterinary
Authority of Singapore banned traveling wild
animal shows in 2002, yet the Singapore Zoo
and Night Safari still feature circus-like orang-
utan and marine mammal acts, opportunities
to hold and be photographed with young ani-
mals, and elephant rides.
Much of the educational signage is
The tiger exhibit, among the most
popular at the zoo, features intensively inbred
white tigers. Only a few white tigers have
ever been seen in the wild. Those in zoos are
virtually all close relatives of specimens bred
for show business.
And then, almost at the center of
the Singapore Zoo, stands the polar bear
exhibit. The exhibit looks much too small for
such large animals, but more is wrong.
Both bears, a mother and son, are
green from algae growing in their translucent
hair shafts. Some experts believe the algae
grows when the salinity of the bears’ habitat
varies from Arctic norms. Others hold that
the long Arctic night suppresses algae growth.
The Singapore Zoo in February
2005 washed the mama bear, Sheba, with
hydrogen peroxide. As of June 2005 she was
lime green. Her 13-year-old son, Inuka, was
more a forest green.
Changing color is apparently not a
problem for polar bears. The algal condition is
called “greening” regardless of what hue it
Tuk, the longest-lived polar bear on
record, was yellow when he rescued a kitten
from his moat at the Stanley Park Zoo in
Vancouver in 1983, and was still yellow when
he died on December 9, 1997, at age 37, hav-
ing long outlived the defunct zoo itself.
Tuk’s fur actually contributed to the
demise of the zoo. Though Tuk seemed con-
tent there, photos of the “green” bear became
a staple of literature distributed by the Vancou-
ver Green Party, whose slate closed the zoo
after winning election to the city parks board.
A greater problem at the Singapore
Zoo, from an animal welfare perspective, is
that the polar bears engage in stereotypical
pacing, a common predilection of understimu-
lated intelligent animals in zoos.
Zoo animals pace for many reasons,
and zoo critics often misread it. For example,
the anticipatory pacing of hungry animals at
feeding time may be called “stereotypical.”
Stereotypical pacing by polar bears,
however, tends to be obvious.
The most notorious case involved
Gus, the senior male polar bear at the Central
Park Zoo in New York City. Wildlife
Conservation Society behaviorist Don Moore
tried to stop his obsessive pacing for a decade.
“In 1994 the media observed Gus pac-
ing, and the public grew vocal and concerned
about his welfare,” Moore told a recent sym-
posium hosted by Polar Bears International.
“In 1998 the zoo became more proac-
tive, and put more soft substrates and frozen
food toys into the exhibit. Gus continued to
pace. The zoo then tried different types of
enrichment, such as sprayers, hay, logs, and
male fox scent. His pacing increased 33% with
the log and 121% with the male fox scent,”
“In 2002 the Zoo created a new polar
bear exhibit, ‘The Arctic Stream.’ Still, Gus
displayed no significant decrease in stereotypic
behavior. In 2003, Gus was given almost 24/7
access to the back den,” Moore ended. “This
change seems to have resulted in no pacing.”
North Carolina Zoo animal manage-
ment supervisor Tim Mengel found as far back
as 1996 that “24/7 den access decreased
stereotypical behaviors significantly. The
males’ stereotypies decreased by 62 and 66%,”
Mengel told the symposium, “while the
female’s decreased by 68%. In addition, the
bears’ object manipulation increased, and
social interaction increased slightly.”
But 24/7 den access is not the whole
answer. “When the zoo later made minor pool
modifications––smoothing rough surfaces and
a cobbled beach area, and turning off a loud
waterfall––stereotypes decreased even more.”
San Diego Zoo senior animal trainer
JoAnne Simerson tried to stop pacing polar
bears after a new San Diego polar bear exhibit
opened in 1996 seemed to produce more pac-
ing than the older, smaller facility had.
“When the zoo received two very
young, orphaned cubs and they too began to
exhibit early stereotypic behavior, zoo staff
came up with a theory they wanted to test,”
Simerson told the symposium.
“In the wild, cubs faced with novel
stimuli show a startle response and initial
stress reaction, followed by bonding or reas-
surance from their mother. Were zookeepers
coddling them too much, blocking the learn-
ing of coping skills, and unintentionally rein-
forcing the cubs’ stress-related reactions?
Were they entertaining the bears t o o m u c h ,
and not helping them entertain themselves?
“The cubs were crate trained,”
Simerson continued. “Trainers encouraged
their natural curiosity, but taught cubs to make
the connection that their behavior influenced
whether they got what they wanted.
“The trainers provided no food enrich-
ment, but created situations that would startle
the cubs, in hopes they would develop their
coping skills. For example, trainers intro-
duced the cubs to large vehicles, because
those are often driven around the exhibit area.
Keepers reinforced investigative behavior and
then reassured the cubs.”
Play increased from less than 10% to
more than 20% of the cubs’ time. Stereotypic
behavior decreased from 45% in 1997 to “less
than 0.08% in 2003,” Simerson said.
Oregon Zoo behaviorist David
Shepherdson from 2001 through 2003 studied
the activity of 59 captive polar bears at 22
accredited U.S. zoos.
“Males engaged in stereotypical
behavior more in the first two quarters of the
year,” Shepherdson reported. “Females
engaged in stereotypical behavior more in the
first and fourth quarters. The study found no
correlation between stereotypical behavior and
factors such as den access, exhibit complexity,
or wild-caught versus captive––except that
larger pool surface area (not volume) has a sig-
nificant positive effect.
“The more bears in a social group,
the less stereotypic behavior,” Sheperdson
found. “The more females in a
group, the less average time spent
The international zoo
community seems to have the exper-
tise to help the Singapore Zoo build
a world-class polar bear habitat.
The catch is not necessarily money.
“Polar Bear Splash” at the
San Diego Zoo cost $5 million in
1996. “Arctic Ring of Life,” at the
Detroit Zoo, cost $13.6 million in
2001. Replacing the present Singapore Zoo
polar bear house with anything comparable
could cost $20 million or more.
But “The Arctic Stream” was added
to the Central Park Zoo for Gus at cost of just
$25,000 for expansion of his habitat, plus the
donation of a $12,500 current-churning
machine by Endless Pool Inc.
“Since April 2004 we have been in
discussion with the Singapore Zoo with regard
to their polar bears,” Animal Concerns
Research & Education Society president Louis
Ng told ANIMAL PEOPLE.
“We had originally asked that the
bears be repatriated to the Cochrane (Ontario)
polar bear facility, which is a rescue centre for
polar bears,” at a historical theme park, Ng
said. “The zoo was keen, but has now decid-
ed that they want to keep the bears.
“They have also indicated that they
will not build a new enclosure,” Ng added.
“The existing enclosure is difficult to improve
to any acceptable standard as it is simply too
small and nothing much can be done. We are
now looking to compile a detailed report on
polar bears in captivity in Asia,” including
examinations of exhibits in Thailand, China,
Japan, and South Korea.”
ACRES and Ng are also in conflict
with the Singapore Zoo over their effort to
extend the 2002 circus ban to the zoo acts.
From a business management per-
spective, Ng is simultaneously pressuring the
Singapore Zoo to undertake costly improve-
ments and threatening revenue streams that
could help pay for them.
From a zoo management perspec-
tive, however, Ng is only asking the
Singapore Zoo to catch up with the standards
and practices that have evolved among major
U.S. zoos in the decades since it debuted.
Orangutans do not normally perform
tricks before crowds. Zoos have learned that
crowds will come to see them if they merely
go about their own business. The public will
admire elephants, whether or not they can be
ridden. Yellow and black tigers are every bit
as magnificent, and genetically healthier than
white tigers. Even green polar bears do not
have to pace.
Knowing this is what distinguishes a
state-of-the-art zoo today from the state of the
art when the Singapore Zoo debuted.