White tigers, green polar bears, & maintaining a world-class zoo
From ANIMAL PEOPLE, July/August 2005:
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 within half a
global orbit, together setting the Asian zoo design and management
More than 1.2 million visitors per year view about 3,200
animals of 330 mostly tropical species at the Singapore Zoo and Night
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 orangutan and marine mammal acts,
opportunities to hold and be photographed with young animals, and
Much of the educational signage is decades obsolete.
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
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, having long outlived the defunct zoo itself.
Tuk’s fur actually contributed to the demise of the zoo.
Though Tuk seemed content 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
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 understimulated intelligent animals
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 pacing, and the public grew
vocal and concerned about his welfare,” Moore told a recent
symposium hosted by Polar Bears International.
“In 1998 the zoo became more proactive, 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,” Moore said.
“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
North Carolina Zoo animal management 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.” Mengel said.
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 pacing than the older, smaller
“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
reassurance from their mother. Were zookeepers coddling them too
much, blocking the learning of coping skills, and unintentionally
reinforcing the cubs’ stress-related reactions? Were they
entertaining the bears too much, and not helping them entertain
“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 enrichment, but created
situations that would startle the cubs, in hopes they would develop
their coping skills. For example, trainers introduced the cubs to
large vehicles, because those are often driven around the exhibit
area. Keepers reinforced investigative behavior and then reassured
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
“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
significant 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 stereotyping.”
The international zoo community seems to have the expertise
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 decided 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 perspective, Ng is simultaneously
pressuring the Singapore Zoo to undertake costly improvements and
threatening revenue streams that could help pay for them.
From a zoo management perspective, 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
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.