Modern Zoos

It’s not Australia, but koalas feel at home. If you are the sort of person who complains about overly large zoo exhibits that allow animals to stray from the most prominent viewing areas, you should take a closer look at what these wildlife parks are trying to accomplish. As “Gorilla Tropics,” “Polar Bear Plunge,” and other San Diego Zoo areas demonstrate in Animal Attractions, the zoo is not a “living museum,” but a place where animals should feel at home. Today, zoos combine educational exhibit areas with backstage research areas where zoologists study the animals under their care.

Visitors are captivated by animals at the zoo. During the latter part of the 20th century, zoos began to provide a new experience for visitors by replacing the iron bars and concrete walls of cages with protective moats, bigger animal areas, and recreated tropical rainforests. The San Diego Zoo, founded in 1916, helped pioneer this shift.

Zoos used to keep all animals in cages. In 1868, Chicago’s Lincoln Park Zoo was reportedly the first zoo in the United States to open its gates to the public, followed closely by the Philadelphia Zoo and New York’s Central Park Zoo. These parks filled their cages with wild-caught animals. As the burgeoning populations and growing industries of the 20th century began decimating wild habitats, zoos took on the role of housing remnants of once-thriving animal populations.

Then in 1907, Carl Hagenbeck, of the Tierpark in Hamburg, Germany, thought of using moats rather than bars to enclose animals, but this trend took more than a few years to catch on. Dr. Harry Wegeforth, founder of the San Diego Zoo, was determined to create moated exhibits, and in 1922, the first lion area opened, free of any enclosing wires. At first, visitors were afraid that the lions would escape and attack them.

Today, a walk through the Bronx Zoo’s “Wild African Plains” exhibit shows how this technique offers the public a seamless view of animals coexisting, as if side by side in the wild. The African antelope and its predator, the lion, appear to be in the same field, when in fact they are separated by a deep, wide gully. This type of gap deters the lions from hunting the antelope — not to mention hunting the visiting humans

An even better simulation of the safari experience takes place at the San Diego Wild Animal Park. Here, photo caravans transport tourists through a pasture of giraffes, zebra, ostriches, rhinos, and many other species visitors might have had to travel to Africa or Asia to see in the wild. But unlike a real safari, here visitors may safely feed the animals, which have been tamed through repeated human interaction and, in fact, seem to look forward to visits. This 2,200-acre park is home to more than 2,500 animals.

But since that kind of acreage is oftentimes not available, architects struggle to make exhibit areas spacious and interesting to their inhabitants and visitors. Since the 1960s, zoo horticulturists have built naturalistic habitats that reach new levels of creativity. A big issue is that of “psychological space” — the idea that the animal should feel that it is actually in the wild. Examine the case of the San Diego Zoo’s “Polar Bear Plunge,” featured in the NATURE program, which took two years and seven million dollars to build.

There is no way a zoo near a major city can approximate the vast distances of the Arctic. So, instead, the zoo architects who designed “Polar Bear Plunge” tried to give the bears a stimulating, varied environment that would prevent them from becoming bored. Zoo keepers provide toys and puzzles (such as fish stuffed into a column of ice for the bears to dig out), slides, pools, and streams, all in an effort to make the polar bears feel at home.

But designers must also keep the safety of the public in mind. Polar bears are, after all, powerful, 10-foot-tall wild animals capable of causing serious harm to people. The zoo walled the bears behind solid concrete and constructed a thick glass barrier, so visitors could watch the bears underwater and feel that they were getting as close to them as possible. Interestingly, they found out that the bears seem to be as fascinated by the public as the public is by them.

According to Fred Beiner, president of the Association of Zoological Horticulture, designers must tackle issues of insect control, drainage, plant toxicity, and durability, and also must depict the animal’s natural habitat accurately and provide it with an interesting environment. Most importantly, he states, a good zoo exhibit should combine these elements with a clear view of the animals for the public and educational signs that describe what they see.

Nature vs. Nurture

During the 20th century, as humans have encroached more and more on animals’ territory, zoos have come to be more than just places to view wild animals. They have become breeding facilities, wild animal hospitals, and research centers. As you see in Animal Attractions: Amazing Tales from the San Diego Zoo, a lot goes on behind the scenes, away from the ordinary visitor. And much of this activity is focused on a single goal: trying to save species from extinction.

The thought behind this idea is that as humans have spread across the globe, the breeding, migratory, and behavior patterns of wild animals have been forever changed. Since we cannot put the world back the way it was, scientists reason, we must try to invent new ways to deal with the problem of endangered animals, some of whose ranks have dwindled to the double — or even single — digits.

The Species Survival Plan (SSP) is sponsored by the American Zoo and Aquarium Association (AZA). The plan’s aim is to help “ensure the survival of selected wildlife species” through cooperative captive-breeding and training programs. Zoos share animals with other zoos, which keeps gene pools diverse as well as increasing the chances of conception in the event that a particular male and female don’t seem to have the right “chemistry.”

The Center for Reproduction of Endangered Species at the San Diego Zoo is headquarters for the SSP of the giant panda. If the resident pandas are not on exhibit at the zoo, they are probably under the scrutinizing eye of researchers studying their behavior. This program, headed by scientist Dr. Don Lindburg, began in 1987 as a long-distance collaboration with Chinese scientists at the Woolong Giant Panda Conservation Centre in Sichuan Province, China. This rare species faces the double threat of habitat fragmentation and illegal hunting, even though the latter carries the steep penalty of execution in China. Today, an estimated 1,000 pandas survive in the remote bamboo forest areas of the Qionlai Mountains.

In September, 1996, Lindburg’s team became foster keepers for a 15-year-old rescued male named Shi Shi and a six-year-old captive-born female named Bai Yun, both on loan from Woolong. The pair was introduced in February, 1997, in the hopes that when Bai Yun was ready to mate, Shi Shi would accept her.

They noticed each other, and it was not friendly, but it was not aggressive either,” describes Lindburg of the pandas’ first meeting. “It is sort of what you would expect from a solitary animal.” Wild pandas are rarely found in pairs, unless a mother is nursing a youngster or a couple is about to copulate. To put the pandas “in the mood,” Lindburg rotated them in each other’s play spaces, recording their reactions to various aromas placed in the environment. He eventually put the pair together.

“What happened was that the female became very solicitous,” says Lindburg. “Unfortunately, the male basically ignored her, and then responded to all of her overtures in an unfriendly manner.” Shi Shi growled, chased Bai Yun away, and swatted at her.

This means the researchers will have to wait a whole year to run the process all over again: females receive males only once a year for two or three days, attracting them with a “panda perfume” in the form of scent markings on trees or the ground. Scientists believe that this method is one of the main reasons pandas face extinction: their habitats, once solid swaths of forest, have been split up by a sprawling human population. Now pandas cannot find each other during the crucial one to two days when the female is in season.

Meanwhile, Lindburg and his colleagues are studying Bai Yun and Shi Shi intensely, hoping that their behavior will give researchers a clue as to how to boost the falling population of pandas in the wild.

Update: On Auguest 21, 1999, Shi Shi gave birth to Hua Mei, the first giant panda born in the Western Hemisphere since 1990. On February 11, 2000, visitors to the San Diego Zoo were able to get a glimpse of the baby panda.

NATURE takes you an a whirlwind tour of the animal kingdom as we explore the World-Famous San Diego Zoo and Animal Park.

Every animal has a story…and so does the staff at the San Diego Zoo. NATURE’s presentation of Animal Attractions: Amazing Tales from the San Diego Zoo invites you to look through the eyes of those who work behind the scenes, making sure every animal is properly cared and provided for.

From tiny Imani, a prematurely born and desperately ill gorilla baby, to fiercely independent and aggressive Nola, a 25-year-old northern white rhinoceros, the animals at the Zoo have all experienced the nurturing care of its deeply involved staff. Involved not only in the individual animals’ lives, but in ensuring the continued survival of the Earth’s most endangered species, such as the giant panda and the California condor. Whether it means finding out the secret to encouraging Bai Yun and Shi Shi (the only giant panda pair on the continent) to mate, or introducing dramatic procedures into the relationship between male and female white rhinos, those who keep the Zoo running are determined to keep these populations alive and healthy.

Get caught up in the drama of veterinary medicine at the Zoo, celebrate each triumph and mourn each loss, all against the backdrop of life in the practically wild.

To order a copy of Animal Attractions: Amazing Tales from the San Diego Zoo, please visit the NATURE Shop.

Online content for Animal Attractions: Amazing Tales from the San Diego Zoo was originally posted February 2000.

Animal Medicine

Some of the most gripping scenes in the NATURE program Animal Attractions show the drama of veterinary medicine at the San Diego Zoo and Wild Animal Park. Animal health care is an important part of the zoo’s mission, and staff members pay daily “house calls” to residents. Whether an infant gorilla is struggling for life, a cheetah is giving birth to a premature litter, or a white rhino is receiving hormone therapy, every creature’s case is taken very seriously in the zoo’s “animal E.R.”

Imani, a western lowland gorilla born at the zoo in 1997, arrived in the intensive care unit within 72 hours of her birth. The two-pound infant was weak and tiny, less than half the weight of a normal newborn gorilla. In addition, her blood showed dangerously high levels of bilirubin, a toxin that can cause brain damage.

Imani was bottle-fed, given ultraviolet light treatments to flush the bilirubin from her system, and watched as carefully as any human preemie. For days, veterinarians held their breaths: Would Imani make it? Luckily, they were able to stabilize the tiny primate, who grew to be a healthy toddler. When she joined the others in the zoo’s “Gorilla Tropics”, she was adopted by Alvila, an older female, and welcomed to the family.

A few months after Imani’s successful recovery, a cheetah went into labor. The mother had lost her previous litter, so zoo veterinarians decided to perform surgery to remove the four cubs inside her womb. The cheetah was put under anesthesia in preparation for her Caesarian section.

One by one, veterinarian Dr. James Oosterhuis drew out the tiny cubs from the mother’s open belly and cleaned off the protective sacs that held them. But something was wrong: the cubs were not breathing. Four veterinarians immediately began blowing baby-size breaths into the infants’ mouths and massaging their floppy bodies to stimulate their organs until the newborns began to squeal. The infants were placed directly into the incubator to gain strength. Sadly, the cubs’ luck did not hold. Too weak to withstand infection, the cubs died within the week. But Oosterhuis is hopeful that next time, the mother cheetah will be able to give birth successfully.

The northern white rhinoceros is in terrible danger of extinction: only about 30 remain in the world. The San Diego Wild Animal Park introduced Nola, a female who had never borne offspring, to Angie, a male who had travelled all the way from a zoo in Sudan. The veterinarians hoped he would become her mate. But at the relatively old age of 25, Nola was a tough customer.

Fierce and aggressive, she repelled Angie’s overtures, actually bowling him over when he tried to get to know her better. Hormone therapy brought Nola into heat, but did nothing about her continued aggression. Wild Animal Park workers knew something drastic had to be done. A decision was made to saw off her horn in the hopes that without it, Nola might be more receptive — and less dangerous — to Angie. After anesthetizing Nola for the procedure, the veterinarians took the opportunity to give her an examination — a difficult feat to manage when a beast weighing almost two tons is awake and less than cooperative. They trimmed Nola’s hooves, checked her eyes and ears, and monitored her vital signs.

Then they removed the horn. Rhino horns are made mostly of keratin, the same material as human fingernails, and sawing one off is a painless exercise. It is also temporary: Nola’s horn would eventually grow back.

Meanwhile, once the horn was cut off, Angie and Nola mated several times, although Nola has yet to become pregnant. The veterinarians at the San Diego Wild Animal Park continue to observe the rhinos’ behavior carefully, knowing that a baby rhino would be a big step towards ensuring the survival of this dwindling species. And every day, the veterinarians remain ready for animal medical emergencies, aware that the lives of these creatures are in their hands.