Топик: San-Diego Zoo

The history of the San Diego Zoo in recent years has been one of a new awareness of the role of zoos in our world. Under the able leadership of new directors and members of the board of trustees, the Zoo has become increasingly concerned with captive breeding and the conservation of wildlife. Consequently, a number of conservation projects have been established, both at the Zoo and Wild Animal Park as well as elsewhere around the world. The first international conference on the role of zoos in conservation was hosted by the San Diego Zoo in 1966, during the celebration of the Zoo's 50th birthday. In addition, the Zoological Society presented its first conservation awards that year.

Perhaps the most outstanding of the Zoo's conserva­tion projects has been the Center for Reproduction of Endangered Species (CRES). Launched in 1975 as an intensive research effort to improve the health and breeding success of exotic animals, CRES is dedicated to its primary goal of helping endangered species of animals reproduce and survive, both in captivity and in the wild.

Some of the achievements CRES is most proud of have included gratifying reproductive successes with cheetahs, Indian and southern white rhinoceroses, and Przewalski's wild horses.

THE ANIMALS OF EURASIA

Eurasia is the largest land mass on earth, stretching halfway around the globe from the British Isles to the Pacific Ocean, and from the Bering Sea south to the tip of Malaysia, an area of 54 million sq km (21 million:sq -л»ХА few of its animal species, especially those in the north, are closely related to, and in some instances are the same as, those of North America.

Relatively recently, as earth time is measured, Eurasia was linked to America by a land bridge which spanned what is now the Bering Straits. This causeway existed for thousands of years during the Ice Ages, when much of the earth's water was locked up in glaciers, thus lowering sea level. Animals crossed back and forth between the two continents on the land bridge, and the first human settlers in America prob­ably arrived via this route.

About ten thousand years ago, the latest in a series of ice ages came to an end. The ice melted; the seas rose, and the Bering land bridge was submerged. An­imal species which had wandered west into Eurasia or east to America were isolated from their native home­lands. But because ten thousand years is a mere eye wink in evolutionary timekeeping, very few changes have had time to take place in these exiles. For exam­ple, the largest member of the deer family lives in the taiga of both Eurasia and America. In Eurasia it is called an elk, in America, a moose. But it is one and the same animal. This is also true of another deer, the caribou, or reindeer. The former is a wild animal of America; the latter has been domesticated for cen­turies by the Lapps of northern Europe.

The Bering land bridge was probably responsible for the survival of at least one species — the horse. This animal originated in the western hemisphere, where it developed from a tiny, three-toed creature, to the form very much like the one we know today. During the Ice Ages, it migrated across the land bridge into Asia, where it thrived. In America the horse be­came extinct and didn't reappear here until the Spaniards brought it back as a domesticated animal in the 16th century.

The Spanish horses, as are all domestic breeds, were descendants of the wild horses which migrated from America. That original breed still exists. It is called Przewalski's horse, named for the naturalist who first brought specimens to Europe from the grasslands of Mongolia. This is the only true wild horse left in the world. All other so-called "wild" horses are feral ani­mals, that is, horses descended from domestic animals which escaped from or were released by their owners. Przewalski's horses once existed in large herds, but human intrusion into their habitat pushed them farther and farther back into a harsh environment where even these tough animals could not survive.

They were last seen in the wilderness in 1967. Fortu­nately breeding groups existed in zoos and reserves. Captive propagation brought the population up to about 700 by 1985, and four dozen Przewalski's horses have been born at the San Diego Zoo and the San Diego Wild Animal Park. Several of the Zoological So­ciety's Przewalski's horses are on breeding loans to other zoos.

The Eurasian bison, called a wisent, is closely related to the American bison. Although never so numerous as the American member of the species, wisent used to roam the forests which covered western Europe. Cen­turies of cutting destroyed all but a small remnant of these forests and came within 17 animals of exter­minating the wisent. A captive breeding program saved them and today a few hundred live in the Bialowieza Forest in eastern Poland. The San Diego Zoo has produced 25 calves.

If the felling of Europe's forests meant the destruc­tion of many wild animal species, it worked to the advantage of others. Deer, for instance, have thrived and live from the British Isles eastward. Red, roe and fallow deer live in western Europe, sika deer in Japan. Pere David's deer, formerly a native of marshy areas in central China, is extinct in the wild. It exists only in zoos and reserves.

The hedgerows of western Europe house many small animal species. There are foxes, rabbits, hares, badgers, ferrets, squirrels and birds. These and other animals have adapted to life in a human-dominated environment. Starlings and sparrows, for example, do so well that they are considered "pest" birds. Until recently, one of Europe's largest birds, the white stork, even nested in the smaller towns and villages. The bird was considered a symbol of good luck, and home-owners built platforms on rooftops for its nests. This practice is no longer common and the stork avoids the towns.

The most regal of Eurasia's raptors is the golden eagle, and the bird has figured in history for centuries. Its image was carried by Roman legions as they con­quered much of the continent. During the Middle Ages, lesser members of royalty were free to use other raptors for falconry, but the eagle was reserved for the king. Today, in more remote parts of Asia, the golden eagle is used to hunt wild goats, gazelles, foxes, and wolves. The bird occurs in the United States, where it is under federal protection. It can be seen in San Diego's back country and often is observed soaring over the San Diego Wild Animal Park.

Several other northern Eurasia predators are found in North America — falcons, hawks and owls; mam­mals including wolves, wolverines and foxes. a However, two mammalian predators are unique to I the Old World — leopards and tigers. Leopards range i from northern Asia into Africa; tigers live only in Asia I from Manchuria southward into India and Malaysia. There are five races of this great cat; all of them are endangered. The Zoo enjoys considerable success breeding and raising Siberian tigers, of which the total world population is only about 750 individuals. More than two dozen cubs have been born and raised at the Zoo.

South of the taiga, Eurasian biomes become less clearly defined. Much of the area is flat and treeless. In the west, where rainfall is adequate, grass grows thickly. But deep in the continent's interior, the land becomes a desert. Here, thousands of miles from the moderating effects of the ocean, temperatures can climb well above 38°C (100°F) in summer, and plum­met far below freezing in winter.

Animals must make drastic adjustments to these climatic extremes. One of the most common is migra­tion. Herders move their domestic herds and flocks, following the seasons, and many of the wild grazers also make similar journeys, with predators following along.

The animals which are permanent residents have adapted to the heat, cold and aridity of this area. The saiga, an antelope-like animal, has nostrils pointing downward to help keep out dust. Inside each of its nostrils the saiga has a sac which is believed to warm and moisten the air.

The Bactrian camel of Mongolia and China has adapted to its environment by growing a thick, shaggy, winter coat; broad, split hooves to keep from sinking into the sand; and two humps for storing fat when foraging is poor.

Several species of wild asses are native to the inte­rior of central Asia. Among these are the Mongolian kulan and Iranian onager. Asses are smaller than true horses and characterized by long ears, deep-set eyes coarse, wiry manes, small feet and tails tipped with long hairs. They can survive longer without water than other members of the horse family and are able to get along on a small amount of food. Because of their sure-footedness and endurance they are valuable beasts of burden and have been domesticated for centuries.

The Eurasian grassland is home to the heaviest of all flying birds, the 20 kg (45 lb) great bustard. And the world's smallest crane, the demoiselle which stands just 1 m (39 in) tall, breeds on grasslands from south­eastern Europe into central Asia.

Several species of wild sheep and goats live on the grasslands and adjacent mountains. Markhors and turs, both goats, range from Spain to India and northward into Mongolia and Siberia. The tahr, a goatlike animal, is found in the high Himalayas. Goats differ from sheep in that they have beards, feet with scent glands, convex foreheads, and a definite odor among the males.

Some of the world's most unusual mammals live in the mountains which separate central Asia from India. One of the best known is the giant panda, once considered a member of the raccoon family and now thought to be related to bears. This animal lives on a diet consisting mainly of bamboo shoots. For un­known reasons the bamboo is dying, which threatens the pandas' future. The Chinese government has commissioned a team of biologists to study the situa­tion. Although giant pandas have rarely reproduced in western zoos, a number of babies have been born in the Beijing zoo through natural conception, and artifi­cial insemination has recently been successful.

The giant panda shares its bamboo forest with the lesser panda. This animal looks like a raccoon but is related to the giant panda.

Central Asia is isolated from India and Burma by the Himalaya mountain range, the highest mountains on earth. The area is so remote that little is known about the behavior of many of its animals. It is the home of a collie-sized gazelle, several species of wild sheep, and a member of the cow family, the yak. The yak is also domesticated and has been a beast of burden and supplier of milk, wool and fuel for many centuries.

One of the most beautiful of all Himalayan animals is the snow leopard, or ounce. Its fur is in great demand and poaching has placed it in grave danger of extinction.

The snow leopard's main prey is the bharal, or blue sheep, which lives in the Himalayas and other high mountains in eastern Asia.

As one moves south from the high country, the character of the land and its animals change. Rugged mountains give way to forested foothills. This country is the northern edge of the sloth bear's range which also includes other parts of India and Sri Lanka (Ceylon). Termites are a part of the sloth bear's diet, and it sucks them in by a "vacuuming" process. The bear rips open the termites' nest with its claws, then blows away the dirt and dust, and starts sucking. Its lips protrude; its nostrils close to keep out dirt.

Beyond the foothills, seasonal forests give way to semi-arid plains and desert in India. Axis deer, nilgai (India's largest antelope) and blackbuck live here. In the Gir Forest is the last remnant population of the lions which once roamed from the Atlantic through the Near East and into Asia. But lions have been gone from most of this range for many centuries and exist today only in a protected reserve in the tiny Gir Forest in western India, where a few hundred individuals survive.