Реферат: Mammals

Like many wild dogs, the coyote is usually active at night, when it can hunt safely. You can often see a coyote in the early evening and morning, as it goes to and from its nighttime activities.

Coyotes can run as fast as 40 miles per hour, and at slightly slower speeds, they can run for miles. If a coyote can stay close to its prey, it has a good chance of getting a meal.

DHOLE

In hunting style, the dhole is like the hyena. It hunts in a pack with other dholes, whining, barking and whistling as they go. Whistling usually means that the hunt is unsuccessful, and the pack should reassemble for another try.

It is almost impossible for a single dhole to kill a deer, but five to twelve dholes can manage it together. After the kill, dholes compete for the morsels by eating very fast. A dhole can chew up almost nine pounds of meat in an hour.

Strong, wise, brave -- all these words describe the gray wolf. But another word needs to be added to the list: endangered.

Two hundred years ago, the gray wolf roamed throughout North America. But many of them were shot by European settlers and pioneers, who were busy cutting down the wolves' forest home for houses and towns. Those wolves that remained found fewer deer, moose and beaver to eat.

Today, the gray wolf continues to feel the impact of an expanding human population. That, and the popular belief that wolves shouldn't live near humans, continues to threaten their presence on our planet.

GRAY WOLF

Did you know that the gray wolf is the largest member of the dog family? Apart from man, it once was the most widespread mammal outside the tropics. As humans move into its habitat, the wolf had to move out.

Did you know that after humans, wolves may be the most adaptable creatures of all? They're able to live in a wider variety of climates and habitats than most other animals and can survive on many different kinds of food.

BEST LEFT UNPROVOKED

Wolves prey on many species in the north -- musk ox, caribou, moose, deer, hares and even rodents. These carnivores are among the most maligned of all animals, victims of false myths and legends and systematic programs of extinction. They are accused of attacking humans and destroying entire herds of domestic animals. But their depredations of livestock are less severe than often claimed. And unprovoked attacks by healthy wolves in North America on humans are unknown. Those recorded from Europe's Middle Ages are thought to have been by rabid animals or hybrids.

The world will be a far lonelier place if the last wolf dies. As biologist Ernest P. Walker wrote in his book, MAMMALS OF THE WORLD, "The howl of the wolf and coyote, which to some people is of more enduring significance than superhighways and skyscrapers, should always remain a part of our heritage."

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PRIMATS

APES: FUTURE

The future of apes is up to us. All of the great apes are already on the endangered species list, and all of the lesser apes are as well. Scientists who have studied them agree that all great apes will soon die out in the wild unless steps are taken now to protect them.

Gorillas and orangutans appear to have no natural enemies, and chimpanzees have very few. Gibbons, because they move so fast and live so high up in the trees, are safe from any animal. Nothing could threaten any of the apes with extinction until man started hunting them, capturing them, and destroying the wild lands in which they live.

Today, hunting of apes is against the law everywhere, and there are strict regulations controlling the capture of wild apes. But illegal hunting and trapping continues. And the greatest threat of all -- the destruction of wild lands -- grows greater every day. Tropical forests are being cut down faster today than ever before ... at the rate of one acre every second, according to a recent report. At this incredible pace, the homes of many wild creatures -- including apes -- are simply disappearing.

Most endangered of the apes are the mountain gorillas. Today, there are less than 500 in Central Africa.

And the other apes are not much better off. Nobody is really sure how many pygmy chimpanzees or bonobos survive in the jungles south of the Congo River -- but it is probably less than 10,000. There are fewer than 5,000 orangutans still alive in scattered areas of Borneo and Sumatra. And the numbers of lowland gorillas and chimpanzees are declining rapidly.

Fortunately, there are people who are trying to save the magnificent apes. In Central Africa, governments are working to protect the last remaining homes of mountain gorillas. They have even organized guards that patrol the borders of gorilla preserves to keep the gorillas safe from hunters. The World Wildlife Fund and other groups are raising money to buy land and make sure that it will never be taken away from gorillas, chimpanzees, orangutans, and gibbons. And scientists everywhere are studying the apes to find new ways to help them.

BONOBO OR PYGMY CHIMPANZEE

Biologists who have studied the behavior of these animals say they are the smarter of two species of chimpanzees. Their hair is parted at the middle and wisps out to the sides of the head, giving them an obvious physical distinction from the common chimpanzee.

Both species of chimps are intelligent. They belong to the select animals that make and use tools. You might see a chimp defend himself with a tree branch, or take a twig and turn it into a useful devise for gathering or eating foods. Chimps also communicate with many gestures and vocalizations.

People may feel especially drawn to chimps because of some similar behaviors. Young chimps laugh when they're tickled. Bonobos quarrel over food, but hug and kiss to make up.

BONOBO: WORKSHOP IN CONSERVATION

The bonobo or pygmy chimpanzee, is one of only four living species of great apes. The other three species, the gorilla, orangutan, and common chimpanzee, have received far greater attention until now. Not even recognized as a separate species until 1929, the bonobo still remains much of a mystery in its native habitat, the central rain forests of Zaire. Often confused with the common chimpanzee, the bonobo is only slightly smaller but has a more graceful, slender body; the head is smaller but the legs are longer than those of common chimps. The most outstanding physical difference is the bonobo's hairstyle, an attractive coiffure of long black hairs neatly parted down the middle. To the experienced eye, the difference between the chimpanzee and the bonobo is as great as the difference between a leopard and a cheetah.

The bonobo is as rare in zoos (there are less than 80 in captivity worldwide) as it is in the wild (estimates range from 5,000 to 20,000). In 1989, the entire San Diego Zoo group of 11 animals was relocated to the Wild Animal Park.

No effective conservation plan for the bonobo could be developed without firsthand knowledge of the only country that is home to this critically endangered ape. International conservation projects are as much a people issue as an animal issue; therefore, the needs of the local Zairian people must be taken into account. Political, cultural, and economic problems are just as important to consider as the biological needs of the species we are attempting to save. For these reasons, the San Diego Bonobo Workshop continually emphasizes the need for an international cooperative effort with the people and government of Zaire.

In light of the increasing awareness of the need to preserve the world's biodiversity, it is quite surprising how little attention Zaire has received. The extent and variety of the biological resources in Zaire's forest ecosystems is matched by few other tropical countries. After Brazil, Zaire has the second largest tropical forest in the world. Despite this fact, Zaire is among the last of the countries in the tropical forest belt without a comprehensive program to protect its tropical forest. Programs like the one developed at the San Diego Bonobo Workshop will be instrumental in obtaining funds from organizations like the World Bank to protect the bonobo and its forest habitat.

THE GORILLA SUBSPECIES

Three subspecies of gorillas are currently recognized. Almost all zoo gorillas are western lowland gorilla (Gorilla gorilla) native to west African nations such as Cameroon, the Central African Republic, Gabon, Nigeria, and Rio Muni. The total population of western lowland gorillas is estimated to be between 30,000 to 50,000 individuals, and they are classified as threatened by the IUCN (International Union for Conservation of Nature and Natural Resources). Studying these gorillas in the wild is extremely difficult, because their preferred habitat is dense jungle.

A very few eastern lowland gorillas (Gorilla gorilla graueri) native to eastern Zaire, live in zoos. Mbongo and Ngagi, the two "mountain gorillas" who lived at the San Diego Zoo in the 1930s and 1940s, would now be classified as eastern lowland gorillas. These gorillas are considered the largest subspecies on average, and generally have blacker hair than western lowland gorillas. They number approximately 3,000 to 4,000 and are classified as endangered.

No mountain gorillas (Gorilla gorilla beringei) exist in captivity, but these are the most-studied gorillas in the wild. They live in the mountainous border regions of Rwanda, Uganda, and Zaire. Only about 600 individuals exist, in two separate populations, and they are classified as endangered. Mountain gorillas are distinguished physically by their large size and extra-long, silky black hair. A number of skeletal differences exist between the three subspecies as well.

It would be interesting to see if DNA sequence comparisons could help us understand the phylogenetic (evolution of a genetically related group as distinguished from the development of the individual organism) relationships of the gorilla subspecies. This could help anthropologists understand the mechanisms and rates of primate evolution. It could also be important if gorilla populations ever become so critically depleted that interbreeding of different subspecies were contemplated. At CRES, we are comparing DNA sequences from gorillas of all three subspecies. Only a few gorillas have been tested so far, but to date it appears that the relationships between the subspecies generally follows the geographic location of populations.