4 . Amur tigers, also known as Siberian tigers, are interesting animals. They are the biggest cats in the world. A full-grown Amur tiger can weigh over 600 pounds. Unlike lions that live in groups, tigers are solitary animals. Tigers also have very good eyesight and hearing. Its eyesight is six times better than a human’s.

Amur tigers live in the forests located in the Russian Far East and northeastern China. They have a thick yellow fur coat with black stripes(条纹). Their stripes are like human fingerprints. Every tiger has a different and unique stripe pattern. Tigers use their striped coat to hide themselves from the animals they hunt. Their thick fur and a thick layer of fat keep them warm during the long, cold winters in the forest.

As powerful and quiet hunters, Amur tigers usually hunt at night. Sometimes these tigers travel hundreds of miles looking for food. They hunt deer and wild boar(野猪) that live in the forest. They also hunt smaller types of bears. A hungry Amur tiger can eat more than 50 pounds in one night.

Today, Amur tigers are an endangered species. People illegally hunt Amur tigers. Amur tigers are also still in danger because the forests they live in are being destroyed. Illegal logging(砍伐) and new roads destroy their forest homes. It makes it hard for the tigers to find food. It also makes it difficult for the tigers to travel for long distances. They almost disappeared forever at the beginning of the 20th century—They were hunted until only 40 tigers remained in the wild.

Countries like Russia then began to protect these big cats. They made it illegal to hunt them and tried to protect their forest habitat. After these changes, the number of Amur tigers living in the wild increased. Scientists believe there are about 540 Amur tigers living in the wild today.

6 . Some animals enjoy playing just like humans do although researchers used to think that applied mostly to birds and mammals. An animal plays when it does something that doesn’t seem to be constructive to its survival so it’s not about food or shelter, for instance. The behavior is also often done again and again.

However, scientists have now conducted experiments that seems to prove bees play too. As far as the experts know, bees are the only insect to do so.

Researchers from Queen Mary University in London earned out an experiment in which bumble bees were taught to roll little balls with the aim of being rewarded with food. They then discovered the insects kept rolling balls even when they weren’t rewarded. They then did another experiment: a path was built from the beehive to a section containing food. Balls were placed on each side of the path leading to the food. The balls on one side were glued down and couldn’t move and the balls on the other side were free and capable of moving. The bees could stay on the path to get to their food, but they always went to the side of the moveable balls and rolled them along. One bee even rolled the balls 44 times in one day.

Researchers say the experiments may well show insects are more evolved than we think.

8 . Biologist Marc Bekoff studies dogs, wolves and coyotes.     1    . If they’re in the same pack, animal friends may sleep close to one another. They greet one another, travel together, share food and groom each other. Animal friends are nice to one another, and they even play together.    2    .

Playing together, for instance, helps animals bond and keeps them close to the group. “Coyote pups who don’t play together are more likely to go out on their own.    3    .” says Bekoff. “If an animal has a special friend, both friends benefit by having someone to watch out for them.”

    4    . When a young rhinoceros sets out on its own for the first time, it may look for an older travel friend, and this companion helps to find food and water and avoid predators. Young male elephants hang out together when they leave their mothers’ herds, and young dolphins do, too. Pairs of bottlenose dolphins sometimes form strong bonds and pal around together for years. Among chimpanzee groups, some pair up to groom each other, hunt together, share food and defend each other from danger.

Why do animals have friends? “Mainly because in the long run they benefit from friendships,” scientist Franz de Waal says. “It is all give and take.    5    .”

9 . As the air cools and sunlight decreases each fall, thousands of western monarch butterflies (帝王蝶) return to California to spend winter. One of the best places to watch the colorful scene is Pismo Beach.

From now through February, over 10, 000 will fly to trees at Pismo Beach Monarch Butterfly Grove, one of five locations in the state to host so many of the colorful creatures. Just like tourists, the western monarchs prefer the sunny and warm conditions of the beachside state park.

The migration peaks in November, when the last of the western monarchs settle into the trees at Pismo Beach Monarch Butterfly Grove. Some have flown over 1, 000 miles from as far away as Canada to escape winter's low temperatures. The butterflies gather on tree branches, where they mostly remain sitting, until sunlight bathes the trees and the western monarchs begin to beat their wings. Activity reaches its peak in February.

While this annual sight is wonderful, it pales in comparison to what used to be. Millions of western monarch butterflies used to spend winter in California and Mexico only a few decades ago. Climate change, loss of natural habitat and harmful chemicals are just a few of the environmental threats that have caused a more than 99% decrease in populations since the 1980s, according to a research.

“In monarchs’ overwintering trees, there were once so many butterflies that the sound of their wings was described as a summer rain,” states the Center for Biological Diversity. “Early newspaper descriptions described branches breaking under the weight of so many butterflies.”

Conservation efforts are underway in several states, including California, to help restore populations of monarch and western monarch butterflies. However, it is unknown how successful these attempts will be. Scientists are concerned about the possibility of a complete collapse of the species since numbers have dropped so dramatically in the last few years.

10 . A mobile(移动的)hospital for treating injured wildlife has just begun a journey to its new base in Byron Bay, on Australia's east coast.

Byron Bay Wildlife Hospital founder and Professor Stephen Van Mil said that Australia's annual disastrous(灾难性的)wildfire season could _______ the animals’variety. Seeing the _______ koalas sitting in baskets waiting for care was _______ .

By now, several charities, and help from animal protection groups have turned the mobile hospital into a _______ .

It is housed in a 16-meter _______ that was partially helped by the World Wildlife Fund, which was _______ by a group of international environmentalists to raise money _______ global efforts. Inside, the truck comes with all the _______ an animal hospital needs, including X-ray machines, ultrasound(超声)facilities, and special cages. To make sure that the mobile hospital can help even in the most _______ conditions, it is 100 per cent self-sufficient(自给自足). It uses solar energy to produce electricity and has its own water collection and management systems so that it can arrive anywhere and be set up and ready to go in ________ .

“Being able to work in a mobile hospital ________ that I can actually help these animals quickly. I can get there and I can concentrate on the ________ that they need," said wildlife specialist Dr. Bree Talbot, who will be aboard the mobile hospital along with a small team of volunteers.

Australia can be a ________ place to live for wild animals. Experts determined that up to a billion wild creatures were ________ by the 2020 wildfires alone. Offering help to these animals in times of crisis is a major challenge, and this amazing mobile hospital seems to have arrived at the ________ time.