科普英语的内容?

暗银河系的发现及其科学意义

In addition to conventional galaxies, the universe contains very dim galaxies that until recently went unnoticed by astronomers. Possibly as numerous as conventional galaxies, these galaxies have the same general shape and even the same approximate number of stars as a common type of conventional galaxy, the spiral, but tend to be much larger. Because these galaxies ’mass is spread out over larger areas, they have far fewer stars per unit volume than do conventional galaxies. Apparently these low-surface-brightness galaxies, as they are called, take much longer than conventional galaxies to condense their primordial gas and convert it to stars—that is, they evolve much more slowly.

These galaxies may constitute an answer to the long-standing puzzle of the missing

baryonic mass in the universe. Baryons—subatomic particles亚原子粒子 that are generally protons or neutrons—are the source of stellar, and therefore galactic, luminosity, and so their numbers can be estimated based on how luminous galaxies are. However, the amount of helium in the universe, as measured by spectroscopy光谱学, suggests that there are far more baryons in the universe than estimates based on galactic luminosity indicate. Astronomers have long speculated that the missing baryonic mass might eventually

be discovered in intergalactic space星系际的空间 or as some large population of galaxies that are difficult to detect.

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另类海豹哺乳方式与众不同

Until recently, zoologists believed that all species of phocids (true seals), a pinnipped family, use a different maternal strategy than do otariids (fur seals and

sea lions), another pinniped family. Mother otariids use a foraging strategy. They acquire moderate energy stores in the form of blubber before arriving at breeding sites and then fast for 5 to 11 days after birth. Throughout the rest of the lactation (milk production) period, which lasts from 4 months to 3 years depending on the species, mother otariids alternately forage at sea, where they replenish their fat stores, and nurse their young at breeding sites. Zoologists had assumed that females of all phocids species, by contrast,

use a fasting strategy in which mother phocids, having accumulated large energy

stores before they arrive at breeding sites, fast throughout the entire lactation period, which lasts from 4 to 50 days depending on the species. However, recent studies on

harbor seals, a phocids species, found that lactating females commenced foraging

approximately 6 days after giving birth and on average made 7 foraging trips during the remainder of their 24-day lactation period.

The maternal strategy evolved by harbor seals may have to do with their small size and the large proportion of their fat stores depleted in lactation. Harbor seals are small compared with other phocids species such as grey seals, all of which are known to fast for the entire lactation period. Studies show that mother seals of these species use respectively 84 percent, 58 percent, and 33 percent of their fat stores during lactation. By comparison, harbor seals use 80 percent of their fat stores in just the first 19 days of lactation, even though they occasionally feed during this period. Since such a large proportion of their fat stores is exhausted despite feeding, mother harbor seals clearly cannot support all of lactation using only energy stored before giving birth. Though smaller

than many other phocids, harbor seals are similar in size to most otariids. In addition,

there is already some evidence suggesting that the ringed seal, a phocids species that

is similar in size to the harbor seal, may also use a maternal foraging strategy.

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pheromones是什么东东，是不是该划为odorant

There is no consensus among researchers regarding what qualifies a substance as a pheromone. While most agree on a basic definition of pheromones as chemicals released by one individual of a species which, when detected by another individual of the same species, elicit a specific behavioral or physiological response, some researchers also specify that the response to pheromones must be unconscious. In addition, the distinction

between pheromones and odorants—chemicals that are consciously detected as odors—can be blurry, and some researchers classify pheromones as atype of odorant. Evidence that pheromone responses may not involve conscious odor perception comes from the finding that in many species, pheromones are processed by the vomeronasal (or accessory olfactory) system, which uses a special structure in the nose, the vomeronasal organ (VNO),to receive chemical signals. The neural connections between the VNO and the brain are separate from those of the main olfactory system, whose processing of

odorants triggers sensations of smell. But while the VNO does process many animal

pheromone signals, not all animal pheromones work through the VNO. Conversely,

not all chemical signals transmitted via the VNO quality as pheromones. For example,

garter snakes detect a chemical signal from earthworms—one of their favorite foods—via

the VNO, and they use this signal to track their prey.

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关于一篇 Animais 的英语作文

帮你找了一篇Animal的文章，下面还有一篇lion的文章：

Animal

Animals live everywhere. They roam the land. They burrow in the ground. They swim in the sea. They fly through the air. They creep, they leap, they soar, and they dive. A very few—including corals and barnacles—stay in one place.

Animals come in all sizes. The biggest animals are whales, which can be 100 feet (30 meters) long. The smallest animals can only be seen through a microscope.

Zoologists (scientists who study animals) have found more than 2 million species (kinds) of animals. They think they have discovered only a small portion of all animals on Earth.

Several things make animals different from other living things. Unlike plants, animals cannot make their own food. Animals eat other living things—plants and other animals—to get energy. Animal bodies are made up of more than one cell, unlike bacteria and other life forms with only one cell. Cells are the building blocks of living things. Animals also have senses, such as eyes or ears, that tell them what is going on around them.

WHAT KINDS OF ANIMALS ARE THERE?

Zoologists divide animals into about 30 groups. First, they divide them by whether they have a backbone. Animals that have a backbone are called vertebrates. Animals that do not have a backbone are called invertebrates.

The biggest and best-known animals are vertebrates. Mammals, birds, reptiles, amphibians, and fish are vertebrates. You are a vertebrate. Your backbone is also called your spine. There are about 40,000 species of vertebrates.

There are far more species of invertebrates. Even though you can probably think of many vertebrates, the many kinds of invertebrates greatly outnumber vertebrates. Almost all invertebrates are small animals. Insects, spiders, mollusks, and worms are all invertebrates. The biggest invertebrate is the giant squid. It can be up to 60 feet (18 meters) long.

COLD-BLOODED AND WARM-BLOODED ANIMALS

Zoologists divide vertebrates into two types, cold-blooded and warm-blooded animals. The body of a cold-blooded animal is the same temperature as the air or water around it. A cold-blooded animal has to stay in the sun to get warm. It must find shade to cool off. Reptiles, amphibians, and fish are cold-blooded.

The body of a warm-blooded animal stays about the same temperature all the time. Warm-blooded animals use food energy to stay warm. Some warm-blooded animals can sweat to cool off. Birds and mammals are warm-blooded.

You are warm-blooded. The normal temperature of your body stays at about 98.6° Fahrenheit (37.0° Celsius). When it is hot outside, you feel hot. You might sweat or look for an air-conditioned place. But your body temperature does not change. When it is cold outside, you feel cold. You might put on a coat or go indoors. But your body temperature does not change much.

PLANT EATERS AND MEAT EATERS

All animals eat plants, other animals, or the remains of dead animals. Animals that only eat plants are called herbivores. They eat seeds, nuts, grasses, stems, or flowers. Some mammals, such as cows, are plant eaters. Some insects, such as termites, only eat plants. Bees, moths, and butterflies suck nectar from flowers.

Animals that only eat meat are called carnivores. The meat can be from other living animals or animals that have died. Many meat eaters hunt the animals that they eat. Sharks go after smaller fish. Lions and wolves hunt deer and other mammals. Owls swoop down on rabbits, squirrels, rats, and mice. Some frogs and lizards zap insects with their sticky tongues. Hyenas and vultures mainly eat animals that are already dead.

Animals that commonly eat both animals and plants are called omnivores. Bears and opossums are omnivores. Humans are omnivores. They eat fruit, vegetables, fish, chicken, and steak.

HOW ANIMALS BREATHE

All animals must breathe oxygen to stay alive. They must breathe out a waste gas called carbon dioxide.

Some animals breathe through lungs. Lungs take oxygen out of air. Cattle, dogs, cats, whales, people, and other mammals breathe through lungs. Birds and reptiles also breathe air through lungs.

Lungs cannot take air from water. Seals, whales, dolphins, and other mammals that live in water breathe through lungs. They can stay underwater a long time because they can hold their breath for a long time.

Sharks and other fish breathe through gills. Gills take oxygen out of water. Snails, slugs, clams, squids, octopuses, and other mollusks breathe through gills. Crabs, crayfishes, lobsters, and shrimp have gills. Gills cannot take oxygen out of air.

Some animals breathe through their skin. Insects have small holes in their bodies called spiracles. Air comes in through the holes. Oxygen from the air goes through tubes to all parts of an insect’s body.

Amphibians, animals that live on land and in water, can also breathe through their skin. Amphibians also may have lungs or gills or both.

Lion

What if you could yell to a friend who lived several miles away—and your friend could hear you? That is how loud a lion can roar! No wonder this mighty animal is called the king of beasts.

Lions are big cats. Along with tigers, lions are the world’s biggest and strongest cats. There are two kinds of lions, African and Asian lions. Lions live on grassy plains, savannas, and dry woodlands in Africa and India. They do not like to live in jungles and thick forests.

MASSIVE BODIES

Lions have huge shoulders, strong front legs, and powerful jaws. Their paws have long, sharp claws. To keep its claws sharp, a lion draws them in when not in use.

Male lions are large and powerful. They weigh from 330 to 550 pounds (150 to 250 kilograms) and stand about 4 feet (about 1.2 meters) tall at the shoulder. Female lions are smaller than males.

FUR AND MANE

The fur of grown-up lions can be light tan to reddish-brown. Lions have darker fur on the backs of their ears. Their tails have a tuft of darker fur on the end.

Male lions grow a kind of fur collar called a mane. The mane grows around their head, neck, and shoulders. The mane becomes darker and fuller as the lion gets older. It makes a lion appear larger and fiercer to opponents.

Cubs, or baby lions, have fur dotted with many spots. The spots help them hide from enemies in brush and clumps of grass. The spots fade as the cubs grow up.

WHAT IS A PRIDE?

Lions live in groups called prides. There are as many as 35 males, females, and cubs in a pride. All the females in a pride are related. The females in the pride hunt together and care for cubs together.

The males in a pride are not always related. Males join a female pride to mate and produce cubs. Males do not help care for cubs. Males patrol their territory. They try to keep rival males away from their pride.

When female cubs grow up they stay with the pride. Males must leave the pride.

HUNTING AND EATING

Female lions do most of the hunting. Lions like to hunt at night. They hunt alone or in groups. A lion alone often hunts smaller prey such as hares or warthogs. The lion slowly and silently stalks the animal. If the prey sees the lion and runs, the lion usually gives up. When the lion gets close enough, it suddenly runs for the prey. It grabs the animal with its teeth and claws, pulls it to the ground, and kills it.

Groups of lions hunt large prey, such as buffalo, zebras, and even giraffes. A group of lions may surround an animal to trap it. Some lions may drive the animal toward waiting lions. Two or more lions grab and bring down the animal. Lions also steal prey killed by other animals, such as hyenas.

The pride eats together. Males eat first. Then the females eat. Cubs eat last.

A HARD LIFE

Lions do not have an easy life in the wild. They starve when they cannot find food. They get injured or killed while hunting or fighting with each other. They suffer from diseases.

Males have bloody fights. Younger males challenge older males for leadership of a pride. Sometimes they drive the older males away.

Females fight with the new males. The new males try to kill cubs that were fathered by the other males. Females are too small to fight male lions one on one. But the pride females may join together to save their cubs.

Male lions only live about 10 years in the wild. Females live a little longer. In zoos where they are cared for and cannot fight, lions may live as long as 25 years.

THREATS TO LIONS

Lions once roamed all over Europe, Africa, the Middle East, and Asia. People have hunted and killed lions since ancient times. They have also hunted the animals lions need for food. In many places, people have destroyed the areas where lions lived by building towns, roads, and farms.

There are about 100,000 lions left in the world. Only a few hundred Asian lions live in India. Most lions live on game reserves in Africa. Thousands of lions also live in zoos and circuses around the world.

袋鼠的英文介绍还要翻译

Kangaroos originated in the Australian continent and parts of Papua New Guinea. Among them, some species unique to Australia. All Australian kangaroo, zoo and wild, except in zoos, are living in the wild. Different types of kangaroos in Australia in a variety of natural life, from the cool climate of the rainforest and the desert plains to tropical areas.

Kangaroo is a herbivore, eating a variety of plants, fungi and some food. Most of their activities at night, but also some activities in the early morning or evening. Different types of kangaroos in a variety of natural life. For example, Lloyd Kangaroo Podolski will make their own nest and the tree kangaroos live in the bush. Large species like the tree kangaroo, the rock cracks and holes as shelter.

All kangaroos, no matter how much volume, there is one thing in common: with long hind legs strong and powerful bond. Kangaroo on the ground most of life, from their strong hind legs jumping way can easily be distinguished from other animals to. Used in the process of jumping kangaroo tail for balance when they move slowly, the tail may act as a fifth leg.

All female kangaroos have long ago opened bag of childcare and child rearing, there are four nipples pocket. “Young” or small kangaroo pockets in the dependent child up until they can survive in the outside world.

Kangaroo is Australia’s unique mammals, mainly located in the Australian continent on the forest and grassland. Kangaroo is a plant-eating animals, hiding in the woods during the day and at night to eat grass and leaves outside. The image of the kangaroo is unique: forelimb short toe fingers Elephant Man, strong hind legs, long thick tail, kangaroo tail is a powerful tool, and they who are able to provide support for the kangaroo, kangaroo running can also change the direction of running. Kangaroo tail tapered at the end, the muscles are very strong, up to 1 meter in length. Kangaroo is the most famous living in the grasslands of the Red Kangaroo is the largest category of Kangaroo, the strongest person. Gray kangaroo is jumping experts can jump great distances. Australian gold, about 47 kinds of kangaroo, the kangaroo in the body length 23-250 cm. Kangaroo is not due to fear, so zoologists kangaroo animals in the study encounter trouble when the relatively much smaller. Although kangaroos are not light weight, and sometimes up to 70 kilograms, but their run at an alarming rate, up to 48 kilometers per hour, and they jump up to the first 13 meters away.

Kangaroos originated in the Australian continent and parts of Papua New Guinea. Among them, some species unique to Australia. All Australian kangaroo, zoo and wild, except in zoos, are living in the wild. Different types of kangaroos in Australia in a variety of natural life, from the cool climate of the rainforest and the desert plains to tropical areas.

Kangaroo is a herbivore, eating a variety of plants, fungi and some food. Most of their activities at night, but also some activities in the early morning or evening. Different types of kangaroos in a variety of natural life. For example, Lloyd Kangaroo Podolski will make their own nest and the tree kangaroos live in the bush. Large species like the tree kangaroo, the rock cracks and holes as shelter.

All kangaroos, no matter how much volume, there is one thing in common: with long hind legs strong and powerful bond. Kangaroo on the ground most of life, from their strong hind legs jumping way can easily be distinguished from other animals to. Used in the process of jumping kangaroo tail for balance when they move slowly, the tail may act as a fifth leg.

All female kangaroos have long ago opened bag of childcare and child rearing, there are four nipples pocket. “Young” or small kangaroo pockets in the dependent child up until they can survive in the outside world.

Kangaroo plans often as Australia’s national identity, such as green kangaroo used to represent the Australian-made. Often appears kangaroo map the road in Australia, it is often near the Kangaroo said, especially pay attention to traffic at night.

Kangaroo is usually the main social, and sometimes up to hundreds. But there are also some lesser quality, such as kangaroos wallabies will be living alone.

Kangaroo will not walk, will jump, or in the front and back help before jumping off. Kangaroo is the night life of animals, usually in a few hours after the sun sets only to find out z food out in the sun back to the nest soon after.Kangaroo reproductive one or two each year, small kangaroo in both fertilized about 30-40 days of birth, very small, no vision, less hair, immediately after giving birth kept in the kangaroo mother care bags. 6-7 months until the beginning of a short period of time to leave the bags of life care. One year after the formal weaning can leave bags of conservation, it is still in the vicinity of the mother kangaroo, at any time for help and protection. Kangaroo mother can have a bag outside in a small kangaroo, a kangaroo in a small bag and a small kangaroo labor.

Run a small kangaroo from the ground near the green grass of the living grass and hay will be left to other animals. Individual types of kangaroo have teeth to eat the leaves or small tree.

The most famous is the red kangaroo kangaroo, the largest living in dry areas of Australia, the area’s annual average rainfall of 500 mm. As the kangaroo food containing large amounts of water, so he is not running water in the region survive. Red Kangaroo is actually only the public and the red kangaroo, kangaroo mother to a blue gray.

袋鼠原产于澳大利亚大陆和巴布亚新几内亚的部分地区。其中，有些种类为澳大利亚独有。所有澳大利亚袋鼠，动物园和野生动物园里的除外，都在野地里生活。不同种类的袋鼠在澳大利亚各种不同的自然环境中生活，从凉性气候的雨林和沙漠平原到热带地区。

袋鼠是食草动物，吃多种植物，有的还吃真菌类。它们大多在夜间活动，但也有些在清晨或傍晚活动。不同种类的袋鼠在各种不同的自然环境中生活。比如，波多罗伊德袋鼠会给自己做巢而树袋鼠则生活在树丛中。大种袋鼠喜欢以树、洞穴和岩石裂缝作为遮蔽物。

所有袋鼠，不管体积多大，有一个共同点：长着长脚的后腿强键而有力。大多数袋鼠在地面生活，从它们强健的后腿跳越的方式很容易便能将其与其他动物区分开来。袋鼠在跳跃过程中用尾巴进行平衡，当它们缓慢走动时，尾巴则可作为第五条腿。

所有雌性袋鼠都长有前开的育儿袋，育儿袋里有四个乳头。“幼崽”或小袋鼠就在育儿袋里被抚养长大，直到它们能在外部世界生存。

袋鼠是澳大利亚独有的哺乳动物，主要分布在澳大利亚大陆的森林中和草原上。袋鼠是草食动物，白天躲在树林中，晚上则到外面吃草和树叶。袋鼠的形象很独特：前肢短小，趾象人的手指，后腿强壮，尾巴粗而长，袋鼠的尾巴是一种强有力的工具，它们平时可以为袋鼠提供支架，也可以在袋鼠奔跑时改变奔跑的方向。袋鼠的尾巴在末端逐渐变细，肌肉非常强健，长度可达1米。最著名的袋鼠是生活在草原上的红大袋鼠，是袋鼠类中最大的、最强壮者。灰袋鼠是跳跃能手，能跳很远的距离。澳大利亚金约有47种袋鼠，这些袋鼠的体长在23-250厘米以上。由于袋鼠并不怕人，因此动物学家在研究袋鼠类动物时所遇到的麻烦就相对少得多。尽管袋鼠的体重不轻，有时甚至达到70公斤，但它们的奔跑速度惊人，时速可达48公里，而它们一次跳跃可达13米远。

袋鼠原产于澳大利亚大陆和巴布亚新几内亚的部分地区。其中，有些种类为澳大利亚独有。所有澳大利亚袋鼠，动物园和野生动物园里的除外，都在野地里生活。不同种类的袋鼠在澳大利亚各种不同的自然环境中生活，从凉性气候的雨林和沙漠平原到热带地区。

袋鼠是食草动物，吃多种植物，有的还吃真菌类。它们大多在夜间活动，但也有些在清晨或傍晚活动。不同种类的袋鼠在各种不同的自然环境中生活。比如，波多罗伊德袋鼠会给自己做巢而树袋鼠则生活在树丛中。大种袋鼠喜欢以树、洞穴和岩石裂缝作为遮蔽物。

所有袋鼠，不管体积多大，有一个共同点：长着长脚的后腿强键而有力。大多数袋鼠在地面生活，从它们强健的后腿跳越的方式很容易便能将其与其他动物区分开来。袋鼠在跳跃过程中用尾巴进行平衡，当它们缓慢走动时，尾巴则可作为第五条腿。

所有雌性袋鼠都长有前开的育儿袋，育儿袋里有四个乳头。“幼崽”或小袋鼠就在育儿袋里被抚养长大，直到它们能在外部世界生存。

袋鼠图常作为澳大利亚国家的标识，如绿色袋鼠用来代表澳大利亚制造。袋鼠图还经常出现在澳大利亚公路上，那是表示附近常有袋鼠出现，特别是夜间行车要注意。

袋鼠通常以群居为主，有时可多达上百只。但也有些较小品质的袋鼠如wallabies会单独生活。

袋鼠不会行走，只会跳跃，或在前脚和后腿的帮助下奔跳前行。袋鼠属夜间生活的动物，通常在太阳下山后几个小时才出来寻食，而在太阳出来后不久就回巢。

袋鼠每年生殖一至二次，小袋鼠在受精 30-40 天左右既出生，非常微小，无视力，少毛，生下后立即存放在袋鼠妈妈的保育袋内。直到 6-7 个月才开始短时间地离开保育袋学习生活。一年后才能正式断奶，离开保育袋，但仍活动在妈妈袋鼠附近，随时获取帮助和保护。袋鼠妈妈可同时拥有一在袋外的小袋鼠,一在袋内的小袋鼠和一待产的小袋鼠.

袋鼠以矮小润绿离地面近的小草为生,将长草与干草留给其它动物。个别种类的袋鼠也吃树叶或小树牙。

最著名的袋鼠是红袋鼠，其体型最大，生活在澳大利亚干燥地带，其地带的年平均降雨量在 500毫米以下。由于袋鼠的食物含大量水分，所以他在没有活水的地区也能生存。红袋鼠实际上只有公袋鼠是红色的，母袋鼠为灰蓝色。

]

我不知道你们现在5年级的水平（-，-） 你认为哪些你会 你就自己看吧

一篇150字左右的英语作文

Animal

Animals live everywhere. They roam the land. They burrow in the ground. They swim in the sea. They fly through the air. They creep, they leap, they soar, and they dive. A very few—including corals and barnacles—stay in one place.

Animals come in all sizes. The biggest animals are whales, which can be 100 feet (30 meters) long. The smallest animals can only be seen through a microscope.

Zoologists (scientists who study animals) have found more than 2 million species (kinds) of animals. They think they have discovered only a small portion of all animals on Earth.

Several things make animals different from other living things. Unlike plants, animals cannot make their own food. Animals eat other living things—plants and other animals—to get energy. Animal bodies are made up of more than one cell, unlike bacteria and other life forms with only one cell. Cells are the building blocks of living things. Animals also have senses, such as eyes or ears, that tell them what is going on around them.

WHAT KINDS OF ANIMALS ARE THERE?

Zoologists divide animals into about 30 groups. First, they divide them by whether they have a backbone. Animals that have a backbone are called vertebrates. Animals that do not have a backbone are called invertebrates.

The biggest and best-known animals are vertebrates. Mammals, birds, reptiles, amphibians, and fish are vertebrates. You are a vertebrate. Your backbone is also called your spine. There are about 40,000 species of vertebrates.

There are far more species of invertebrates. Even though you can probably think of many vertebrates, the many kinds of invertebrates greatly outnumber vertebrates. Almost all invertebrates are small animals. Insects, spiders, mollusks, and worms are all invertebrates. The biggest invertebrate is the giant squid. It can be up to 60 feet (18 meters) long.

COLD-BLOODED AND WARM-BLOODED ANIMALS

Zoologists divide vertebrates into two types, cold-blooded and warm-blooded animals. The body of a cold-blooded animal is the same temperature as the air or water around it. A cold-blooded animal has to stay in the sun to get warm. It must find shade to cool off. Reptiles, amphibians, and fish are cold-blooded.

The body of a warm-blooded animal stays about the same temperature all the time. Warm-blooded animals use food energy to stay warm. Some warm-blooded animals can sweat to cool off. Birds and mammals are warm-blooded.

You are warm-blooded. The normal temperature of your body stays at about 98.6° Fahrenheit (37.0° Celsius). When it is hot outside, you feel hot. You might sweat or look for an air-conditioned place. But your body temperature does not change. When it is cold outside, you feel cold. You might put on a coat or go indoors. But your body temperature does not change much.

PLANT EATERS AND MEAT EATERS

All animals eat plants, other animals, or the remains of dead animals. Animals that only eat plants are called herbivores. They eat seeds, nuts, grasses, stems, or flowers. Some mammals, such as cows, are plant eaters. Some insects, such as termites, only eat plants. Bees, moths, and butterflies suck nectar from flowers.

Animals that only eat meat are called carnivores. The meat can be from other living animals or animals that have died. Many meat eaters hunt the animals that they eat. Sharks go after smaller fish. Lions and wolves hunt deer and other mammals. Owls swoop down on rabbits, squirrels, rats, and mice. Some frogs and lizards zap insects with their sticky tongues. Hyenas and vultures mainly eat animals that are already dead.

Animals that commonly eat both animals and plants are called omnivores. Bears and opossums are omnivores. Humans are omnivores. They eat fruit, vegetables, fish, chicken, and steak.

HOW ANIMALS BREATHE

All animals must breathe oxygen to stay alive. They must breathe out a waste gas called carbon dioxide.

Some animals breathe through lungs. Lungs take oxygen out of air. Cattle, dogs, cats, whales, people, and other mammals breathe through lungs. Birds and reptiles also breathe air through lungs.

Lungs cannot take air from water. Seals, whales, dolphins, and other mammals that live in water breathe through lungs. They can stay underwater a long time because they can hold their breath for a long time.

Sharks and other fish breathe through gills. Gills take oxygen out of water. Snails, slugs, clams, squids, octopuses, and other mollusks breathe through gills. Crabs, crayfishes, lobsters, and shrimp have gills. Gills cannot take oxygen out of air.

Some animals breathe through their skin. Insects have small holes in their bodies called spiracles. Air comes in through the holes. Oxygen from the air goes through tubes to all parts of an insect’s body.

Amphibians, animals that live on land and in water, can also breathe through their skin. Amphibians also may have lungs or gills or both.

Lion

What if you could yell to a friend who lived several miles away—and your friend could hear you? That is how loud a lion can roar! No wonder this mighty animal is called the king of beasts.

Lions are big cats. Along with tigers, lions are the world’s biggest and strongest cats. There are two kinds of lions, African and Asian lions. Lions live on grassy plains, savannas, and dry woodlands in Africa and India. They do not like to live in jungles and thick forests.

MASSIVE BODIES

Lions have huge shoulders, strong front legs, and powerful jaws. Their paws have long, sharp claws. To keep its claws sharp, a lion draws them in when not in use.

Male lions are large and powerful. They weigh from 330 to 550 pounds (150 to 250 kilograms) and stand about 4 feet (about 1.2 meters) tall at the shoulder. Female lions are smaller than males.

FUR AND MANE

The fur of grown-up lions can be light tan to reddish-brown. Lions have darker fur on the backs of their ears. Their tails have a tuft of darker fur on the end.

Male lions grow a kind of fur collar called a mane. The mane grows around their head, neck, and shoulders. The mane becomes darker and fuller as the lion gets older. It makes a lion appear larger and fiercer to opponents.

Cubs, or baby lions, have fur dotted with many spots. The spots help them hide from enemies in brush and clumps of grass. The spots fade as the cubs grow up.

WHAT IS A PRIDE?

Lions live in groups called prides. There are as many as 35 males, females, and cubs in a pride. All the females in a pride are related. The females in the pride hunt together and care for cubs together.

The males in a pride are not always related. Males join a female pride to mate and produce cubs. Males do not help care for cubs. Males patrol their territory. They try to keep rival males away from their pride.

When female cubs grow up they stay with the pride. Males must leave the pride.

HUNTING AND EATING

Female lions do most of the hunting. Lions like to hunt at night. They hunt alone or in groups. A lion alone often hunts smaller prey such as hares or warthogs. The lion slowly and silently stalks the animal. If the prey sees the lion and runs, the lion usually gives up. When the lion gets close enough, it suddenly runs for the prey. It grabs the animal with its teeth and claws, pulls it to the ground, and kills it.

Groups of lions hunt large prey, such as buffalo, zebras, and even giraffes. A group of lions may surround an animal to trap it. Some lions may drive the animal toward waiting lions. Two or more lions grab and bring down the animal. Lions also steal prey killed by other animals, such as hyenas.

The pride eats together. Males eat first. Then the females eat. Cubs eat last.

A HARD LIFE

Lions do not have an easy life in the wild. They starve when they cannot find food. They get injured or killed while hunting or fighting with each other. They suffer from diseases.

Males have bloody fights. Younger males challenge older males for leadership of a pride. Sometimes they drive the older males away.

Females fight with the new males. The new males try to kill cubs that were fathered by the other males. Females are too small to fight male lions one on one. But the pride females may join together to save their cubs.

Male lions only live about 10 years in the wild. Females live a little longer. In zoos where they are cared for and cannot fight, lions may live as long as 25 years.

THREATS TO LIONS

Lions once roamed all over Europe, Africa, the Middle East, and Asia. People have hunted and killed lions since ancient times. They have also hunted the animals lions need for food. In many places, people have destroyed the areas where lions lived by building towns, roads, and farms.

There are about 100,000 lions left in the world. Only a few hundred Asian lions live in India. Most lions live on game reserves in Africa. Thousands of lions also live in zoos and circuses around the world.

动物的资料

名称

学 名：Ailuiopodidae melanoleuca

别 名：花熊 华熊 竹熊 花头熊 银狗 大浣熊 峨曲 杜洞尕 执夷 貊 猛豹 猛氏兽 貘 食铁兽 猫熊

英文名：Giant Panda

分类

食肉目(Carnivora)熊科(Ursidae)大熊猫亚科(Ailurinae)

濒危信息

CITES：附录I

IUCN：濒危

国家重点保护等级： 一级

中国濒危动物红皮书等级： 濒危

外形特征

大熊猫体型肥硕似熊，但头圆尾短，头部和身体毛色黑白相间分明。

分布范围

只限于我国长江上游向青藏高原过渡的高山深谷地带，包括秦岭，岷山、邛崃山、大小相岭和大小凉山等山系。秦岭山系分布于南麓，主要分布的县是佛坪，一般分布的县是洋县，仅有少量分布的县有太白、宁陕、周至等。岷山系除甘肃文县为一般分布外，其余都分布于四川。在四川主要分布的县有平武、青川和北川等三县，一般分布的有南坪、松潘、茂汶等县，少量分布的县有安县、绵竹、彭县、什邡和都江堰市。邛崃山系主要分布的县有宝兴、汶川和天全等，一般分布的县有大邑和芦山，仅少量分布的县有邛崃、崇庆、康定、泸定等。大小相岭除洪雅和冕宁为一般分布县外，仅有少量分布的县有荥经、石棉、汉源、九龙等。大小凉山除马边、美姑和越西有一定数量外，仅有少量分布的县有甘洛、峨边和雷波等（潘文石，1988；马国瑶，1988；胡锦矗，1985）。 生境与习性 大熊猫栖长江上游各山系的高山深谷，为东南季风的迎风面，气候温凉潮湿，其湿度常在80%以上，故它们是一种喜湿性动物。它们活动的区域多在坳沟、山腹洼地、河谷阶地等，一般在20°以下的缓坡地形。这些地方土质肥厚，森林茂盛，箭竹生长良好，构成为一个气温相对较为稳定，隐蔽条件良好，食物资源和水源都很丰富的优良食物基地。

生活习性

除发情期外，常过着独栖生活，昼夜兼行。巢域面积为3.9-6.4km2不定，个体之间巢域有重叠现象，雄体的巢域略大于雌体。雌体大多数时间仅活动于30-40公顷的核域内，雌体间的核域不重叠（胡锦矗等，1985）。食物主要是高山、亚高山约50种竹类，偶食其它植物，甚至动物尸体。日食量很大，每天还到泉水或溪流饮水。性成熟期是6.5-7.5岁，多于4月发情。一般于当年9月初在古树洞巢内产仔，每胎多产1仔，偶尔也产2仔。幼仔随母体一岁半后才离开母体。野外雌雄性比约为1:1（梁齐慧，1993；魏辅文，1994）。

至危因素

1、森林采伐。大熊猫栖息地每年的采伐面积达到至少1万公顷。其栖息地每年以大约2.5 km2的速度在消失（Kleiman et al，1991）。近30多年来，陕、甘、川三省大熊猫分布区内人口倍增，已达43万余人，大型森工企业自1950-1985年共达27个（不含县属伐木场），采伐的森林核实面积为42万多公顷，年均伐木面积为2万多公顷，致使栖息地由70年代初31,450km2，经过15年后，已锐减至13,921.52km2，减少面积达17528.48km2，占原栖息地的56％，并造成6个伐区内熊猫消失，10个伐区内仅残存极少数熊猫，种群数量急剧下降（胡锦矗，1993）；

2、捕捉过多。如在解放前汶川县草坡，英、美等西方国家，在那时收购捕捉活体达20多只(猎杀者在外)，致使那里的大熊猫种群，迄今已逾50余年，数量仍然很少，尚未恢复。又如宝兴县从1963年迄今，仅在一个县内，捕捉的大熊猫就达113只以上。从50年代中期开始，从野外捕捉的熊猫已超过240只到国内外展出，其中又集中在宝兴110余只，平武60余只，致使这两个县种群结构被破坏，数量大幅度下降（胡锦矗，1993）。根据大熊猫生命表分析，它们一个世代约需12年，种群增长很慢，如大量捕捉，即使在保护得好的情况下，也需几十年才能恢复；

3、近些年来，盗猎走私大熊猫皮张标本尚时有发生；

4、大熊猫种群分布在25个以上岛状隔离的生境中。这些隔离的生境区大小为205km2（30-2384km范围），其中大多数（67％）的面积少于350km2（Kleiman et al.，1991）。这种种群的孤立和分割则是长期威胁其种群的重要因素，小群体的近交衰退现象将降低繁殖力、幼体成活率以及对疾病的抵抗能力。最终”岛状”成员将消失。据潘文石等（1988）对秦岭熊猫种群的遗传分析，那里有200余只大熊猫，可构成一个约90只的繁殖群体，其世代杂合率递减率为0.54％，经过12代后即140年后，每个成员都将有1/8的基因相同，相当于表（堂）兄妹的亲缘关系；

5、由于人类活动范围扩大，大熊猫被迫退缩于山顶，竹种十分单纯，一遇竹子开花，将无回旋余地，仅1975年岷山地区箭竹开花，死亡达138只以上；80年代邛崃山冷箭竹大面积开花，灾后发现大熊猫尸体108具，抢救无效死亡33只，共计141只（胡锦矗，1993）；

6、在大熊猫栖息地存在未经政府允许的矿产开发、污染以及矿工的伐树和捕猎也是威胁之一（Kleiman et al.，1991）。

自然历史

大熊猫是一种有着独特黑白相间毛色的活泼动物。它的拉丁名：Ailuropodamelanoleuca，指的就是它黑白相间的外表。大熊猫的种属是一个争论了一个世纪的问题：它究竟是属于熊科，或象小熊猫一样接近浣熊科，还是自成一种？最近的DNA分析表明，大熊猫属于熊科，代表了熊科的早期分支。成年熊猫长约120－190厘米，体重85到125公斤。独特的特征包括：大而平的臼齿，它的一根腕骨已经发育成了”伪拇指”这都是为了适应以竹子为食的生活。与其他六种熊类不同，大熊猫和太阳熊都没有冬眠行为。

食物特性

大熊猫的食谱非常特殊，几乎包括了在高山地区可以找到的各种竹子，大熊猫也偶尔食肉（通常是动物的尸体）。大熊猫独特的食物特性使它被当地人称作”竹熊”。竹子缺乏营养，只能提供生存所需的基本营养，大熊猫逐步进化出了适应这一食谱的特性。在野外，除了睡眠或短距离活动，大熊猫每天取食的时间长达14个小时。一只大熊猫每天进食12-38公斤食物，接近其体重的40%。大熊猫喜欢吃竹子最有营养，含纤维素最少的部分，即嫩茎，嫩芽，和竹笋。大熊猫栖息地通常有至少两种竹子。当一种竹子开花死亡时（竹子每30－120年会周期性地开花死亡），大熊猫可以转而取食其他的竹子。但是，栖息地破碎化的持续状态增加了栖息地内只有一种竹子的可能，当这种竹子死亡时，这一地区的大熊猫便面临饥饿的威胁。

圈养及社会行为

“繁殖困难”被作为新闻标题来描述大熊猫的繁殖状况。但是，野外的研究表明虽然大熊猫在圈养状态下寿命更长，但野外的繁殖成功率更高。在野外，成年熊猫不论雄雌都参与繁殖。雌性可以和几只争偶的雄性交配，同时一只雄性会寻找处于发情期的不同的雌性。交配的季节在春季三至五月份，通常不超过2－4天。怀孕期大约为5个月。野外偶尔会有孪生的情况出现，但是雌性熊猫一般只喂养一只幼崽。圈养种群中，孪生的情况较多。分娩之前，雌性个体寻找空树的根部和洞穴生产。它在这种庇护所里和附近要呆上三个月，用它宽大的手掌小心地照料幼崽。大熊猫的幼崽出生时非常小，通常只有100-200克，大概只有母熊重量的1/900。在大熊猫幼仔出生几天到一个月之后，母熊猫会把幼仔独自留在洞中或树洞里外出觅食。母兽有时会离开2天或者更长时间。这并不意味它丢弃幼仔，而是养育幼仔过程中很自然的一部分。幼仔在12个月左右开始吃竹子，但是在此之前，它们完全依赖于母亲。野外的幼仔死亡率比圈养要低，约40%左右（潘文石等,正在编印）。

在秦岭地区的长期研究表明大熊猫的繁殖率大概是0.654幼仔/雌性/每年（潘文石等，正在编印)，与北美棕熊的一些自然种群类似（Stringham1990）。

大熊猫是独居动物，每个成体的巢域明确，雄性个体的巢域通常很大，接近30平方公里，一般和多个雌性个体的巢域重叠。当雄性大熊猫在同一巢域相遇时，如发情期在雌性熊猫周围，它们之间有明显的等级，为争偶会导致争斗。占优势的雄性个体有和雌性交配的优先权，但其它雄性也还有机会。雌性个体在3－4岁时性成熟，雄性个体5岁左右。年轻的雄性个体在等级中位置较低，到7－8岁时才有机会交配。雌性个体从4岁到20岁，通常每2-3年产仔一次。虽然大熊猫唯一的家庭结构只存在母兽和不到一岁半的幼仔之间，大熊猫之间也会通过声音和气味经常交流，即使不是在发情期。大熊猫幼仔在一岁左右断奶，并一直和母亲在一起到一岁半左右，直至母亲再次怀孕。如果母兽未怀孕，幼仔会和母亲一起生活到两岁半，这时母亲将它赶走。独立之后，大多数的幼仔在母亲的附近居住，另一些，尤其是雌性，会远离出生地生活。大熊猫的行为仍需进一步的研究。

圈养大熊猫可以存活30年或更长，但野生大熊猫的寿命通常只在20年左右。

历史

化石显示，大熊猫祖先出现在2－3百万年前的洪积纪早期。大熊猫的栖息地曾覆盖了中国东部和南部的大部分地区，北达北京，南至缅甸南部和越南北部（夏勒，1993）。化石通常在海拔500－700米的温带或亚热带森林发现。大熊猫栖息地的巨大变化近代才发生。近几百年中国人口激增和占用土地，很多栖息地消失了。以前，大熊猫曾经生活的在低山河谷，现在已经成了居民点。大熊猫只能生活在竹子可以生长的海拔1200－3400米之间。

目前分布

野外到底有多少只大熊猫？这是一个很难回答的问题。居住在高山区陡坡的密竹林中，大熊猫的统计成为一项很艰苦的工作。在七十年代和八十年代曾经有过两次调查，估计野外有约1000只大熊猫，这个数字可能偏低。大熊猫分布区域内共有37个县，若按主产、一般和少量三级划分，主产县每县约有100只左右，共有7个县；一般产县每县约50只以上，共11个县；少产县每县常在50只以下，计有19个县。据此推算，大熊猫野生数量总计约有一千余只，圈养的数量约为100只AAAZPA Communique，1993）。大熊猫的净生殖率为1.0672，种群增长缓慢（四川省珍贵动物资源调查队，1977；毕凤洲等，1989）。根据国家林业局2006年的调查，目前全国有野生大熊猫1596只，圈养数量161只。大熊猫是熊科家族中最为珍稀，也是受到最大生存威胁的哺乳动物之一。大熊猫生活在中国西南青藏高原东部边缘的温带森林中，竹子是这里主要的林下植物。大熊猫的栖息地集中在六个独立的山系：陕西的秦岭山脉，甘肃和四川的岷山山脉，四川的邛崃，大小相岭和凉山山脉。八十年代调查统计的栖息地的面积约为13000平方公里（Reid and Gong 1999）。根据国家林业局2005年调查报告，现在已经确认将大熊猫秦岭种群认定为大熊猫新亚种。秦岭大熊猫和四川大熊猫在地域上已经分隔5万年之久，外形上秦岭大熊猫头部较圆。目前秦岭大熊猫的数量有273只。在秦岭山区，在黑白色大熊猫中发现过棕色大熊猫。

分类争议

大熊猫的分类地位一直有较大争议，大熊猫的祖先是拟熊类演变而来的始熊猫。现在国际上普遍接受将它列为熊科、大熊猫亚科的分类方法，目前也逐步得到国内的认可。国内传统分类将大熊猫单列为大熊猫科。