Although cats may be one of the most popular pets today, little is known about how and when humans and cats set up their close relationship.

    The earliest evidence for human–cat interaction dates back to prehistoric Cyprus(史前塞浦路斯), where the remains of a wild cat and a human — dated 9,500 years old — were found buried together

A new study in the Proceedings of the National Academy of Sciences has confirmed the first direct evidence of a human–domestic cat relationship among Chinese farmers 5,300 years ago. Researchers studied the bones of cats, dogs, deer and other animals unearthed in an excavation (挖掘) near a village in Central China. By using some ways, scientists showed that the cats were living on a mostly millet(黍)–based diet, just like the domesticated dogs and pigs from the site.

"The most reasonable explanation for a high consumption of millet–based food is that the cats had formed a stable and mutual relationship with humans and could easily feed on rodents (啮齿动物) around human villages, find leftover food or even have been fed by people intentionally," said Hu Yaowu from the Chinese Academy of Sciences in Beijing, whose research focuses on the relationship between humans and domesticated animals.

    "It is very interesting for us to find the consumption of millet-based foods by the cats, since this kind of evidence had long been missing.” Hu explains. Since cats usually eat meat, such a diet would be unexpected, unless the cats were being fed by people, the study argues. The researchers also found that one of the cats survived to reach old age, implying that it had a safe place to live and enough to eat.

Why the farmers wanted to keep cats nearby or make them "pets" could be answered by other evidence. Chinese archaeologists found some storage containers were specifically designed to keep out rodents — a vermin (害兽) that cats could certainly have helped with.

The simplified theory is that rats were attracted to the food of farmers, and so were harmful to farmers. Cats were attracted to the rats, and so farmers formed a mutually beneficial relationship with cats, taking care of them in return for pest control.

    Do you know what the hump(驼峰) of a camel is used for? If you answered to store water, guess again. In fact, a camel's hump is a place for storing fat.

    Most animals, including humans, store fat throughout their bodies, under their skin. But camels store their fat in one place, their hump. A hump can weigh as much as 80 pounds. Why do camels keep their fat this way? The answer is most likely because of their environment. Camels can go up to two weeks without eating because they have this fat to live off.

    Also camels are great at handling(处理，应付) changes in body temperature. Their humps can help the camels keep cooler. Their coats also help them adapt(适应) to the heat. While the coat is thick, it reflects(反射)the sunlight and protects the camel from the heat that rises off the desert sand.

    There are two kinds of camels, those with one hump and those with two humps. Camels with one hump are called Dromedary or Arabian camels. They live in the dry deserts in West Asia. Camels with two humps are called Bactrian camels. They live in Central and East Asia.

    Besides their humps, camels have a lot of interesting facts. They can live between 40~50 years. They can carry about 400 pounds and run up to 40 miles per hour. It's true that camels can go long time without drinking water, and they can drink about 26 gallons of water at a time. Camels can also close their nostrils(鼻孔). So whether a camel has one hump or two, it is one amazing animal that is very well adapted to its environment.

    We need animals. Every animal has its place in the balance(平衡) of nature. We should try to help save the animals.

    Some people think zoos are good places. The zoos give the animals the comfortable and safe living places. If the animals get hurt or ill, people will take care of them. The zoo is a good place to know the rules in the wild world. We can be much closer to nature. We can know more about the animals in the zoos by watching, listening even smelling instead of just looking at the pictures in books.

    Some people don't think animals feel happy in the zoos. Animals like pandas, wolves and bears usually live in the wild. They play and find food by themselves. They are free and happy in the wild. If they are in the zoos, food is enough and rooms are comfortable. They do not need to do their best to find food to eat or places to stay in. They just walk around, sleep day and night, but they are not free at all.

    I think we should build national parks as wild life nature reserves to protect animals. If we do nothing, animals will get fewer and fewer.

    When you are waiting on a phone call with a pen in your hand or feeling bored on a train, you may probably doodle(涂鸦). Consultant Graphology(笔迹咨询师)Tracey has studied the most common doodles and their meaning in a new piece of research. Here she shares the psychology(心理学)behind those doodles.