These days a video from the Beijing Wildlife Zoo goes viral (走红). What is so interesting about this video? It shows a dog playing with lions and tigers four to five times its size! Is the dog in danger? Of course not. 【小题1】 Animals make friends with members of a different species (种类).

A zookeeper said that they raised the dog together with the lions and tigers when they were very young. They were a strange but loving family. If you think this is too amazing, just remember that people have made friends with animals for a long time. 【小题2】 Maybe you have a pet yourself.

There are some other stories of cross-species friends. At an animal center, a cat named Marina and a pig named Laura became friends after they came to the center. 【小题3】 They grew up in the wild (野外) without their mothers’ care. They were close to each other and played happily together when they first met.

Why can different species be friends? In the wild, animals are busy hunting for their food. They have to work hard to keep themselves safe and protect their families. 【小题4】 When they needn’t do these things, animals will not have much to do. So it’s possible for them to make friends with members of other species.

Hamsters (仓鼠) are tiny, fuzzy and chubby (胖乎乎) animals. When people see hamsters putting food in the cheeks (脸颊), they can’t stop laughing. Hamsters’ big cheeks make themselves look cute. The cheek pouch (颊囊) is not only cute. It is useful, too. A hamster uses it like a bag. When the hamster finds something delicious, it hides it in its pouch. Peanuts, grapes, carrots—there are lots of delicious snacks in its “bag”. Will it get full and break? NO worries. The pouch can expand (伸展) to about three times its size! It might win the Guinness World Record (吉尼斯世界纪录) for having the biggest mouth!

Evolution (进化) gives a hamster the pouch because it’s so small and weak. The hamster has many enemies (敌人) in the world, such as foxes, owls (猫头鹰), snakes and cats. Those animals may catch the hamster when it’s looking for food. When they show up (出现), the hamster has to run quickly. With the big pouch, it can run back home fast with both its life and its lunch. Otherwise (不然), it might die of hunger.

But the pouch also brings the hamster some not-so-cute problems. When foods stay in the pouch for a long time, they will go bad. The hamster can’t clean its pouch with a tooth brush. It hurts! It will stop eating.