Everyone knows how similar chimpanzees (黑猩猩) are to humans. So it's no surprise that their greetings are also close to ours. The most common ways of greeting between chimpanzees are hand touching and hugging. Sometimes they also kiss each other. Some chimpanzees can even learn simple sign language. 

Giraffes seldom make loud sounds. Their necks can reach two meters in length, making them useful in greeting each other. When two giraffes meet, they may "shake" their necks and rub (摩擦) them against each other. This is to feel how strong and tall the other is.

Dolphins greet one another with whistles (哨声), They can hear other dolphins from many kilometers away. Every dolphin has a different whistle. When two groups of dolphins meet, they each choose a member to "talk" to the other group. The two groups can then travel together. Unlike most of the other animals, dolphins are smart enough to learn a new language by inventing and copying new sounds.