The simple meaning of this sentence is that people can disguise themselves and are not easy to identify.

Animals have always been animals. Animals cannot disguise themselves. No matter where they go, they are seen as animals. They are very real and exposed in front of people. They cannot disguise themselves as an animal. Man, pretending to be a kind gentleman. Even if it is dressed in human clothes, people can see that it is still an animal and that it still has the essential disposition of an animal. No one will be deceived by him, no one will be deceived by him. If it is an animal with a gentle temperament, people do not need to guard against its attacks. If it is a ferocious animal, people need to stay away from it early, because it is an animal and it will attack people. I don't need to be reminded that it shows itself in its own right, that it is aggressive, that it hurts, and that one cannot be deceived into befriending it.

But people are different. People are good at disguise and hide themselves. Human beings are inherently good by nature, and if they are similar in nature, they will be far apart in habits. This shows that people have a bad side, a vicious side, and even an animal-like disposition that attacks people. But here it is, people can pretend, people can pretend to be a gentleman on the outside, but sometimes they are not pretending. There is a kind side in human nature, so it is natural for people to encounter the kind side in people, but It is undeniable that people still have evil dispositions. As long as their own interests are not violated, everyone is a gentleman. But when their own interests are involved, when people are offended or angered, they will show the nature of animals to attack and hurt people.

Therefore, as the old saying goes, it is difficult to draw bones when painting people or tigers.