cover & concealment

In the animal world, all animals show their feelings directly. For example, dogs will wag their tails when they are happy, male lambs would jump high if they are trying to attract the female lambs. However, of all the animals in the world, humans are the only animal to put a camouflage over their feelings. Only humans choose to conceal their feelings and not show what is on their mind. No one else except the person him/herself will know what is going through the person's mind.