Any animal feels pain, but wild animals, strange as it may sound, do not experience pain: about the differenceoli how sensations » and «boli as experiences» see Experiencing Pain.
For animals to scream, roar or squeal in pain is not at all natural: this does not reduce the pain, and there is no evolutionary sense in such behavior. Roars, squeals and screams of pain in animals have a different meaning — this is a learned behavior that is characteristic of 1) for some herd animals where mutual assistance is possible, 2) for puppies of most predators, where it is customary to take care of small ones, and 3) practically for all domestic animals living among kind people.
A wild cat, having fallen into a trap, does not yell and does not suffer. If the paw of a wild cat falls into a trap, the cat will not make a sound, because it knows that if it makes noise, they will eat it ahead of time. If, in the wild, an adult animal betrays its feelings — whether with whining, lameness, sad and dreary eyes and slow movements, it will be eaten ahead of time. Moreover, in the animal community, the laws are extremely strict: if you suffer, they will bite you to death so as not to attract attention. Chickens, piglets — kill their sick relatives.
If in the wild an animal began to limp, this means that it simply no longer has the strength not to limp. The horse begins to lame only when there is no more strength to endure. Cows also do not show suffering — they grind their teeth at most. Because of this, by the way, for a long time there was a belief that animals do not feel pain. If the pain is accompanied by sounds, it is mainly only as a warning to comrades that somewhere something is bad and you need to save yourself.
Interestingly, it is among predators that children whine in pain more often. Why? Adult carnivores, more than herbivores, take care of their little children, and children quickly begin to understand this: if you whine, they will help you. We have already written that if a lynx or a wolf gets into a trap, they will not make a sound, rather bite off their paw and run away. But their children behave differently: if a little wolf cub is caught in a trap, it will howl, whine and attract attention to itself. Feelings and whining is an appeal for help to the elders and the strong.
As the animals came into life together with humans, their reactions to pain became more vivid and understandable. Namely, they learned to experience in a way understandable to others. Any puppy learns quickly: if you scream desperately when the owners are trying to punish him, the punishment will be mitigated. And we know: unlike a silent wild cat, a domestic cat, having pinched its paw, yells (suffers) for the whole apartment. Why, why? A domestic cat knows that people will come running to her signal to save her and help her. Suffering and all other experiences appeared only where there is someone who can respond to it with help.