Why do animals become more aggressive as they get older

As animals mature, they need to compete with others in order to breed and survive.

In infancy and throughout adolescent growth, most animals do not actively require these instincts. However, after maturation defending their territory from others becomes crucial to finding food, mates, and so forth.

Please best-answer me if I've been helpful!

Many animals may become more aggressive after having to live on their own, fending for themselves. All the dangers in the wild scare them into not being able to trust a lot of things. Until they realize your not a threat, they will act as if your are just another predator. It's just the way of life. It's how they survive.

Everything gets harder as you get older, I know, I get grumpier everyday. Animals suffer from the same ailments as humans do, arthritis, aches and pains, chronic disease and like humans may lose their eyesight.

I don't see that. Do you have an example?

In some cases, over-aggression (also called "correction") can be triggered by "young whipper snappers" blindly challenging a behavior or system that works.