There is this insane misconception out there that cats don't care about anyone but themselves. Now, to us, cat owners, that statement couldn't be further than the truth. Cats, in fact, are extremely protective. Their loyalty is not easy to get, but once you have it, you have it for good. The thing about cats is that they see everyone as inferior to them, and while that might be funny, in reality, it only makes cats more protective of what they see as vulnerable - whether that's humans or other animals.
We have seen a cat adopt a puppy into her litter because she saw that it needed help. We have seen a cat lose her kittens in childbirth and take in a bunch of orphaned kittens to raise as her own instead. We have even seen a cat adopt a lynx cub and raise it alongside her kitten because, even though that lynx was very big for a kitten baby, it was still a kitten in need of help. And today, we have a cat who is obsessed with a human baby - its baby brother - and treats that baby as if it's a kitten in need of constant vigilant protection.