Sibling rivalry is a universal problem. You never know how kids are going to react when you bring them home a new baby sister or brother.
It's also a problem that exists in the animal world. Cats could take to their new furry sibling right away, or it could take weeks — even months — before they're able to happily co-exist.
When cat pawrents, Mackenzie and Peggy, brought home a new kitten to their cat Cosmo, a cat fight quickly ensued.