Why do dogs have the natrual instinct to hunt, chase, and even kill cats?

Mostly because you have not taught her NOT to chase and kill the cats. Dogs are pack animals and need a leader. If you are not the leader and show her how to behave, some of those old instincts will come out. It’s up to you to teach her properly. Get some help from a good trainer. Watch “dog whisperer” on National Geographic channel or buy is dvd’s for seasons 1 and 2 of his show. He showed a dog how to NOT chase small animals and kill them. They got to a point where the dog was laying on the ground and he put a bunny on his nose. The dog obeyed his pack leader and did not chase and kill the bunny. Your dog can do the same. Good Luck, you’re doggie is counting on you for good direction in life.

It isn’t just cats. Dogs have a natural instinct to chase anything that moves. It’s a hunting instinct– a predatory instinct. That’s why they play fetch. Without it they couldn’t survive in the wild.