A Joke

I’ve read a joke lately in my grammar book. It says:
“A woman is outside her house. A dog is near her. A man walks by and is interested in the dog. He wants to pet the dog, so he asks the woman,” Does your dog bite?” The woman answers no. The man pets the dog and it bites him. He says,” You told me your dog doesn’t bite.” The woman answers,” This is not my dog. My dog is in the house.”