Our cat Jax is a bob tail tabby. It wouldn't let me upload a picture of him for some reason, but he has only a nub for a tail. The kids have asked many times why he doesn't have a tail and I explain to them that its the kind of cat he is, all cats aren't the same, his parents didn't have tails either, just like some people have different color hair, cats are different types also. They have always been happy with my answer until Treyton shed some light on the issue...
"Mom, I know why Jax doesn't have a tail."
"Why is that buddy?"
"Well, when Noah was loading all the animals onto the ark Jax's old family was getting on the door accidentally shut on one of their tails and cut it off. God didn't want him to be the only cat with out a tail so he made more cats with short tails."
"Yup, that's probably why"
I love the way kids think!