Okay, this may be a silly question, but my husband brought this up yesterday and it got me wondering. I watch a cute little ACD every other day so the poor thing doesn't have to be cooped up in a crate while her owners are gone all day. My husband and I were out back throwing the ball with them, and they both LOVE it. However, Fiona loves to just chase the ball and leave it where it stops. Jester will get the ball and bring it back to us. I know that chasing is in Fiona's nature because she's a herding dog, and Jester lives to retrieve (Anything...his ball, bone, Kong, weird stuffed animal thing, and our newspaper. Cliche, I know, but it's really cute!). My question is, how is it part of their nature to do these things? Why do retrievers retrieve? Why do herding dogs do what they do? I was just wondering how a breed's "job" is bred into them.