I don't think it matters, I think it is just how we identify them...like when you introduce yourself, you usually same something about yourself, like where you live or your age or something that identifies you with the group your with. So with yorkies or all dogs and even little kids, ages and weights are usually mentioned. Or maybe people say it, cause that is the first thing that is asked..."oh, how old is he/she, how big....least wise I think that is why people do it
