There's a lot of natural variance in this. There's no a priori reason that your 7.5 makes more sense than somebody else's 9. Or a house cat's 12-16. It's like a

There's a lot of natural variance in this. There's no a priori reason that your 7.5 makes more sense than somebody else's 9. Or a house cat's 12-16. It's like asking whether 5' 8" or 6' 1" is the correct height. You roll the genetic dice and they land where they land.