Actually body size is related to climate and large size is an
evolutionary cold weather adaptation. A large body loses heat slower
than a small body. Whitetail deer in Canada are the largest of all.
Northern states of Michigan, Ohio, Indiana, Illinois, North and South
Dakota, Iowa, Wisconsin and Minnesota have the large bucks that
hunters prefer. At just 18 months old, Ohio bucks in farm country
weight over 200 pounds. This doesn't seem possible to Southern hunters
but it is true.

Buck