The Irish Elk
If T-Rex was king of the dinosaurs, then the Irish Elk was king of all deer. It was the largest deer that ever lived, about 7 feet tall at the shoulders. It also sported the largest antlers of its family, measuring about 12 feet across and weighing about 88 pounds. In fact, Irish Elk antlers were so enormous that many scientists believe that they became too unwieldy and ended up causing the animal's extinction. Others suggest that, as with most megafauna of the time, early human hunters bear the blame for the Irish Elk's demise.