“If Smilodon is getting this big ... Next, meet the Entelodont, the horse-sized “hell pig” whose teeth were as thick as human wrists, and read about the 26,000-pound dinosaur that was ...

They include the largest dinosaurs and fliers to live in North America, strange mammals like tusked swamp beasts and a swift, voracious “hell pig,” and famous species like the Columbian mammoth.

A strange black rock found recently in eastern Mississippi turned out to be a tooth from a species of prehistoric creature occasionally referred to as “giant killer pigs from hell.” ...