Period: The late jurassic - 150 milion years ago
Where: USA (Colorado, New Mexico, Oklahoma, Utah, Wyoming) and Africa
Fossil dimension: 10-14 meters long, 5-6 meters high
Quick facts: As North America's largest predator in the jurassic period, Allosaurus had a lifespan of 30 years but was sexually mature at ten. Two ridged crests on its snout may have signaled its health and breeding potential to prospective mates. Recent research shows allosaurus interaction with its kidn largely aggressive rather than cooperation, including during mating.