Tyrannosaurids are built around raw bite force: a deep, heavily reinforced skull, thick banana-shaped teeth designed to crush bone as well as flesh, and a bite strength among the highest ever estimated for a terrestrial animal. Their forelimbs, by contrast, were small and two-fingered, a trait shared across the family despite the animals' otherwise massive builds. The family is generally split into two subfamilies -- the earlier, smaller-bodied albertosaurines and the later, larger tyrannosaurines.
Fossils place the family's peak in the final 20 million years of the Cretaceous, across western North America and East Asia. Tyrannosaurus rex, discovered by Barnum Brown in 1902, remains the largest and most famous member; close relatives like Albertosaurus, Daspletosaurus, and the Asian genus Tarbosaurus (a near twin of Tyrannosaurus) fill out a family whose members were consistently the largest predators in their respective ecosystems.