It was relatively primitive, with feathers and three-fingered hands. It was small for a tyrannosaur, about 4 metres long, and to make up for this may have hunted in packs.
Its fossils have been found on the Isle of Wight, UK. The bones, including a skull, were described in 2001, and named Eotyrannus lengi. The type name honours its discoverer, Mr Leng.
Eotyrannus featured in the Primeval novel The Lost Island. A pack of Eotyrannus attacked Cutter and the group, and they retreated into a metal building for safety. However, the Eotyrannus followed, and attempted to break down the door. Several other dinosaurs were also featured in The Lost Island.