Anatomy: Troodon had a relatively large brain, a long skull, and one very long toe claw. It was about 6.5-11.5 ft (2-3.5 m) long and weighed about 110 pounds (50 kg). The long tail acted as a counterbalance and as a stabilizer during fast turns.

Diet: Troodon was a carnivore, a meat eater. It probably ate just about anything it could slash and tear apart with its sharp teeth and with its long-clawed fingers and toes.

Fossils: Troodon was discovered by Ferdinand V. Hayden in 1855. Troodon was named in 1856 by Joseph Leidy. Troodon fossils have been found in North America (Montana, Wyoming, and Alberta).