Troodontidae

Troodontidae is a family of small, slender, bird-like maniraptoran theropod dinosaurs that lived from the Late Jurassic through the Late Cretaceous, radiating across North America, Asia, and Europe and possibly reaching the southern continents. Its members include the primitive Sinovenatorinae, the Jinfengopteryginae, and the more advanced Troodontinae, and the group is among the closest known relatives of birds. Troodontids had some of the largest brains relative to body size of any non-avian dinosaurs, along with large forward-facing eyes that gave them good binocular vision and enlarged, sometimes asymmetrical ear cavities that suggest acute hearing. They walked on unusually long legs and bore a curved, retractable claw on the second toe, though this "sickle-claw" was smaller and less strongly recurved than that of the dromaeosaurids. Their jaws held many closely spaced teeth, and while most were probably predators of small prey, the tooth form of some species points toward omnivory.