Deinonychosaurids lived between the Late Jurassic and Late Cretaceous periods, and contains some of the most efficient predatory hunters of their era. The group was very successful as a whole due to their strong evolutionary advantages, specifically their razor-sharp second toes, which could be used like a blade against prey. The deinonychosaurids are further divided into two further clades, the Dromaeosauridae and the Troodontidae. By some scholars' definitions, the terms Deinonychosauria and Dromaeosauridae are synonomous with each other, and can be used interchangeably to describe the same group of animals.
The Dromaeosauridae family includes possibly the most well-known member of the group, the Velociraptor, as well as other related species such as Deinonychus and Utahraptor. All share a common trait of being efficient predatory animals, as well as possible pack hunting techniques, similar to modern wolves or hyenas. The Utahraptor was likely the largest of the group, while the aptly-named Microraptor was the smallest, at a length of 40 centimetres.
The Troodontids were prolific during the late Cretaceous Period, and were of lighter and slimmer builds than that of their dromaeosaurid cousins. The most well-known member of this family is the namesake Troodon, but the family also contained other related species, such as the Saurornithoides.