Caenagnathids share the toothless beak and lightly built skeleton of their close relatives the oviraptorids, and the two families are frequently discussed together as part of the same broader group of bird-like, herbivorous-to-omnivorous theropods. Caenagnathids tend to be more gracile, with proportionally longer limbs suited to fast movement, though complete skeletons remain rarer than for their oviraptorid cousins.
Much of what's known about the family comes from fragmentary remains -- isolated jaws and limb bones were long the primary evidence before more complete specimens like Anzu, nicknamed the "chicken from hell" for its combination of a beaked skull, clawed hands, and possible crest, filled out the picture. Chirostenotes and Caenagnathus, both from North America, round out the family's better-documented genera.