The greater roadrunner (Geococcyx californianus) is a long-legged bird in the cuckoo family, Cuculidae, from the Aridoamerica region in the Southwestern United States and Mexico.

[5] Greater roadrunner fossils dating from the Holocene and Pleistocene have been found in California,[6][7] New Mexico, Texas,[8] Arizona,[9] and the Mexican state of Nuevo León.

[11] Prehistoric remains indicate that until 8,000 years ago, the greater roadrunner was found in sparse forests rather than scrubby deserts; only later did it adapt to arid environments.

[18] This is the fastest running speed clocked for a flying bird, but not nearly as fast as the 40 mph (60 km/h) of the completely flightless and much larger ostrich.

The most frequent call is a slow and descending sequence of about six low, "cooing" noises, emitted by the male and which is heard at 820 feet (250 m).

[20] This call is usually made early in the morning, from a high perch such as a fence post, dead tree or cactus.

Females give off a number of up to twenty-two short, low-frequency shrills, resembling coyote squeals, which can be heard 1,000 feet (300 m) away.

It occupies arid and semiarid scrubland, with scattered vegetation (typically less than 50% cover) with a height that doesn't exceed 9 ft 10 in (3.00 m).

[24] Courtship behaviors between greater roadrunners are a lengthy process including a combination of chasing, tail wagging, play-fighting, and acoustic signals.

A unique feature of the greater roadrunner is that mated couples will continue their copulation rituals long after the need for egg fertilization.

The nests are compact platforms of thorny branches lined with grasses, feathers, snakeskin, roots, and other fine material.

[24] Similarly to some other cuckoos, greater roadrunners occasionally lay their eggs in the nests of other birds, such as the common raven[27] and northern mockingbird.

Some instances of the greater roadrunner feeding on the dead carcasses of larger mammals (including bats, ground squirrels, and one juvenile desert cottontail)[31] have been observed.

[23] Early pioneer accounts report that when the roadrunner "sees a rattlesnake, it will gather pieces of cactus and put them around the snake, in such manner that escape is impossible".

[33] Because of the greater roadrunner's diurnal nature and arid habitat, it has various biological and behavioral adaptations, known as thermoregulation, to reduce dehydration and overheating.

[35][36] The greater roadrunner reduces excess heat by the formation of water vapor, released by breathing or through the skin.

[5] Some Pueblo Native American tribes, including the Hopi, believed the roadrunner provided protection against evil spirits.

[45][46] The College of DuPage mascot takes the bird's alternate name, Chapparal, inspired by students driving between various temporary classroom locations before the main campus was fully constructed.

[47] Hoese, William; Anticona, Steve; Olmos, Erik; Parent, John; Rutti, Donald; Velasco, Beth (March 2013).