Seriema age of four to five months. It is unknown when fledged chicks reach sexual maturity. There are two living species of seriemas. The red-legged seriema, or crested cariama ("Cariama cristata") is found from eastern Brazil, to central Argentina. It is bigger and nests on the ground or in bushes or trees up to above the ground. The black-legged seriema ("Chunga burmeisteri") is found in northwest Argentina and Paraguay. It nests in trees. These birds are thought to be the closest living relatives of a group of gigantic (up to tall) carnivorous "terror birds", the phorusrhacids, which are known from fossils
Red-legged seriema just as another finishes, or two sing simultaneously. The song can be heard several kilometres away; in Emas National Park, Brazil, in 1981–1982, observers often heard four red-legged seriemas or groups singing at once. The full song consists of three sections: The red-legged seriema prefers grassland habitat to any other. Though it likes to inhabit lush meadows near rivers, it will not readily move into wetlands or crop fields. It is usually seen singly or in pairs, but sometimes in groups up to four, apparently families. It typically walks on the ground and can easily run faster than a human