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Tinamous and Ratites: Struthioniformes

Behavior And Reproduction

Ratites and tinamous are diurnal, meaning they are most active during the day. The exception is the kiwi, which is nocturnal, meaning it is most active at night. Behavior and reproduction varies between families. All lay eggs in nests but there the similarities end. In tinamous, rheas, cassowaries, kiwis, and emus, the males incubate (sit on to keep warm) the eggs and raise the young chicks. In ostriches, the males sit on the eggs at night and the females during the day.

Ostriches are the largest living birds and live in flocks, families, and individually. They are diurnal, meaning that they are most active during the day. Ostriches can run at speeds of up to 45 miles per hour (70 kilometers per hour). Males are polygamous (puh-LIH-guh-mus), meaning they take more than one mate at a time. Ostriches have an average of thirteen eggs per nest, and a number of females will lay their eggs in a single nest. The eggs take about forty-two days to hatch. On average, only one chick per nest will survive to adulthood.

Emus are the largest bird native to Australia. They live in pairs and are nomadic, following the rain to feed. The female lays a large, thick-shelled, dark green egg. When a nest has about eight to ten eggs, the male incubates them, meaning he sits on the eggs to keep them warm until they hatch.

Kiwis are shy, night birds with a keen sense of smell. They pair up for life and are monogamous (muh-NAH-guh-mus), meaning they have a sexual relationship with only one partner. The female usually digs a nest in the ground where she lays one or two large eggs, weighing about 1 pound (0.45 kilogram) each.

Rheas are the largest birds in South America. They are polygamous. During breeding season, the male rhea builds a nest in which between two and fifteen females lay their eggs. Nests contain ten to sixty eggs. The male cares for the chicks for about thirty-six hours after they hatch.

Cassowaries are solitary birds except during mating and the egg-laying period. Although they do not fly, they are good swimmers and fast runners. The female lays three to eight large dark bright green eggs in a nest that is incubated by the male. He cares for the chicks for nine months after they hatch.


A ratite known as the elephant bird (family Aepyornithidae) of Madagascar was the largest bird known to exist. It reached a height of 10 feet (3 meters) and weighed up to 880 pounds (400 kilograms). Seven species of the elephant bird once existed and two survived into the first century. All are now extinct. The last species to survive was Aepyornis maximus, which became extinct around the year 1600 C.E. One egg of the elephant bird was so large it would take 150 chicken eggs to fill it.

Tinamous are one of the oldest families of birds. They are very shy and are rarely seen by humans. The male builds a nest and two or more females lay eggs in it. The male incubates the eggs and soon after they hatch and leave the nest, he signals for new females to lay eggs.

Additional topics

Animal Life ResourceBirdsTinamous and Ratites: Struthioniformes - Physical Characteristics, Behavior And Reproduction - GEOGRAPHIC RANGE, HABITAT, DIET, RATITES TINAMOUS AND PEOPLE, CONSERVATION STATUS