Common ostrich
Common ostriches usually weigh from , or as much as two adult humans. The Masai ostriches of East Africa ("S. c. massaicus") averaged in males and in females, while the nominate subspecies, the North African ostrich ("S. c. camelus"), was found to average in unsexed adults. Exceptional male ostriches (in the nominate subspecies) can weigh up to . At sexual maturity (two to four years), male common ostriches can be from in height, while female common ostriches range from tall. New chicks are fawn in colour, with dark brown spots. During the first year of life, chicks grow at about per month. At one year of age, common ostriches weigh approximately . Their lifespan is up to 40–45 years.
Ratite
Ratite chicks tend to be more omnivorous or insectivorous; similarities in adults end with feeding, as they all vary in diet and length of digestive tract, which is indicative of diet. Ostriches, with the longest tracts at , are primarily herbivorous. Rheas' tracts are next longest at between , and they also have caeca. They are also mainly herbivores, concentrating on broad-leafed plants. However, they will eat insects if the opportunity arises. Emus have tracts of length, and have a more omnivorous diet, including insects and other small animals. Cassowaries have nearly the shortest tracts at . Finally, kiwi have the shortest tracts and eat earthworms, insects, and other similar creatures. Moas and elephant birds were the largest native herbivores in their faunas, far larger than contemporary herbivorous mammals in the latter's case.