The female bird is smaller and has vestigial wings. The function of the wing feathers is mainly to balance the body. The wing feathers are used in cold weather. In season, they are used to cover their featherless thighs to maintain body temperature and to court mates during mating. Adult birds also use wing feathers to protect young birds and eggs in their holes. The coat color of the female (Hens) is roughly similar to that of the male bird, except that the brown-gray coat is not as colorful as the male bird. The feathers of young birds (Chicks) are mottled brown and gray, and they must moult several times before reaching the adult feather color when they are two years old. This coat color is mainly for camouflage. The chicks of both sexes look very similar, and even the young ostriches are very similar. So far, it is still impossible to tell the male and female from their appearance, and they can only be distinguished by their sexual organs. The pelvis of the ostrich is closed, and the left and right pubic bones (Pubis b.) are healed in the midline. It is worth noting that ostriches urinate and defecate separately, unlike other birds.
The sexual organs of ostriches are very small before maturity; male ostriches have copulatory organs. During the mating season, the testicles of mature male birds are as big as a human fist, but they will shrink during the non-breeding period. They will not expand again until the next breeding season. The eggs are large and similar in color to duck eggs. They are 15-20cm long and weigh up to 1,400g. They are the largest among bird eggs. The egg shell is very hard and can withstand the weight of a person. The female bird is grey-brown, and the male bird has white feathers on its wings and tail.
The male bird can be up to 2.5 meters tall and can weigh up to 155 kilograms. The female bird is smaller and has vestigial wings. The function of the wing feathers is mainly to balance the body. The wing feathers are used to cover the naked body in the cold season. Feathered thighs are used to maintain body temperature and to court mates during mating. Adult birds also use wing feathers to protect young birds and eggs in their holes. Ostrich is a ratite walking bird. Therefore, there is a sternum and the keel is underdeveloped. The head is small in proportion, the brain weighs about 40 grams, the neck is about 90 centimeters long, the legs are about 1 meter long, and the feet have two toes, which evolved from the third and fourth toes. It is the only two-toed bird in the world. The male bird is black with white tail feathers, which are very valuable decorative feathers.
