Aepyornis, a genus of gigantic flightless birds of the extinct elephant bird order. These birds resembled large, bulky ostriches. The largest were about 10 feet (3 m) tall and weighed nearly 1,000 pounds (450 kg). While the extinct New Zealand moas were taller, aepyornises are the heaviest known birds. They laid the largest bird eggs ever discovered. One egg was 13 1/2 inches (34 cm) long and had a volume of two gallons (7.6 liters). The egg cell it contained is the largest known animal cell. Fossils of the largest aepyornises are found on the island of Madagascar off the east coast of Africa. The birds are believed to have become extinct 500 to 700 years ago. The aepyornis probably gave rise to stories about the roc, a gigantic bird of Arabic legend.
The largest elephant bird was Aepyornis maximus. It belongs to the single family in the elephant bird order, Aepyornithiformes.