The ostrich (Struthio camelus) is the largest and heaviest of all birds, males reaching 9 ft (2.75 meters) and 344 lb (156 kg). With 2 inches (5 cm) in diameter, the ostrich also has the largest eyes of any land animal. Although it can’t fly, the ostrich compensates by being the fastest bird in the world. It is able to reach a peak of 44 miles (70 km) per hour on a short distance, with 10 to 16 feet (3 to 5 meters) strides and its outstanding stamina can daunt most predators : it can run at up to 31 miles (50 km) per hour for more than 30 minutes.