When being pursued by a predator , they have been known to reach speeds in excess of , and can maintain a steady speed of , which makes the ostrich the world 's fastest two-legged animal .
When being pursued by a predator , they have been known to reach speeds in excess of 70 km/h , and can maintain a steady speed of 50 km/h , which makes the Ostrich the world 's fastest two-legged animal .