The ostrich is not only the largest bird in the world, it is also the fastest biped or two legged animal. How fast is an ostrich, it can run at speeds of up to 45 miles per hour, 75 kilometers per hour, with the top sprint recorded at 60 mph, 100 km ph. Ostriches cannot fly, but they are agile distance runners. They use their wings for display, and for balance if they are making a tight turn to avoid a predator. But predators need to be wary around an ostrich, they have very powerful legs, and a well-aimed kick can kill a lion.