These enormous birds, usually taller than a human, live in the deserts and savannas of Africa. They are the tallest, largest, and heaviest birds alive, and one of the unique. Their relatively small head features the largest eyes (5 cm in diameter) of any land animal, protected by their long black lashes. A male has bold black-and-white markings that are used to attract females, while females are light brown. Ostriches have rather prehistoric-looking feet, and are the only birds with only two toes on each foot. The inner one is thick and strong, and is adapted for running. It has a formidable claw, 10 cm long, which may be used in defense. Ostriches live in flocks numbering 5 to 50, and are normally found alongside grazing animals such as antelope and zebras. During the breeding season, of about 5 months, flocks will occupy territories extending 2-15  km. Outside the breeding season, smaller, looser flocks of 2-5 members form. Ostriches have a lifestyle which is nomadic and mostly diurnal, being active early in the day as well as late.