The Emperor Penguin is the largest penguin in the world. Emperor Penguins grow to be approximately 100 to 130 cm tall, and weigh about 30 kg. Emperor Penguins are good at diving, and are said to be able to reach depths greater than 250 m. They can stay submerged for around 20 minutes, longer than any other kind of penguin. To avoid losing body heat and strength while living on the ice, penguins keep their bodies rounded, pulling in their feet and necks. Penguins walk slowly and awkwardly, but in the water they seem to fly, swimming with the greatest of ease. Penguins form large colonies for breeding on the thick ice layers surrounding Antarctica. Females lay one egg in early May, then leave the egg in the care of the male. The females head for the ocean to search for food to replenish the energy expended in laying the eggs, and for the chicks which will soon hatch. The male carries the egg on top of its feet to keep it from touching the cold ice, and covers the egg with the skin of its belly. The male remains standing like this for about two months, protecting the egg without taking a break even to eat or drink. The female returns to feed the chick by the time the egg hatches. The parents protect the chick from the cold by carrying it on their feet.