At up to 40 kilograms in weight, the Emperor Penguin (Aptenodytes forsteri) is the largest of all penguin species. Emperor Penguins breed on fast-ice near the Antarctic coastline and are the only penguins to breed in winter. They are adapted to the extreme cold and wind, with several layers of feathers, large reserves of fat and small beaks and flippers to minimise heat loss. Up to several hundred birds huddle together for warmth, taking turns to occupy the warmest and coldest positions. One egg is laid in May or early June. The female gently transfers it to the feet of the male before heading out to sea to fish, leaving the father to incubate the egg, without eating, for around 65 days. Emperor Penguins can swim several hundreds of kilometres from their colonies in search of food.