Emperor Penguin

The Emperor Penguin (Aptenodytes forsteri) is the tallest and heaviest of all living penguin species and lives in Antarctica. Feathers of the head and back are black and sharply delineated from the white belly, pale-yellow breast and bright-yellow ear patches.
Like all penguins, It is flightless with a streamlined body, and wings flattened into flippers. Its diet consists fish, but also includes krill and squid. While hunting, it dives to a depth of 535 m (1,755 ft)
The only penguin species that breeds during the Antarctic winter The female lays a single egg, which is incubated for just over two months by the male while the female returns to the sea to feed parents take turns foraging at sea and caring for their chick in the colony.
Description
Adult emperor penguins are 110–120 cm (43–47 in) in length, including bill and tail. It is the fifth heaviest living bird species, as both male and female penguins lose substantial mass while raising hatchlings and incubating their egg. A male emperor penguin must withstand the extreme Antarctic winter cold for more than two months while protecting his egg. He eats nothing during this time. Most male emperors will lose around 12 kg (26 lb) while they wait for their eggs to hatch. 
Like all penguin species, emperor penguins have streamlined bodies to minimize drag while swimming, and wings that are more like flat flippers The adult has deep black dorsal feathers, covering the head, chin, throat, back, dorsal part of the flippers, and tail. The black plumage is sharply delineated from the light-coloured plumage elsewhere. The underparts of the wings and belly are white, becoming pale yellow in the upper breast, while the ear patches are bright yellow. The upper mandible of the 8 cm (3 in) long bill is black, and the lower mandible can be pink, orange or lilac. Emperor penguin chicks are typically covered with silver-grey down and have black heads and white masks
Vocalisation
As the species has no fixed nest sites that individuals can use to locate their own partner or chick, emperor penguins must rely on vocal calls alone for identification. They use a complex set of calls that are critical to individual recognition between parents, offspring and mates Vocalizing emperor penguins use two frequency bands simultaneously. Chicks use a whistle to beg for food and to contact parents
Behaviour
Both male and female emperor penguins forage for food up to 500 km (311 mi) while collecting food to feed chicks, covering 82–1,454 km (51–903 mi)
An effective swimmer the emperor penguin exerts pressure with both its upward and downward strokes while swimming. The upward stroke works against buoyancy and helps maintain depth. Its swimming speed is 6–9 km/h (3.7–5.6 mph). On land, the emperor penguin alternates between waddling sliding over the ice on its belly, propelled by its feet and wing-like flippers. Like all penguins, it is flightless. The emperor penguin is a very powerful bird. 
Predators
The emperor penguin's predators include birds and aquatic mammals. Southern giant petrels are the land predator of chicks they also scavenge dead penguins. The South polar skua mainly eats dead chicks
The only known predator to attack healthy adults and who attack emperor penguins in the water, are both mammals. The first is the Leopard seal which takes adult birds and fledglings soon after they enter the water. Orcas mostly take adult birds, although they will attack penguins of any age in or near water.