<P> Like all penguin species, emperor penguins have streamlined bodies to minimize drag while swimming, and wings that are more like stiff, flat flippers . The tongue is equipped with rear - facing barbs to prevent prey from escaping when caught . Males and females are similar in size and colouration . 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 . In juveniles, the auricular patches, chin and throat are white, while its bill is black . Emperor penguin chicks are typically covered with silver - grey down and have black heads and white masks . A chick with all - white plumage was found in 2001, but was not considered to be an albino as it did not have pink eyes . Chicks weigh around 315 g (11 oz) after hatching, and fledge when they reach about 50% of adult weight . </P> <P> The emperor penguin's dark plumage fades to brown from November until February (the Antarctic summer), before the yearly moult in January and February . Moulting is rapid in this species compared with other birds, taking only around 34 days . Emperor penguin feathers emerge from the skin after they have grown to a third of their total length, and before old feathers are lost, to help reduce heat loss . New feathers then push out the old ones before finishing their growth . </P> <P> The average yearly survival rate of emperor penguins has been measured at 95.1%, with an average life expectancy of 19.9 years . The same researchers estimated that 1% of emperor penguins hatched could feasibly reach an age of 50 years . In contrast, only 19% of chicks survive their first year of life . Therefore, 80% of the emperor penguin population comprises adults five years and older . </P> <P> 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, displaying the widest variation in individual calls of all penguins . Vocalizing emperor penguins use two frequency bands simultaneously . Chicks use a frequency - modulated whistle to beg for food and to contact parents . </P>

How long do penguins stay with their mate