About King & Emperor Penguins

Residents of the twilight zone are known for their nightly feeding frenzy at the ocean surface, but sometimes it happens the other way around. Though they breathe air like we do, and they live mostly on Antarctic ice, Emperor penguins (as well as elephant seals and whale sharks) frequently visit the dark middle ocean in search of food— or to avoid becoming someone else’s meal.

We might chuckle at the sight of penguins waddling over ice and belly-flopping into iceberg-studded waters, but these flightless birds would put Olympic swimmers to shame. They’re known to hold their breath for 20 minutes while diving over 500 meters (1,640 feet) in pursuit of fish, crustaceans and squid. Thanks to their solid bones and a super-efficient circulatory system, they can withstand the crushing pressures increase with depth. While diving, Emperor and King penguins conserve oxygen by slowing their heart rates as slow as fifteen beats a minute. Lesser creatures (ahem, humans) that attempt such exertion in ice water without an oxygen supply or with a pulse this low would soon pass out. Not these royal birds!

King penguins, which live around the islands just north of Antarctica, use similar tactics, but don’t venture quite as far into the twilight zone due to their smaller size. They have been recorded as deep as 300 meters (1,000 feet) and snack primarily on lanternfish.

All penguins are uniquely suited to survive the extreme Antarctic cold, so a hunting trip to the twilight zone might actually be a reprieve from surface temperatures, which get down to -70˚F. Huddled into groups, their dense, downy feathers and thick layers of fat insulate them from these miserably cold conditions. As is so often the case with creatures of the twilight zone, penguins’ most incredible adaptations lie just below the surface.

Quick Facts

Common NameEmperor penguin; king penguin
Scientific NameAptenodytes forsteri (Emperor); Aptenodytes patagonicus (king)
SizeEmperor: 100 cm (39 inches) tall and 22-45 kg (49-100 lbs) King: 70-100 cm (28 to 39 inches) tall and 9-18 kg (21-40 lbs)
DiscoveryEmperor: George Robert Gray, 1844 King: John Frederick Miller, 1778
Eats what?Fish (especially Antarctic silverfish), krill, crustaceans, squid
Eats how?Dives deep and holds breath for up to 20 minutes while hunting under ice or in open ocean
Is eaten by?Giant petrels and other seabirds, leopard seals, orcas