What Do Penguins Eat? Krill, Fish and Squid Explained

The three main foods of penguins

Every penguin is a carnivore that hunts at sea. Their prey falls into three main groups:

• Krill: small, shrimp-like crustaceans. Antarctic krill grow to about 6 cm (2.4 in) long and form vast swarms in the Southern Ocean. They are the main food of Adelie, chinstrap and macaroni penguins and an important food for gentoos.
• Fish: usually small schooling fish such as Antarctic silverfish, lanternfish, sardines and anchovies. Fish are the main food of most temperate and larger species.
• Squid: small squid are eaten by many species, especially the king and emperor penguins that dive deep.

Most penguins are flexible and switch between these foods depending on the season, the year and what is most common near their colony.

What does each penguin species eat?

The diet changes a lot from one species to another, largely because of where they live and how deep they dive.

The big Antarctic and sub-Antarctic penguins dive deep for their food. King penguins regularly hunt lanternfish at depths of 100–300 m (330–980 ft), and emperors have been recorded diving more than 500 m (1,640 ft). Smaller species usually feed much closer to the surface. Read more in how deep penguins can dive.

How do penguins catch and eat their food?

Penguins hunt by sight, chasing prey underwater with their flippers. Many species feed in daylight, when it is easiest to see. Some, such as African and Magellanic penguins, hunt in groups that push schools of fish toward the surface, where they are easier to catch.

Penguins have no teeth. Instead, their tongues and the roofs of their mouths are lined with stiff, backward-pointing spines called papillae. These work like a one-way conveyor belt: they grip slippery fish and krill and stop them from escaping, while helping the food slide down the throat. Penguins swallow prey whole, usually headfirst and often while still swimming, so they can catch many items on one dive.

Because they eat at sea, penguins swallow a lot of salt water. Like other seabirds, they have salt glands above the eyes that remove extra salt from the blood. The salty fluid drains out through the nostrils, which is why penguins often seem to have a “runny nose” and shake their heads.

How much do penguins eat?

The amount depends on the size of the penguin and the season. An African penguin, which weighs about 3 kg (6.6 lb), may eat roughly 500 g (1.1 lb) of fish a day, and more when feeding large chicks. Before they molt or start a long fast, penguins eat heavily to build up fat.

Fasting is a normal part of penguin life. During the annual molt, penguins cannot go to sea for two to five weeks because their new feathers are not yet waterproof. Male emperor penguins go without food for about four months during courtship and incubation, living on stored fat through the Antarctic winter.

How do penguin parents feed their chicks?

Penguin chicks cannot hunt, so their parents bring food back from the sea in their stomachs. When a parent returns, the chick begs by pecking at its bill, and the adult regurgitates partly digested fish, krill or squid straight into the chick’s mouth. In most species the two parents take turns, one guarding the chick while the other feeds at sea.

Emperor penguins have an extra trick. If the chick hatches before its mother returns from the sea, the father can feed it a small amount of a protein- and fat-rich secretion produced in his esophagus, enough to keep the chick alive for a few days. King penguin chicks face a different challenge: during the sub-Antarctic winter their parents visit only rarely, and the chicks can go weeks or even months without a meal, surviving on their fat reserves.

Penguins in the food web

Penguins are also food for other animals. At sea they are hunted by leopard seals, fur seals, sea lions, orcas and sharks, depending on the region, while gulls and skuas take eggs and chicks on land.

Because they eat the same krill and fish that people harvest, penguins are sensitive to overfishing and to changes in the ocean. In southern Africa, a shortage of sardines and anchovies has driven the decline of the African penguin, and in Antarctica scientists monitor penguin diets to help manage the krill fishery. When penguins have trouble finding food, it is often a sign that the wider ecosystem is under stress.