Adelie Penguins
Adelie penguins are members of the Pygoscelis, or stiff-tailed, genus of penguins. Due to their tame nature, they are one of the most frequently studied types of penguins.1,2 Adelie penguins are white and black, and completely unadorned except for a thin white ring around each eye. 1 Adelies are the typical, tuxedo-looking penguins that are most commonly featured in drawn pictures. Like all penguins, Adelie penguins are flightless birds.
Size
Height: 18-24 inches
Weight: 8-10 pounds
Food
Adelie penguins eat mostly krill and some fish. 4
Adelie penguins can live around the entire coast of the Antarctic continent while breeding. 2 The rest of the year, they may also live on nearby islands. 1
Adelies are named after the wife of a French explorer named Admiral Dumont d'Urville, who explored Antarctica in the 1830s. 1
Mating Habits
Males and females both return to land from sea at the same time. The males gather stones to make a nest. Then they sit at their nest and call out. The female Adelies walk around and look for a mate. 3
Since the males will be sitting on the eggs for weeks while the females eat at sea, the most important survival trait for the males is that they be as fat as possible. Thus, as the males call out, the females look for a deeper voice, indicating a fat male penguin who will be able to sustain himself on his body fat and guard the eggs. As soon as the female chooses a mate, the birds will mate. 3
Sometimes a female will recognize her mate from the previous year. If another female is found with her mate, she will fight the other female bird for the male. 3
Breeding Habits
Adelies nest on rocky ground in large colonies from tens of thousands to half a million birds.1,4 Females lay two eggs, then swim in the sea to feed for three weeks while the male penguin incubates the eggs.1 The male penguin keeps the eggs on the top of his feet and lies over them on the nest. If the male begins to starve, it will abandon the egg or chick and return to sea to feed. In that case, the female penguin will return to find a frozen egg or chick.3
Sometimes, only the first chick survives; the second is a back-up in case the first one dies. This is known as the "heir-and-a-spare" strategy.1 However, if food is abundant enough in the area, the Adelie penguins can often raise two chicks.3
Adelies are the fastest growing penguins. When they are old enough, the chicks live in groups called crèches. Twice each day, their parents leave and pass through a dangerous region of leopard seals to feed and bring back food for the chicks. When the parents return, they call out to their chicks, and the chicks sprint to their parents to get food.3
When the parent penguin comes to shore to feed the chicks, it often makes them chase it to get to food. The purpose of the chase is not entirely understood, but one possibility is that it insures the survival of the stronger chick if the penguins live in an area with a shortage of food. 1 If there's enough food, the stronger chick will stop chasing at some point and will allow the weaker chick to eat.3
Killer whales and leopard seals eat adult Adelie penguins. Skuas eat penguin chicks and eggs. 4 Because of a high mortality rate due to predators, most Adelie penguins don't survive more than three to four years. 1
Endangerment level
Adelie penguins have been classified as a Lower Risk population by the World Conservation Union. 4
Adelies and People
Even though Adelie penguins are relatively tame and show little fear of people, they will attack a human if they feel threatened. 1
According to the American Zoo and Aquarium Association, 174 Adelies currently live in captivity in North America. Zoos where they live include Sea World in Texas, Milwaukee Zoo, and Six Flags World of Adventure. 4
Sources:
1. Hastings, Derek. Penguins: A portrait of the animal world. Smithmark, New York; 1997. 72 p.
2. Sparks, J., Soper, T. Penguin. Facts on File Publications, New York; 1987. 246 p.
3. PBS special: Penguins.
4. Penguin Taxon Advisory Group. 2001. Species index, Last accessed 2004 Jan 18.