Emperor penguins

Emperor penguins, which can reach heights of 1.2 metres, glide through the cold sea off Antarctica. Credit: Paul Nicklen/Getty

Animal behaviour

Emperor penguins break their fast with night-time snacks

Expectant fathers don’t starve themselves as long as thought.

Emperor penguins are renowned for spending months without eating while they breed and incubate eggs — activities that they must complete on solid ground. Now, scientists have caught some of the birds sneaking off for late-night snacks.

Gerald Kooyman at the Scripps Institution of Oceanography in La Jolla, California, and his colleagues attached satellite tags to four emperor penguins (Aptenodytes forsteri) from the Cape Washington colony, which is one of the southernmost populations, in Antarctica. The researchers found that despite the birds’ reputation, the penguins left the ice during long Antarctic winter nights to forage for food in the sea.

This colony of penguins lives closer than many others to the ocean’s edge, which might allow the penguins to shorten their fasting periods and improve their condition — and so their chances of successfully incubating an egg to hatching. Any birds that move south as the climate warms might benefit from a shorter winter fast.