Following trips to sea

An adult Emperor penguin carries a satellite tracker on his back
Image: R. Pike

To answer this question we must again rely on technology to obtain the answer. We attach small satellite tracking devices to the back of the penguins. These devices transmit signals every 90 seconds and if satellites are somewhere above them these signals are picked up and we get a location for the penguin. The aerial of the satellite tracker has to be exposed to air to work. So when the penguin is diving a lot we are less likely to get a location.

We equipped female Emperor penguins with satellite trackers just before they spent the winter in the pack-ice. In the 76 days or so they were absent from the colony they travelled 2600 km. Interestingly they were not more than 130 km away from the colony travelling backwards and forwards along the continental shelf break.

Examples of foraging tracks of female Emperor penguins in winter. The penguins stayed relatively close to the colony

In summer, the adult penguins travelled much farther! They tended to go north into very deep waters and then return to the fast-ice off the continent from 180 to more than 550 km west of their colonies. All these Emperor penguins had left their chicks and were fattening up before their moult.

Examples of foraging tracks of Emperor penguins in summer. The penguins travelled over 600 km away from their breeding ground and went much farther north than in winter