Emperor penguin diving through ice at "Penguin Ranch"
 - Aptenodytes forsteri

The diving habits and abilities of emperor penguins have been studied for several years by researchers based at the US base at McMurdo Sound Antarctica. A non-breeding group of juveniles are taken to a place about 15 miles away from open sea and kept in a corral known as "Penguin Ranch". A hole is cut for them through the sea-ice and as it is so far from any other holes in the ice, the penguins are obliged to return to where they came from.

Observations on their diving habits and times are taken and they are sometimes equipped with depth recording equipment to show how often and how deep they dive to. The penguins show no signs of harm or distress from this treatment. At the end of the season, the fence is taken down and the penguins wander off to resume their lives as normal.