Even though they spend most of their lives in the water, they still need to rest on ice sheets after swimming long distances or to escape from predators like sharks or killer whales. They also need ice sheets to lay eggs and raise their young. For the past 50 years, global warming has caused sea ice in Antarctica to melt faster than usual. This does not only destroy the penguins’ homes, but also affects their food source. The penguins feed on shrimp-like krill which depend on ice to reproduce. So less ice also means less food. They often swim far away from the coast to hunt for fish and squid. In this long distance swimming, they can rest on floating ice sheets, but without them, the food source is too far away for them to swim.