Which sea bird can dive deeper than any other bird?

The emperor penguin is the deepest-diving bird known. Instrumented birds have reached depths of more than 560 metres while hunting beneath Antarctic sea ice.

Emperor penguins can remain underwater for around 20 minutes during exceptional dives. Their adaptations include dense bones, streamlined bodies, oxygen stored in blood and muscles, and the ability to reduce their heart rate while submerged.

They mainly pursue fish, squid, and krill. The emperor penguin is also the only penguin that breeds during the Antarctic winter. Males balance a single egg on their feet and cover it with a warm skin fold while females feed at sea. The king penguin is larger than most penguins but does not match the emperor's diving record.