A humpback whale we tagged while it was feeding off the Western Antarctic peninsula made a nearly 19,000km-round trip in 265 days, travelling north from Antarctica to its breeding area off Colombia and back. Whales migrate thousands of kilometres each year, gathering to mate and give birth in the tropics and subtropics during winter and then heading for cooler waters in higher latitudes to feast on abundant prey during summer.
Theories abound, but scientists still can’t agree on why whales undertake these epic migrations, or even how they manage to navigate vast ocean basins.
