Can penguins tell us how far the Cretaceous diving bird Hesperornis wandered?
Don't mess with Hesperornis. It was a flightless, aquatic Cretaceous bird that measured up to six feet long, had a beak lined with sharp teeth, and was partially responsible for the downfall of at least one scientific career. It superficially resembled a loon or a penguin–unlike penguins, though, Hesperornis probably propelled itself using its feet rather than its stumpy wings. Hesperornis also had a wide range–fossils within North America are known from Arkansas up to the Arctic Circle. Even during the comparatively balmy Mesozoic, winters would have been cold in the far north. Today's birds (including many penguins) with this kind of geographic range are often migratory–so was Hesperornis migratory with the changing of the seasons, or did it stay put year-round?