New study of penguin fossils show the ancient birds were giant compared to today’s species.
The fossils were found years ago in New Zealand but were encased in rock that required careful excavation over a period of more than a decade, The Guardian reported.
The research announced Tuesday in the journal Nature Communications said 55 million to 60 million years ago, some penguin species were skinnier, had longer beaks, and measured 5 feet, 7 inches tall or taller, and weighed about 220 pounds. Current species, by comparison, only get as tall as about 4 feet, with many being much smaller.
The Kumimanu biceae penguins of the study, some of the species' oldest known, may have been predators that could swim up to 22 miles per hour, The New York Times reported, although then as now, they could not fly.
An analysis of the penguin fossils’ DNA showed a close relationship with birds such as albatrosses and petrels, both of which hunt for prey by flying over water.
Auks, which dive deep underwater, may be a precursor to these early penguins, the Times reported. The two species seem to have diverged about 66 million years ago during a time of mass extinction.
More than 50 species of penguin fossils have been discovered since the first ones were found in 1859, the Times reported, and the oldest of these were found in New Zealand. These older, larger species all became extinct about 20 million years ago, around the same time marine mammals like toothed whales and seals appeared in the oceans, The Guardian reported.
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