Buff, 5-Foot Prehistoric Penguin Found

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June 25, 2007 — Human-sized, muscular penguins with enormous beaks thrived in sunny Peru 36 million years ago, according to a paper published today in the Proceedings of the National Academy of Sciences.

Standing at 5 feet tall, Icadyptes salasi was preceded in Peru by yet another newly identified penguin species, Perudyptes devriesi, which lived there 42 million years ago and was about the same size (3 feet tall) as modern king penguins.

Since both were among the world's earliest known penguins, they represent an evolutionary stage somewhere between flying, winged birds and the waddling, flippered penguins of today.

Lead author Julia Clarke told Discovery News that the ancient Peruvian penguins had "less rigid, paddle-like flippers than living penguins."

Clarke, an assistant professor of marine, earth and atmospheric sciences at North Carolina State University, added that both prehistoric species also had "distinctly straighter and narrower pointed beaks, with that of Icadyptes being nearly twice the length of the beak of any living penguin."

This particularly long-beaked penguin also possessed "a massive arm bone," suggesting Icadyptes was one tall, buff bird.

Deep muscle scars on the back of the prehistoric penguins' skulls further indicate they had extremely powerful jaws that could snap shut to catch and squash prey, which probably consisted of big fish.

"From these new finds, we now believe that a narrow, pointed, spear-like bill may be ancestral to the penguin lineage, and the very different beak shapes seen in some living penguins that feed on small invertebrate animals evolved much later," Clarke explained.

The new fossils call into question a popularly held theory about the timing and pattern of penguin evolution and expansion. The widespread belief has been that cold-adapted penguins evolved around the South Pole and then headed north towards equatorial regions around 10 million years ago, long after a period of cooling that began 34 million years ago.

Now the new fossil evidence suggests penguins evolved in Antarctica and New Zealand before heading northward more than 40 million years ago during one of Earth's warmest periods.

Prehistoric penguins, therefore, thrived in subtropical weather — an image that contrasts with the huddled, chilled masses of the birds seen today in colder parts of the Southern Hemisphere.

"It is quite possible that we have today one very recent remnant of the penguin group, maybe only 10-15 million years old that was adapted to cold conditions," Clarke said, adding that today's penguins are vulnerable to "current global warming," which is "occurring on a significantly shorter timescale."

R. Ewan Fordyce is a penguin expert and head of the Department of Geology at the University of Otago in New Zealand.

He said birds, such as those described in the paper, "probably reached twice the body mass of the largest living emperor penguins (121 to over 132 pounds), and maybe stood as high as an (adult) person's shoulder."

Fordyce also pointed out that the discoveries counter the theory that large body sizes evolved as an adaptation to cold temperatures. For penguins, just the opposite seems to hold true.

Another penguin expert, Steve Emslie of University of North Carolina's Department of Biology and Marine Biology, told Discovery News that scientists in the past had struggled with poor early penguin specimens where they didn't "know which leg bone goes with which wing bone for all of the species represented."

The Peru skeletons are more complete, he said.

Overall, Emslie said the new discoveries mark a "very significant" advancement in "our knowledge on the fossil record of penguins."