Penguins 'marched to South America'
Updated on 25 June 2007
A race of giant penguins marched to equatorial South America during a time when the world was much warmer than it is now, scientists have discovered.
Researchers were surprised to find fossil remains of the 36 million-year-old extinct penguin, which stood over five feet tall, so far south.
Icadyptes salasi, and another smaller species found with it on the south coast of Peru, challenge previous conceptions about penguin evolution and expansion.
The birds were assumed to have emerged and adapted to cold climates in high latitudes. Some species then migrated closer to the equator, but not until eight to 10 million years ago, long after the warm Earth had started to cool, it was previously thought.
Dr Julia Clarke, from North Carolina State University in Raleigh, who led the scientists, said: "We tend to think of penguins as being cold-adapted species, even the small penguins in equatorial regions today, but the new fossils date back to one of the warmest periods in the last 65 million years of Earth's history. The evidence indicates that penguins reached low latitude regions more than 30 million years prior to our previous estimates."
The giant penguin would have been a formidable animal, scientists said. Its most unusual feature was a seven-inch long pointed spear-like beak, and it was powerfully built with strong neck muscles.
The other prehistoric penguin discovered in Peru, Perudyptes devriesi, lived about 42 million years ago and at three feet tall was about the same size as a modern King Penguin. Most creatures moving from cold to warm climates tend to get smaller, since they do not need to conserve so much heat.
But Icadyptes salasi remained large even though the Earth at the time had not yet reached the end of a long spell of global warming. The cooling period which produced the permanent polar ice caps that still exist today began about 34 million years ago. The fossils are described in the journal Proceedings of the National Academy of Sciences.
By making comparisons with other ancient penguins, Dr Clarke and her colleagues estimate that the two species arrived in Peru from different parts of the world.
The ancestors of Icadyptes are thought to have originated near New Zealand, while Perudyptes hailed from Antarctica. Dr Clarke warned that it would be a mistake to assume that present day penguins facing climate change would be equally adaptive.
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