October 30, 2008

Big Neanderthal Noses Served A Purpose

Big noses on Neanderthals were found to be a fluke of evolution by anthropologists, rather then some grand adaptation.

In the past, the Neanderthal nose has been a confusing matter for anthropologists.

They point out that modern cold-adapted humans have narrow noses to moisten and warm air as it enters the lung, and reduce water and heat loss during exhalation.

Big noses are more likely found in people whose ancestors evolved in tropical climates, where a large nasal opening helps cool the body.

Tim Weaver, a palaeoanthropologist at the University of California, said Neanderthals bucked that trend.

"They were living in the glacial environment of Europe, colder than it is today, for most of the time," he said. "So, it's sort of been an anomaly. Why do they have these wide nasal apertures?," he wondered.

Nathan Holton, a paleoanthropologist at the University of Iowa, said the old answer has been that Neanderthals have a big nose because they have a big mouth and a wide jaw, useful for ripping apart tough food.

"People have tried to explain the Neanderthal face as designed to produce high levels of bite force and trying to explain the rest of a wide nasal breath as part of a larger tend," he said.

Holton and University of Iowa colleague Robert Franciscus measured facial dimensions in dozens of Neanderthals and humans, ancient and modern.

The researchers could determine whether or not big mouths went with big noses, by correlating changes in the size of nose width, the distance between canine teeth, and other features.

Holton and Franciscus found a small link between nose and mouth, but it was not enough to explain Neanderthal noses.

"However, another measurement - the degree to which the face juts forward - seemed a better match for nose width," Houlton said. "If you want to change the breadth of the nose, you change the degree of facial projection," he added.

Recent research suggests that Neanderthals matured at the same rate as humans.

So, what did the research say about Neanderthals who have faces that jut further out than humans?

"They had them because earlier hominids had them," Houlton said.

Image Courtesy Wikipedia


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