Neanderthals commonly suffered from surfer's ear
You may be familiar with the annoying condition known as surfer's ear.
The ringing, fizzing and water-logged sensation combined with hearing loss and frequent infections is associated with a bony growth in the outer ear canal that's caused by long-term exposure to cold water or wind chill.
Despite its association with modern water sports, human species have suffered from surfer's ear — technically known as external auditory exostoses — for thousands of years.
"It's been very well known in prehistoric human skeletons for a long time," said palaeoanthropologist Erik Trinkaus of Washington University.
But it appears from new research published by Professor Trinkaus and colleagues it was much more common in Neanderthals than in early modern humans or most people living today.
They said the finding, published in the journal PLOS One, suggested Neanderthals may have spent time around waterways foraging for food and other resources.
"There have been arguments that Neanderthal spend very little time exploiting these resources, which can be extremely rich," Professor Trinkaus said.
Indeed, he said, no archaeological evidence of fish bones or tools for fishing have been found with Neanderthal remains.
"This is an indirect, biological form of evidence that they were spending a rather substantial amount of time exploiting aquatic resources.
"It sheds a further window on the capabilities, the adaptability of Neanderthals, that over the years, and still today by some people, are very much maligned and denigrated," he said.
Neanderthals lived throughout Europe and southwest and central Asia from 400,000 years ago up until about 40,000 years ago.
During this time the climate cycled between colder and warmer phases, and Neanderthals crossed paths with other species of humans, including early modern humans.
Professor Trinkaus and colleagues wanted to explore whether they could use the prevalence of surfer's ear in Neanderthals to glean information about their behaviour.
To do so, they compared the ear canals of 24 Neanderthals with those found in 45 fossils of early modern humans that lived in Europe either towards the end or just after the Neanderthal era, as well as a handful of other ancient human fossils.
While around a quarter of the early modern humans had growths — a frequency that was similar to a small sample of people living today — around half the Neanderthals examined had mild to severe bony growths.
But not all of the Neanderthals with the condition lived in extreme cold locations or times.
"Some of them were living in very cold phases in Europe and France as far north as Belgium. Others were living in the Mediterranean area during a climatic period not all that different to today," Professor Trinkaus said.
"What this tells is that they were frequently exposed [to cold moist air] in different climates."
Also, while some of the Neanderthal fossils were dug up along the coast in Gibraltar and Israel, others were found inland.
But that didn't necessarily preclude them from water activities, Professor Trinkaus said.
"These people were highly mobile on the landscape so where they were buried was part of their territory, their range, but it wasn't necessarily where they were most active in foraging or other kinds of activities."
"They all lived somewhere near water sources, it's a matter of how big they were."
Did Neanderthals forage for marine resources?
The new study adds to research that suggests Neanderthals may have had a wider range of food sources than previously suggested, said Steve Wroe, director of the Function, Evolution and Anatomy Research Lab at the University of New England.
"For a very long time it was considered Neanderthals basically went around with big pointy sticks getting in close and dirty with big hairy animals and killing them," Professor Wroe said.
"There's no doubt they were effective hunters, but it's become increasingly clear they certainly ate vegetable matter, they certainly fitted a bit more of a real hunter gather sort of group than just a purely carnivorous low-tech, high incidence-of-injury kind of people."
But, he said, even though the latest research certainly shows a much higher incidence of bony growths in Neanderthals than modern humans, this was "hardly conclusive" it was due to the exploitation of aquatic resources.
Luca Fiorenza of Monash University, who has studied the diet of Neanderthals, is also yet to be convinced our ancient cousins regularly hunted fish or other aquatic species.
Dr Fiorenza said shellfish and butchered bones of whales and dolphins found near Neanderthal remains in coastal areas indicated they consumed aquatic resources, but the lack of tools suggested they were scavengers.
"The problem is we have no evidence of tools that give direct evidence of Neanderthals hunting or fishing," he said.
Nor is there any evidence of fish bones with any of the skeletons, although, he said, this could be because fish bones are very delicate.
Dr Fiorenza said if the bony growths were related to water-based activity then the Neanderthals would have had to be in the water frequently.
"I'm not excluding the fishing component," he said, "but if you just fish a couple of times probably you wouldn't be able to develop this feature on the auditory canal."
"If there is a strong correlation between behaviour and this anatomical feature ... you would expect to find more archaeological evidence to suggest a strong exploitation of aquatic resources."
Isotopic analysis of chemicals in Neanderthal bones also points to a primarily terrestrial animal-based diet, he added.
Additionally, there may be a range of other factors at play.
"Generally Neanderthal have much thicker bones, so I don't know if that has any relation with the fact they've found this additional bone deposition in the ear canal," he said.
The researchers agreed that other factors such as genetic predisposition, and perhaps poor sanitation may play a role.
But this would not account for all the overall higher frequency, Professor Trinkaus said.
Fast forward thousands of years, and the condition is just as common in one subset of modern humans as that seen in Neanderthals.
Today, between 38 and 80 per cent of recreational and professional surfers have varying degrees of the condition.
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