London, Oct 18 : Ancient humans dined on seafood as far back as 164,000 years ago, a new study by an Arizona State University anthropologist has revealed.

Curtis Marean and his team excavated a collection of shellfish remains, ochre pigments and stone blades, some of which were just a centimetre wide from a cave in South Africa overlooking the Indian Ocean.

The team dated the earliest material to 164,000 years ago.

Marean said the time frame matched exactly with estimates of sea level rise during that period.

He said this indicated that the cave was within easy walking distance of the shore about 167,000 years ago.

“Our findings show that at 164,000 years ago in coastal South Africa humans expanded their diet to include shellfish and other marine resources, perhaps as a response to harsh environmental conditions,” said Marean, a professor in ASU’s School of Human Evolution and Social Change.

“This is the earliest dated observation of this behaviour,” he said.

The earliest previous record of humans eating shellfish dates from about 125,000 years ago.

“Our research shows that humans started doing this at least 40,000 years earlier. This could have very well been a response to the extreme environmental conditions they were experiencing,” Prof. Marean said.

He said another co-occurring with this diet expansion was a very early use of pigment, likely for symbolic behaviour, as well as the use of bladed stone tool technology, previously dating to 70,000 years ago.

“We also found what archaeologists call bladelets – little blades less than 10 millimetres in width, about the size of your little finger. These could be attached to the end of a stick to form a point for a spear, or lined up like barbs on a dart – which shows they were already using complex compound tools. And, we found evidence that they were using pigments, especially red ochre, in ways that we believe were symbolic,” said Prof. Marean.

He said these new findings not only moved back the timeline for the evolution of modern humans, they also showed that lifestyles focused on coastal habitats and resources might have been crucial to the evolution and survival of these early humans.

The study appears in the Oct 18 issue of the journal Nature, reports New Scientist magazine. (ANI)