Quantcast
Connect with us

Prehistoric desert footprints are earliest evidence for Homo sapiens on Arabian Peninsula

Published

on

Humanity originated on the African continent at least 300,000 years ago. We know from fossil evidence in southern Greece and the Levant (modern-day Israel) that some early members of our species expanded beyond Africa around 200,000 years ago, and again between 120,000 to 90,000 years ago. They likely travelled through the Sinai peninsula, which formed the only land bridge connecting the continent of Africa to the rest of the world, before moving north into a landscape with a Mediterranean climate.

ADVERTISEMENT

But it was not known at what point humans turned south after crossing the Sinai peninsula, reaching modern day Saudi Arabia. It is also often assumed that they may have taken a coastal route, avoiding the currently harsh desert interior. Previous fossil finds show this was not the case, with humans moving into the heart of Arabia at least 85,000 years ago. Now, new research pushes this date back even further.

Colleagues and I discovered human and other animal footprints embedded on an ancient lake surface in the Nefud Desert in Saudi Arabia that are around 120,000 years old. These findings represent the earliest evidence for Homo sapiens on the Arabian Peninsula, and demonstrates the importance of Arabia for understanding human prehistory.

Map of modern day Saudi Arabia.

Key locations for early Homo sapiens outside-of-Africa (red stars). The Nefud Desert is highlighted inside the black rectangle. Google Maps

The Nefud Desert in modern-day Saudi Arabia lies around 500km to the southeast of the Sinai Peninsula. Today, the Arabian deserts are some of the most inhospitable environments in the world. They would form an impassable barrier for prehistoric humans or large mammals. Imagine standing at the foot of a hyper-arid desert equipped with stone tools and not much else. Could you get across? Probably not.

Scientific analysis shows that for most of their recent history, they were climatically similar to today: hyper-arid and impassable. But there is also evidence to show that at certain times in the past, the deserts transformed into savannah-like grasslands littered with freshwater resources. These “green” phases were likely short, probably lasting no more than a few millennia. Nonetheless, they provided windows of opportunity for humans and other animals to move into a new green landscape.

ADVERTISEMENT

We know from fossil lake sediments that the Nefud Desert was one of those that periodically transformed into a more attractive landscape in the past, and the new footprints prove that early humans took advantage of one such window.

Faint footprint in yellow rock.

First human footprint discovered at the Alathar ancient lake. © Klint Janulis, Author provided

Fossilised footprints

We were able to date the footprints by using a technique called luminescence dating to a period of time 102-132,000 years ago. Based on wider regional evidence for increased rainfall, we suggest they date to a period roughly 120,000 years ago, called the last interglacial.

ADVERTISEMENT

We know that around this time that vast river systems spread across the Sahara Desert, with Middle Palaeolithic archaeology scattered along them. Other evidence for increased rainfall at this time comes from fossil stalagmites found in caves in desert regions in Arabia and ~500 km north of the Nefud in the Negev Desert. These features only grow in conditions where rainfall is greater than 300mm per year; substantially more than the amount (<90mm per year) they receive today.

While it is difficult to know for sure which species of human left these prints, we think they were most likely left by our own, Homo sapiens. This is based on the fact that Homo sapiens were present in the Levant, 700km to the north of the Nefud Desert, at a similar time. Neanderthals were absent from the Levant in this period and did not move back into the region until thousands of years later, when cooler conditions prevailed. Estimates of the humans mass and statue based on the footprints are also more consistent with our species than Neanderthals.

ADVERTISEMENT

A man walks across a desert landscape.

Researcher surveying the Alathar ancient lake deposit for footprints. © Palaeodeserts Project, Author provided

High-res history

In addition to human footprints, elephant, horse and camel prints were also found. These footprints, studied in detail by Mathew Stewart at the Max Planck Institute for Chemical Ecology, provide a wealth of new information regarding prehistoric interactions between humans, animals and the environment.

Footprints are a unique form of fossil evidence as they provide precise snapshots in time that typically represent a few hours or days. This is a resolution we do not get from other records. They also allow us to understand the behaviour of their makers, which is something we cannot get from fossils.

ADVERTISEMENT

This allows us to understand the relationship between humans and other large mammals at a geologically precise moment in time.

Environmental analysis on the lake sediments show that the lake contained fresh “drinkable” water, while the variety of footprints shows that humans, elephants, camels and horses were using this resource at a similar time. Human and large-mammal movements would have been closely tied to fresh water and the pattern of footprints show both foraged on the lake bed when it was temporarily exposed. Humans may have been drawn to the area as they tracked large mammals, who would potentially serve as prey.

Animal prints in stone.

Animal fossils eroding out of the surface of the Alathar ancient lake deposit. © Badr Zahrani, Author provided

Surveys and analysis of fossils recovered from the site also shows that there are no stone tools or butchery of fossils. This indicates that the footprint-makers only very briefly visited the lake, foraging for resources before continuing on their journey.

ADVERTISEMENT

It is not clear what happened to the people who left the footprints, but evidence suggests that they, along with the other early Homo sapiens explorers, either died out or retreated to more favourable environments as aridity returned to the desert.The Conversation

 

By Richard Clark-Wilson, PhD Candidate in Geography, Royal Holloway

This article is republished from The Conversation under a Creative Commons license. Read the original article.


Report typos and corrections to: [email protected].
READ COMMENTS - JOIN THE DISCUSSION
Continue Reading

Breaking Banner

Senior DHS official slams Twitter after being locked out of account for ‘hate speech’

Published

on

On Thursday, Politico reported that Customs and Border Protection chief Mark Morgan lashed out at Twitter during a news conference on border wall construction, complaining that they had briefly locked his account under "hate speech" policies for tweeting his support of the wall.

The original tweet in question had stated that "every mile helps us stop gang members, murderers, sexual predators and drugs from entering our country."

Continue Reading

2020 Election

Here’s why counting 2020 votes could hinge on 13,500 misprinted ballots in Wisconsin

Published

on

Officials in Wisconsin are warning of delays in counting votes after 13,500 ballots were misprinted.

"The state Supreme Court declined to take a case Thursday that would tell officials in northeastern Wisconsin how to deal with misprinted ballots, raising the prospect of lengthy counting delays as clerks fill out thousands of replacement ballots on Election Day," Patrick Marley reported for the Milwaukee Journal Sentinel on Thursday.

Continue Reading
 

Breaking Banner

‘Signs of a coming conflict are everywhere’: Why a 2nd Civil War would be quite different from the 1st

Published

on

In 2020, the United States has been rocked by everything from a deadly pandemic and a brutal recession to civil unrest in a long list of cities to fears that violent conflicts will occur either on Election Day or after the election. Journalist Matthew Gault, in an article published by Vice this week, wonders if the political divisions in the United States run so deep that the country is headed for another civil war.

Describing the unrest that has occurred this year, Gault writes, "People are marching in the streets, aligned with two ideologically distinct factions. Many of them, overwhelmingly from one side, are armed, and violence and death has resulted when these two sides have clashed. The signs of a coming conflict are everywhere."

Continue Reading
 
 
Democracy is in peril. Invest in progressive news. Join Raw Story Investigates for $1. Go ad-free. LEARN MORE