Саудын Арабын Нефуд цөл дэх эртний нуурын орчмоос олдсон хүний долоон мөр нь эртний хүмүүсийн нүүдлийн түүхийг өгүүлж байна.
Саудын Арабын Нефуд цөл дэх “Алатар” буюу “мөр” хэмээх нэртэй газраас олдсон эдгээр мөр нь 112,000-121,000 жилийн тэртээх үед хамаарч байгаа юм. Судлаачид эдгээр мөрийг Homo sapiens буюу орчин үеийн хүн төрөлхтний өвөг дээдэс үлдээсэн хэмээн тогтоожээ. Тухайн үед уг нуурын эрэг орчмоор заан болон тэмээ зэрэг амьтад явж байсан бөгөөд хүмүүс тус газраар түр саатан ус ууж байх үед нь тунадас хуримтлагдан мөрийг битүүмжилж хадгалсан байна.
Шинжлэх ухааны туршилтаар шаварлаг хөрсөн дээрх мөр нь ердөө хоёр хоногийн дотор бүдгэрч, дөрөв хоногийн дотор танигдахын аргагүй болдог нь тогтоогдсон байдаг. Ийм нөхцөлд 120,000 жилийн турш хадгалагдан үлдсэн нь археологийн хувьд ховор тохиолдолд тооцогдож байна. Гриффитийн их сургуулийн археологич Майкл Петраглиагийн тэмдэглэснээр, эдгээр мөр нь хүмүүс болон амьтад нэгэн цаг үед нуурын эрэг дагуу зэрэгцэн явж байсныг баримтжуулж байгаа юм.
“Ногоон Араб” хэмээн нэрлэгддэг чийглэг цаг уурын үед Арабын хойгт олон тооны нуур бүрэлдэж, хүмүүс нүүдэллэн ирэх боломжтой болдог байжээ. Мальтагийн их сургуулийн ахлах багш Хью Гроукаттын судалгаагаар, хүн төрөлхтний өвөг дээдэс 400,000-аас 55,000 жилийн өмнөх хугацаанд цаг агаарын таатай нөхцөлд тус бүс нутагт таван удаа нэвтэрч байсан нь тогтоогдсон. Гэвч тус газраас чулуун зэвсэг, нядалсан амьтны яс зэрэг суурин амьдралын шинж тэмдэг олдоогүй нь тэднийг түр хугацаагаар л саатсаныг илтгэж байна.
Судлаачид эдгээр мөрийг амжилтгүй болсон нүүдлийн нэг хэсэг байж магадгүй хэмээн таамаглаж байна. Генетикийн судалгаагаар өнөөгийн Африк тивээс гаднах хүн төрөлхтөн 50,000-80,000 жилийн өмнө Ази тивд тархсан бүлгээс гаралтай гэж үздэг тул түүнээс өмнөх нүүдэл нь мөхсөн байх магадлалтай аж. Цаг агаар хуурайшиж, нуурууд ширгэхэд хүмүүс усны эрэлд өмнө зүг рүү нүүдэллэсэн боловч тусгаарлагдсан жижиг бүлгүүд хатуу ширүүн нөхцөлийг давж чадаагүй байж болзошгүй гэж үзэж байна. Өнөөг хүртэл тухайн үеийн хүн амьдарч байсныг нотлох баталгаатай чулуужсан олдвор, эсвэл халуун уур амьсгалаас болж хадгалагдан үлдээгүй эртний ДНХ-ийн мэдээлэл дутагдалтай байгаа нь энэхүү судалгааны хязгаарлагдмал хүрээг харуулж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
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Seven human footprints preserved beside an ancient lake in Saudi Arabia’s Nefud Desert have held up to scrutiny for six years. They date to roughly 120,000 years ago, and the prints match Homo sapiens. What has shifted is the picture around them: the people who left them may have been part of a migration that failed.
The tracks sit at a site called Alathar, Arabic for “the trace.” Sometime between about 112,000 and 121,000 years ago, a handful of people walked a muddy lakeshore already churned up by elephants and camels. Sediment then sealed the scene, tracks and all.
Survival of the prints is remarkable in its own right. The original 2020 paper in Science Advances noted that an experimental study of modern footprints in mud flats found fine details lost within two days. Prints became unrecognizable within four. That Alathar escaped this fate is, frankly, a small miracle, and it is why researchers keep returning to the site.
A Desert That Kept Opening and Closing
Arabia was not always the arid place it is today. During “Green Arabia” periods, wetter weather filled the peninsula with lakes, and people could find drinking water where there is now only sand. Michael Petraglia, an archaeologist at Griffith University, says sites dated since 2020 suggest people entered Arabia in precisely those wet phases.
A 2021 study by Huw Groucutt, Petraglia and colleagues dated ancient lake deposits in the Nefud holding stone tools and animal fossils. The team stated that human ancestors moved into the Arabian interior at least five times between about 400,000 and 55,000 years ago, always during a wetter spell. Each phase had its own style of stone tools. According to Groucutt, a senior lecturer at the University of Malta:
“This looks like different populations, and indeed species, moving into the area at different times.”When the rains stopped, he adds, there probably wasn’t enough water for anyone to stay.
Passing Through, Not Settling In
Even during the good years, people probably kept moving. Groucutt, an archaeologist and senior lecturer at the University of Malta who studies human prehistory and environmental change, pictures groups traveling among scattered small lakes and other water sources, in a landscape that was still highly seasonal and marked by very hot summers. Settling down was not really an option: once the rains stopped, he says, there probably wasn’t enough water for anyone to stay.
At this site, the researchers found no stone tools and no butchered bones, the kind of debris that usually signals a longer stay. As mentioned in the press release, published in Max Planck Institute of Geoanthropology, they concluded that the lake “was only briefly visited by people,” most likely for drinking water. The ground there had already been churned up by elephants and camels, and the handful of humans who passed through left just seven footprints among hundreds of animal tracks. Petraglia, an archaeologist at Griffith University in Australia, sees real value in that brevity.
“Footprints capture a moment in time, illustrating that people walked along lakeshores at the same time as animals,” he says.
The Case for a Failed Migration
Groucutt notes that the dominant view from genetics holds that people living outside Africa today descend from groups who spread into Asia around 50 to 80,000 years ago. Earlier people, by that reasoning, died out, which makes the footprints “probably an example of an earlier, failed, migration.” Skhul Cave on Mount Carmel, where fossils of early Homo sapiens were found, is another site linked to this pattern.
As Arabia became drier, he believes people may have moved south in search of water. Their stone tools suggest that, once cut off from groups in the north, they started doing things their own way. But the south eventually dried out too. The gaps in the archaeological record suggest that some groups may have become too small and isolated to make it through the harshest dry periods. The lakes that once attracted people may have ended up trapping them. Proof is hard to come by. Fossils can be tricky to date and assign to a species, and ancient DNA in low latitudes “just doesn’t go that far back,” because hot places are bad for preservation.
“A securely dated human fossil or a long, stratified sequence showing human occupations across both wet and dry periods would be transformative,” Petraglia explains.
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