Stone Age Animal Urine Might Remedy a Thriller about Technological Growth
Excessive on a sheer cliff in South Africa’s Swartberg mountain vary final September, College of Utah paleoclimatologist Tyler Religion lastly reached one thing he hoped would possibly clear up one in every of anthropology’s stickiest mysteries. His goal regarded like goo that had oozed from the sandstone cliff and hardened right into a foot-thick slab of black amber. Fuel masks on, Religion started working hewing away a 70-pound chunk; mud flung from his chainsaw shortly stuffed the air with a yellow-gold haze.
“It simply will get in your pores,” Religion says. “The second you soar within the bathe and that stuff lastly rehydrates, it is like: Think about probably the most pungent alleyway the place individuals have been peeing. It is superior. However yeah. All my gear now smells like pee.”
The substance is fossilized urine from untold generations of marmotlike critters known as rock hyraxes—and it acts as a superb report of the traditional local weather. Sticky and viscous like molasses, hyrax urine hardens shortly in air. It traps pollen grains and charcoal, telling scientists when explicit crops grew and wildfires raged. It additionally preserves chemical isotopes indicating precipitation and temperature. And the neat layers of the urine mounds or “middens,” which type the place the animals habitually relieve themselves, could be exactly radiocarbon-dated.
Religion and his colleagues are utilizing these clues to research controversial hyperlinks between historical local weather change and a dramatic technological leap that occurred between 66,000 and 25,000 years in the past, from the Center to the Later Stone Age: that is when our early ancestors developed new tools and cultural strategies that trendy hunter-gatherers nonetheless use at present. The researchers are utilizing hyrax middens to construct a high-resolution regional local weather historical past for South Africa, the place a workforce of scholars and scientists from throughout the continent can also be re-excavating Boomplaas Cave—one in every of only a few locations with a wealthy archaeological report of people’ transition into the Later Stone Age.
“It is actually a interval the place the lights get turned on when it comes to advanced social and technological habits,” says the workforce’s excavation chief Justin Pargeter, an archaeologist at New York College and the College of Johannesburg. “The behavioral improvements throughout this transition have been extremely profitable. And so they led to our species actually beginning to dominate the ecosystems that they lived in.”
Later Stone Age individuals appear to have began making a precedence of “economizing one thing,” says College of Michigan anthropologist Brian Stewart, who will not be concerned within the analysis. Whether or not restricted by uncooked supplies, time or maybe their software equipment’s weight, individuals of this time started crafting smaller, extra modular stone instruments whose “bladelets” could possibly be swapped out like at present’s replaceable drill bits. Symbolism and social group superior, too: Pargeter notes that Later Stone Age websites are stuffed with beads, which could possibly be used to sign belonging and identification, in addition to ocher, a clay pigment used to color our bodies and add figuring out symbols to things.
The Later Stone Age started within the run-up to the height of the final Ice Age, and lots of researchers assume the interval’s local weather might have contributed to people’ technological and behavioral adjustments. Some suggest that an more and more risky local weather might have compelled our ancestors to get extra inventive at successfully exploiting sources. However that is tough to scrupulously show, significantly as a result of in a lot of Africa the transition started simply past the restrict of radiocarbon relationship—which does not work nicely for samples greater than 50,000 years outdated. With out precisely dated archaeological materials, it is unimaginable to attract clear strains between local weather occasions and know-how.
Boomplaas Cave gives a method round this drawback. The transition out of the Center Stone Age started later there, so the cave’s artifacts are inside attain of correct radiocarbon relationship. And Boomplaas is one in every of few archaeological websites on Earth with a steady report that spans the transition. However researchers right here face one other problem: South Africa’s sparse local weather historical past.
“We do not have conventional archives like ice cores or [cave deposits] and lake data,” says the analysis workforce’s pollen skilled, paleoecologist Lynne Fast of Nelson Mandela College. “So earlier than the hyrax midden stuff, we had very restricted and discontinuous data.”
Most makes an attempt to hyperlink local weather change to the Later Stone Age transition have targeted on measurements from polar ice cores and deep-sea sediments. However these supplies primarily reveal normal, international local weather developments. As with anthropogenic local weather change at present, historical local weather change affected completely different areas in numerous methods. Religion says South Africa’s paleoclimate remains to be so little recognized that it is unclear whether or not the area was dry and harsh or moist and plush on the peak of the final Ice Age.
Staff member Brian Chase, a paleoclimatologist on the College of Montpellier in France, noticed a attainable answer to this puzzle in hyrax middens, the place these small mammals—which seem like rodents however are extra carefully associated to elephants—have dutifully returned to do their enterprise for millennia. Chase has devoted his profession to unlocking these ignored information troves and has collected a whole bunch of samples from southern Africa. “Personally, I feel they’re the most effective paleoenvironmental archives on the planet,” Chase says. “It’s a uniquely wealthy useful resource.”
These middens are “stunning” archives, Stewart says, as a result of they are often radiocarbon-dated together with the close by Later Stone Age transition artifacts. “These are steady data, and that is a tremendous factor to have—similar to the ice cores, however they’re proper subsequent to your website.”
“That is the best way we will truly transfer ahead,” he provides, “as a substitute of creating these sort of wavy pronouncements about what the local weather is doing at a world stage.”
Religion, Chase and Fast sampled middens close to Boomplaas Cave final September and obtained the primary radiocarbon dates from the samples earlier this yr. Combining the persevering with Boomplaas excavations with their unconventional local weather report, the researchers say, gives an actual shot at lastly unraveling the contentious hyperlinks between local weather and technological change within the Later Stone Age—and past.
“There’s this complete different sphere of questions that we’re going to have the ability to soar into by having these big blocks of pee to mess around with,” Religion says. “We hope it’s going to be helpful to lots of people.”
Editor’s Be aware (3/21/23): This text was edited after posting to appropriate the spelling of Justin Pargeter’s title.