What Killed the Neanderthals?

Neanderthals, our closest extinct relatives, roamed the Earth for about 300,000 years. They hunted, made tools, and lived amongst one another in complex social groups. But about 40,000 years ago, they disappeared.

What killed them has been a topic of tense debate for some years. “The issue of Neanderthal extinction is very complex, and very little is agreed upon,” Anna Goldfield, a doctoral candidate in archaeology at Boston University, told LiveScience. Was it climate change? Or a volcanic eruption? One theory even suggests that Neanderthals’ big eyes are to blame for their downfall.

But most researchers agree that modern humans had something to do with it. Indeed, within just 5,000 years of our arrival, Neanderthals had vanished. A new theory suggests that our mastery of fire is the key to why we thrived while they did not. “Fire use would have provided a significant advantage for the human population,” Goldfield said at the annual meeting of the Society for American Archaeology. 

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Aside from keeping us warm, fire allowed us to cook food, which has huge benefits, according to The Economist

“Cooking alters food in three important ways. It breaks starch molecules into more digestible fragments. It ‘denatures’ protein molecules, so that their amino-acid chains unfold and digestive enzymes can attack them more easily. And heat physically softens food. That makes it easier to digest, so even though the stuff is no more calorific, the body uses fewer calories dealing with it.”

It’s not that Neanderthals didn’t use fire — some of them did. Despite their historical portrayal as dimwitted cavemen, these hominids were masters of tool use, and archaeologists think they created sparks by striking flint against iron pyrite. And they did use fire to heat some of their meals. They even cooked with herbs

But Neanderthals may not have made use of flame as regularly or as efficiently as our ancestors did, according to archaeologist Dennis Sandgathe. Early modern human bodies were smaller and more efficient, which meant that cooked food was more beneficial for them. And the more that modern humans utilized the power of flame, “the more likely the human population was to increase slightly.” Over time, this disadvantage may have sealed the Neanderthals' fate.

As archaeologists continue to investigate, we’ll learn more about what really killed off our hominid relatives. “I suspect genetics will help,” says Richard Wrangham, an anthropologist at Harvard. “If we can pin down the genes underlying the adaptation to cooked food, we may be able to date the control of fire close enough to settle the big question.” Either way, the next time you turn your oven on to cook dinner, give thanks to the first modern humans for keeping the fire burning.

The Surprising Reason Why Pen Caps Have Tiny Holes at the Top








[h/t Science Alert]

Mark Ralston/AFP/Getty Images
Big Questions
What Causes Sinkholes?
Mark Ralston/AFP/Getty Images
Mark Ralston/AFP/Getty Images

This week, a sinkhole opened up on the White House lawn—likely the result of excess rainfall on the "legitimate swamp" surrounding the storied building, a geologist told The New York Times. While the event had some suggesting we call for Buffy's help, sinkholes are pretty common. In the past few days alone, cavernous maws in the earth have appeared in Maryland, North Carolina, Tennessee, and of course Florida, home to more sinkholes than any other state.

Sinkholes have gulped down suburban homes, cars, and entire fields in the past. How does the ground just open up like that?

Sinkholes are a simple matter of cause and effect. Urban sinkholes may be directly traced to underground water main breaks or collapsed sewer pipelines, into which city sidewalks crumple in the absence of any structural support. In more rural areas, such catastrophes might be attributed to abandoned mine shafts or salt caverns that can't take the weight anymore. These types of sinkholes are heavily influenced by human action, but most sinkholes are unpredictable, inevitable natural occurrences.

Florida is so prone to sinkholes because it has the misfortune of being built upon a foundation of limestone—solid rock, but the kind that is easily dissolved by acidic rain or groundwater. The karst process, in which the mildly acidic water wears away at fractures in the limestone, leaves empty space where there used to be stone, and even the residue is washed away. Any loose soil, grass, or—for example—luxury condominiums perched atop the hole in the ground aren't left with much support. Just as a house built on a weak foundation is more likely to collapse, the same is true of the ground itself. Gravity eventually takes its toll, aided by natural erosion, and so the hole begins to sink.

About 10 percent of the world's landscape is composed of karst regions. Despite being common, sinkholes' unforeseeable nature serves as proof that the ground beneath our feet may not be as solid as we think.

A version of this story originally ran in 2014.


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