Human Use of Fire Earlier Than Thought


Hot Find! Humans Used Fire 1 Million Years Ago

Charles Choi, LiveScience Contributor
Date: 02 April 2012 Time: 03:01 PM ET
Researchers found evidence of human fire use in South Africa's Wonderwerk Cave (shown here), a massive cavern located near the edge of the Kalahari Desert.
Researchers found evidence of human fire use in South Africa’s Wonderwerk Cave (shown here), a massive cavern located near the edge of the Kalahari Desert.
CREDIT: M. Chazan

Ash and charred bone, the earliest known evidence of controlled use of fire, reveal that human ancestors may have used fire a million years ago, a discovery that researchers say will shed light on this major turning point in human evolution.

Scientists analyzed material from Wonderwerk Cave in South Africa, a massive cavern located near the edge of the Kalahari Desert. Previous excavations there had uncovered an extensive record of human occupation.

Microscopic analysis revealed clear evidence of burning, such as plant ash and charred bone fragments. These materials were apparently burned in the cave, as opposed to being carried in there by wind or water, and were found alongside stone tools in a layer dating back about 1 million years. Surface fracturing of ironstone, the kind expected from fires, was also seen.

Micrograph of burned bone on a paleosurface at Wonderwerk Cave in South Africa.
Micrograph of burned bone on a paleosurface at Wonderwerk Cave in South Africa.
CREDIT: Image courtesy of P. Goldberg.

Although modern humans are the only human species alive today, originating about 200,000 years ago, other human species once roamed the Earth, such as Homo erectus, which arose about 1.9 million years ago.

“The analysis pushes the timing for the human use of fire back by 300,000 years, suggesting that human ancestors as early asHomo erectus may have begun using fire as part of their way of life,” said researcher Michael Chazan, a paleolithic archaeologist at the University of Toronto and director of the university’s archaeology center.

The research team’s analysis suggests that materials in the cave were not heated above about 1,300 degrees Fahrenheit (700 degrees Celsius). This is consistent with preliminary findings that grasses, brushes and leaves were burned for these fires — such fuel would not have been capable of hotter flames.

Fire would have helped early humans stay warm and keep nighttime predators at bay, and enabled cooking, which would have made food more digestible. In addition, “socializing around a campfire might actually be an essential aspect of what makes us human,” Chazan said. “The control of fire would have been a major turning point in human evolution.”

Harvard anthropologist Richard Wrangham has speculated that controlled fires and cooked meat even influenced human brain evolution. He suggests that humans were cooking their prey as far back as the first appearance of Homo erectus 1.9 million years ago, just when humans were experiencing major brain expansion, and proposes that cooking allowed our ancestors to evolve larger, more calorie-hungry brains and bodies, and smaller guts suited for more easily digested cooked food.

“It’s possible we may find evidence of fire use as early as Wrangham has suggested,” Chazan told LiveScience.

Future research will analyze both earlier and later materials from this site to see how fire use might have developed over time.

“We’re opening the question of how fire fit into the life of early humans and how that might have changed over time,” Chazan said.

The scientists detailed their findings online April 2 in the journal Proceedings of the National Academy of Sciences.


Can Animals ‘Domesticate” Themselves?

Why some wild animals are becoming nicer

08 February 12

Nature is supposed to be red in tooth and claw, and domestication an artificial process for making animals gentle. But it appears that some corners of the animal kingdom are becoming kinder, gentler places. Certain creatures may be domesticating themselves.

This possibility is most apparent in bonobos, a close cousin of chimpanzees. Unlike their violent cousins, bonobos are generally peaceful. And while many animals have evolved to be socially agreeable, bonobos — and possibly other species –seem to be experiencing something more precise and profound: the physical and behavioural changes specifically described in studies of domestication, but as a natural evolutionary process.

“Normally you think of domestication as something that happens at the hands of humans,” said Brian Hare, a Duke University evolutionary anthropologist and co-author of a bonobo research review published Jan. 20 in Animal Behaviour. “The idea that a species domesticated itself is a bit crazy, but there are some species that outcompeted others by becoming nicer.”

The essence of domestication is a loss of aggression. Because this is such a basic trait, involving modifications to nervous and endocrine systems, and alterations of complex gene networks with multiple functions, it generates a variety of changes. Researchers call them a “domestication syndrome,” and while aspects are seen in all domesticated animals, the principles are distilled in a famous Russian experiment on foxes.

Starting in 1959 with 130 farm-bred but wild foxes and continuing until today, researchers allowed only those individuals most tolerant of human contact to breed. In less than 50 years, the fierce-tempered and untouchable foxes became playful, face-licking sweethearts who loved to be held. Those traits are typically seen in wild pups, but disappear as they grow up.

With juvenile behaviours came juvenile appearances: Even as adults, foxes in the experiment now have spotted coats, floppy ears, curly tails and short legs. They’re evolutionarily suspended in childhood — and that, said Hare, may explain bonobos. “I have a lot of bonobos who are ‘friends,’ and I look at them and say, ‘I don’t understand how you evolved. You are too goofy, too nice, too silly. How did you not get eaten?” he said. “But they are very successful.”

Bonobos are very different than chimpanzees, from whom they split taxonomically about one million years ago. Chimp males struggle constantly and violently for dominance; bonobo males almost never fight, and stage virility contests involving non-confrontational stick-dragging. Male chimps often coerce females into sex; bonobos ask for permission. At the group level, chimpanzees regularly engage in something like low-level warfare, with lethal consequences; bonobos don’t. Mostly they hang out, play, and exchange sexual favors with frequency so astounding they’ve become pop-culture tropes.

Lab tests back up in-the-wild observations. Relative to chimps, bonobos are stressed by competition, attentive to others’ needs, and eager to cooperate and share. Brain regions crucial to behaviour and development, like the amygdala and occipital frontal cortex, are arranged differently. And in keeping with theories of domestication, bonobos play like juvenile chimpanzees, but throughout their lives. Their skulls also have smaller jawbones and teeth, or what anatomists call “paedomorphic” — child-shaped — features. They also have a white tail tuft and extra-pink lips, a possible analogue to the white spots often seen in, for example, cats and dogs.

According to Hare and study co-author Richard Wrangham, one of the world’s foremost primatologists, these are likely signs of domestication. But why and how could natural selection tame the bonobo? One possible narrative begins about 2.5 million years ago, when the last common ancestor of bonobos and chimpanzees lived both north and south of the Zaire River, as did gorillas, their ecological rivals. A massive drought drove gorillas from the south, and they never returned. That last common ancestor suddenly had the southern jungles to themselves.

As a result, competition for resources wouldn’t be as fierce as before. Aggression, such a costly habit, wouldn’t have been so necessary. And whereas a resource-limited environment likely made female alliances rare, as they are in modern chimpanzees, reduced competition would have allowed females to become friends. No longer would males intimidate them and force them into sex. Once reproduction was no longer traumatic, they could afford to be fertile more often, which in turn reduced competition between males.

“If females don’t let you beat them up, why should a male bonobo try to be dominant over all the other males?” said Hare. “In male chimps, it’s very costly to be on top. Often in primate hierarchies, you don’t stay on top very long. Everyone is gunning for you. You’re getting in a lot of fights. If you don’t have to do that, it’s better for everybody.” Chimpanzees had been caught in what Hare called “this terrible cycle, and bonobos have been able to break this cycle.” In doing so, they rose to primate supremacy in a region roughly the size of the United States east of the Mississippi River, and reigned unchallenged until Homo sapiens came along.

All this, at least, is the hypothesis: It’s important to note that it’s a proposed rather than certain scenario. It’s at least conceivable, if highly unlikely, that bonobos started out peaceful and chimpanzees became more aggressive. Conclusive proof would require a time machine. Still, the evidence is suggestive and the scenario plausible.

“High aggression is likely costly,” said Frank Albert, an evolutionary anthropologist at Princeton University who studies the genetics of domestication. “So it seems not very surprising that some of the bonobo-chimp ancestors may have benefited from evolving reduced aggression — and eventually become today’s bonobos.”

Not that bonobos will soon be peeking out of cardboard boxes on Cute Overload. On the trajectory from wild to domestic, they’re something likecertain wolves were tens of thousands of years ago, after reduced aggression allowed them to exploit a new ecological niche at the edges of growing human settlements, said Hare. At that time, people hadn’t yet started keeping and breeding dogs. Once they did, it accelerated a domestication already naturally underway.

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New Light On Human Origins

(These kinds of things just add more questions to the whole question of origins)

African fossils put new spin on human origins story

By Jonathan AmosScience correspondent, BBC News

Professor Chris Stringer, with the help of a cast of a fossil skull, describes the similarities that this species has with modern humans

The ancient remains of two human-like creatures found in South Africa could change the way we view our origins.

The 1.9-million-year-old fossils were first described in 2010, and given the species nameAustralopithecus sediba.

But the team behind the discovery has now come back with a deeper analysis.

It tells Science magazine that features seen in the brain, feet, hands and pelvis of A. sediba all suggest this species was on the direct evolutionary line to us – Homo sapiens.

“We have examined the critical areas of anatomy that have been used consistently for identifying the uniqueness of human beings,” said Professor Lee Berger from the University of the Witwatersrand in Johannesburg

“Any one of these features could have evolved separately, but it is highly unlikely that all of them would have evolved together if A. sediba was not related to our lineage,” the team leader informed BBC News.

A. sediba hand (L.Berger/Uni of Witwatersrand)The female’s right hand is missing only a few bones

It is a big claim and, if correct, would sideline other candidates in the fossil record for which similar assertions have been made in the past.

Theory holds that modern humans can trace a line back to a creature known as Homo erectus which lived more than a million years ago. This animal, according to many palaeoanthropologists, may in turn have had its origins in more primitive hominins, as they are known, such asHomo habilis or Homo rudolfensis.

The contention now made for A. sediba is that, although older than its “rivals”, some of its anatomy and capabilities were more advanced than these younger forms. Put simply, it is a more credible ancestor for H. erectus, Berger’s team claims.

The sediba specimens were unearthed at Malapa in the famous Cradle of Humankind World Heritage Site, just to the northwest of Jo’burg.

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Sleeping with the Chimps

Scientist Snoozes for 6 Nights in Chimp Nests

Stephanie Pappas, LiveScience Senior Writer
Date: 02 September 2011 Time: 10:24 AM ET
Chimpanzees build a new nest every night.


A chimpanzee nest in Kenya.
CREDIT: Joey Verge, under a Creative Commons Attribution 2.0 Generic license

Every night, wild chimpanzees build themselves nests high in the trees and tuck themselves in for a good night’s sleep. But no one knows exactly what makes these nests good sleeping spots for chimps. So biological anthropologist Fiona Stewart decided to find out — by bedding down in the chimp nests herself.

Stewart, a research fellow at the University of Cambridge, found that the shaggy arboreal assemblages in her field site in Tanzania weren’t exactly five-star lodgings, but they did keep hertemperature up and the bug bites down. Sleeping high above ground also eased the anxiety of hearing hyenas call to each other in the East African night.

Stewart “is a very adventurous person,” said William McGrew, Stewart’s former doctoral adviser and a professor of archaeology and anthropology at the University of Cambridge. Her findings could help explain why early humans broke from the chimp tradition of sleeping in trees, McGrew said.

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