April 4, 2012
Discussions of fire and human evolution conjure up images of cavemen sitting around a campfire roasting chunks of meat on sticks. But who were the first “cavemen” to do this? Debate goes back and forth between anthropologists who claim hominids began controlling fire nearly two million years ago and those who think our ancestors started stoking flames only a few hundred thousand years ago.
Now a new study of one-million-year-old charred bones and plant remains provides the earliest “secure” evidence of hominid fire-making, researchers say.
The new evidence comes from South Africa’s Wonderwerk Cave. Archaeological investigations there in the 1970s through 1990s turned up Acheulean tools—stone handaxes and other implements that were likely produced by Homo erectus. In 2004, Francesco Berna of Boston University and his colleagues began new excavations. They found several signs of fire, including tiny charred bone fragments and ash from burned plants. They also found ironstone—which the hominids used to make tools—with telltale fractures indicative of heating. Using a technique called Fourier transform infrared microspectroscopy, which examines how a sample absorbs different wavelengths of infrared light, the team determined the remains had been heated to more than 900 degrees Fahrenheit, with grasses, leaves or brush used as fuel.
The shape of the bone fragments and the exceptional preservation of the plant ash suggest the materials were burned in the cave—not outside and then transported in by water, the team reports this week in Proceedings of the National Academy of Sciences. Spontaneous combustion of bat guano was also ruled out (apparently this sometimes happens in caves). That left hominids as the most likely source of the fire.
This is good news for Harvard University’s Richard Wrangham and supporters of his cooking hypothesis. According to Wrangham, mastering fire was a transformative event in the history of humans. It allowed our ancestors to cook. And because cooked food is easier to digest, the hominid gut shrank, freeing up energy that was then devoted to fueling the evolution of bigger brains, which are very expensive to maintain, energetically speaking. (Brain tissue needs 22 times as much energy as an equivalent amount of muscle.)
Wrangham surmised this important transition must have occurred with the origin of Homo erectus, some 1.9 million years ago, when brain size really began to expand and the hominid body became taller and more modern.
The fire at Wonderwerk is too young to fully support Wrangham’s hypothesis, but it’s a step in the right direction. Previously, the earliest well-accepted instance of fire-building came from Israel’s Qesem Cave at 400,000 years ago. For claims of much older examples of controlled fire, such as at a 1.5-million-year-old Kenyan site called Koobi Fora, wildfires couldn’t be ruled out.
If the history of fire extends back one million years, why don’t archaeologists find more evidence of it? Last year, for example, Wil Roebroeks of Leiden University in the Netherlands and Paola Villa of the University of Colorado Museum in Boulder surveyed the European archaeological record of the last 1.7 million years. They didn’t find habitual use of fire until about 400,000 years ago, they reported in Proceedings of the National Academy of Sciences, leading them to conclude hominids must have colonized the northern latitudes without fire’s warmth.
Berna’s team thinks the problem might be in how archaeologists have been looking for fire. The new research involved examining the cave sediments, bones and plant ash at a microscopic level, which revealed information that’s normally overlooked. Perhaps with the help of such microscopic methods, anthropologists will find that the origin of fire is indeed linked to the origin of Homo erectus.
December 21, 2011
This week Smithsonian introduced the concept of “evotourism,” with 12 sites around the world where visitors can appreciate and learn about evolution. One stop on the tour relates to human evolution: South Africa’s Cradle of Humankind, where the first Australopithecus fossils were discovered.
But there are many other locations where evotourists can marvel at the science and history of human evolution. Here are five additional hominid evotourism destinations.
1. Olduvai Gorge, Tanzania
Its place in hominid history: Some 2,000 miles northeast of the Cradle of Humankind is Africa’s other self-proclaimed Cradle of Mankind, Olduvai Gorge, made famous by Louis and Mary Leakey. In 1959, the husband-and-wife team uncovered a 1.75-million-year-old skull belonging to a species of hominid they dubbed Zinjanthropus boisei, now called Paranthropus boisei. The finding shifted hominid hunters’ interest from South Africa to East Africa, where paleoanthropologists have since found some of the earliest hominids. In the early 1960s, the Leakeys discovered another hominid that once lived at the site, Homo habilis. Dating to about 2.5 million years ago, this species is the earliest known member of the genus Homo. Although it still retained some primitive features, it was the first hominid to have a brain larger than an ape’s. The species’ name means “Handy Man,” referring to the Leakeys’ belief that this hominid made the numerous stone tools found at Olduvai Gorge. These tools are significant in their own right. They are some of the oldest stone tools ever found, and today, archaeologists refer to these types of tools as Oldowan.
What to do there: After touring the Olduvai Gorge Museum, visitors can take guided walks of the hominid site. But the area offers more than just fossils and impressive vistas. The gorge is located within the protected Ngorongoro Conservation Area. The Ngorongoro Crater, the area’s namesake, is a collapsed volcanic crater carpeted with the grasslands of the Serengeti. Tourists can join walking or vehicle safaris, with the chance to glimpse some of the Serengeti’s most famous residents, including lions, baboons, zebras, wildebeest and flamingos.
2. Sangiran, Indonesia
Its place in hominid history: In the 1890s, Dutch anatomist Eugene Dubois discovered the first fossils of Homo erectus (at the time, the species was known as Pithecanthropus erectus), on the island of Java. In fact, it was among the earliest discoveries in the fledgling field of paleoanthropology. Based on the features of the fossils—a modern-looking thigh bone indicating upright walking and a primitive skull cap with thick brow ridges and a sloping forehead—Dubois believed this so-called Java Man was an intermediate form between apes and humans. Starting in the 1930s, German anthropologist Gustav Heinrich Ralph von Koenigswald excavated at Sangiran, not far from where Dubois conducted his work. Von Koenigswald found additional fossils as well as stone tools. These sites in Java, dating to more than a million years ago, are some of the oldest hominid fossil locales outside of Africa.
What to do there: Located in Central Java, about 15 miles south of the city of Solo, Sangiran is a Unesco World Heritage site. The Sangiran Museum offers displays of Java Man fossil replicas as well as real fossils of animals that lived in the area 1.2 million to 500,000 years ago. Tourists can also visit the Sangiran archaeological site, where fossils are still being unearthed, and climb a three-story observation tower to get a more expansive view of the region.
For more information, visit Indonesia’s Official Tourism Website.
3. Zhoukoudian, China
Its place in hominid history: The first and oldest hominid fossils discovered in East Asia were found in the 1920s by paleontologists working at the caves of Zhoukoudian, or Dragon Bone Hill, about 30 miles southwest of Beijing. The fossils were assigned to the species Sinanthropus pekinensis, colloquially called Peking Man. Eventually, anthropologists realized the Sinanthropus fossils in China and the Pithecanthropus fossils in Java belonged to the same species, Homo erectus. The original fossils found in the 1920s through 1930s went missing during World War II, but researchers have since found dozens of other fossils and stone tools. The site is also home to early evidence of the use of fire.
What to do there: With its close proximity to Beijing, Zhoukoudian is easier to get to than many of the other sites on this list, accessible by car or bus. Once there, visitors can see hominid fossils on display at the Zhoukoudian Anthropological Museum, along with the fossils of other animals that coexisted with Peking Man. Tourists can also visit the caves where excavations took place.
4. Lake Mungo, Australia
Its place in hominid history: Located more than 300 miles north of Melbourne, the now-dry Lake Mungo is home to Australia’s oldest human remains. In 1968, geologist Jim Bowler and a group of archaeologists discovered the burnt bones of a woman; six years later, Bowler found the skeleton of an adult man. Known as Mungo Lady and Mungo Man, the fossils have been the center of much debate, with dates for the pair ranging from 28,000 to 62,000 years ago. Today, researchers in Australia think the Mungo people lived about 40,000 years ago—evidence that modern humans arrived in Australia at a very early date. More recently, in 2003, scientists unearthed 500 footprints left behind by humans, other mammals and birds 20,000 years ago.
What to do there: Mungo National Park offers visitors a variety of ways to explore the area’s dry lake beds, sand dunes and grasslands: short hikes, longer driving and bike paths, and tours led by aboriginal park rangers. The park’s visitor’s center has exhibits on the region’s natural history and cultural heritage, and the outdoor Meeting Place has a recreation of the park’s ancient footprints (the real footprints have been covered for their protection and preservation). Several other national parks are within a few hours’ drive of Mungo.
For more information, visit the Mungo National Park website.
5. Lascaux Caves, France
Its place in hominid history: The Vézère Valley in southwestern France is home to 147 archaeological sites and 25 caves adorned with ancient paintings. The most famous cave paintings are those of Lascaux, discovered by a group of teenagers in 1940. The cave paintings depict 100 animal figures, including bison and horses, as well as some human figures.
What to do there: Sadly, tourism has damaged the Lascaux caves paintings. The site opened to the public in 1948, but the arrival of people also brought bacteria, fungi and other microbes that have led to the deterioration of the cave art, and the caves are now closed to the public. However, visitors can tour a replica of the cave and its paintings nearby at Lascaux II. Perhaps an even less intrusive way to see the paintings is through an online virtual tour.
For more information, visit the Lascaux Cave website.
These are just a few accessible locations important to the study of hominid history. What stops would you add to the human evolution world tour? And which would you most like to visit?
December 19, 2011
Anthropologists have suggested early Homo was a meat-and-potatoes kind of hominid. Starting roughly 2.5 million years ago, early species of Homo were the first hominids to have brains bigger than an ape’s. But brains are expensive, metabolically speaking. To fuel their added brain power, these hominids probably introduced new energy-rich foods to their diet. Researchers have long pointed to meat as the critical food that allowed for this initial brain expansion; after all, stone tools useful for hunting and butchering appear in the archaeological record at this time. More recently, the significance of underground tubers has been highlighted. But another crucial food may have been honey. Alyssa Crittenden, a behavioral ecologist and nutritional anthropologist at the University of Nevada, Las Vegas, makes the case for the sweet liquid’s importance in the journal Food and Foodways.
Honey has several qualities that make it a super food, Crittenden points out. It’s very energy dense, about 80 to 95 percent sugar, and it’s a good source of the glucose needed to nurture brain development. Wild honey also contains traces of bee larvae, adding fat, protein, vitamins and minerals. And on top of that, it’s easy to digest. The nutritional benefits of honey are clear, but there is no concrete evidence in the fossil record of hominids eating honey; honey consumption doesn’t leave behind the kind of scraps that can fossilize the way that hunting and butchering does. So Crittenden relies on some indirect clues to bolster her argument.
First, the significance of honey to human evolution may be inferred from the fact that the sugary liquid is an important dietary staple for people around the world. In Paraguay, for example, the Ache believe honey is the second most important food in their diet, after game meat; honey can provide an Ache with more than 1,100 calories per day. Honey can constitute 80 percent of the calories consumed by the Efe pygmy people of the Congo and 15 percent of the diet of the Hadza of Tanzania. Furthermore, people go to great lengths to get honey. The Hadza often follow honeyguide birds to hives of stinging bees. The honey hunters then burn brush near the entrance of the beehive to smoke out the bees, who become confused and disarmed by the smoke. In Nepal, honey collectors climb bamboo ladders positioned on cliff faces to access nests tucked away in crevices. Ancient art verifies that honey consumption is not a recent phenomenon. Rock art depicting honeycombs, swarms of bees and honey collecting date to as many as 40,000 years ago. Such art has been found in Africa, Europe, Asia and Australia.
Our primate cousins are another line of evidence. A variety of monkeys and apes eat honey today. Baboons and macaques, for example, use their hands and mouths to harvest honey from the nests of stingless bees. Orangutans, gorillas and chimpanzees also like honey and bee larvae, often using sticks to extract the food from hives. If these primates are able to procure honey, Crittenden says, “it is highly likely that early hominids were at least as capable of honey collection.” Like modern apes, australopithecines may have used sticks to retrieve honey. Honey may have become a larger component of the diet with the invention of stone tools, which would have allowed our ancestors to more easily open beehives, Crittenden says. “Their success rates would have skyrocketed.” Later, exactly when is debatable, mastering fire may have allowed hominids to smoke out stinging bees, as modern people do, making it even easier to collect honey.
Although Crittenden thinks honey was a critical food that allowed for brain expansion, she acknowledges it wasn’t the only food. Our ancestors were omnivores, she says. Meat, tubers, honey—and perhaps other foods—all helped hominids evolve their most notable feature.