WUSTL

Early man more wary than war-like, new book asserts

Refutes 'natural born killer' model
By Tony Fitzpatrick

Early man was more wary than war-like, more intelligent, agile, and cooperative than aggressive, predator or killer, and he co-evolved as the prey of many species.

The shark and the grizzly bear are two predator species that prey upon humans to this day.

The shark and the grizzly bear are two predator species that prey upon humans to this day.

Moreover, in the old days, woman wore the pants in the family and men were basically expendable, not the brightest bulbs on the tree when it came to tools, and functioning best as sentinels wary of predators in edge environments between the forest and savannah.

Those are the primary themes of a new book, Man the Hunted: Primates, Predators and Human Evolution, co-authored by Robert W. Sussman, Ph.D., professor of anthropology in Arts & Sciences at Washington University in St. Louis, and Donna L. Hart, Ph.D., a member of the faculty of Pierre Laclede Honors College and the Department of Anthropology at the University of Missouri-St. Louis.

Since the process of human evolution is so long and varied, Sussman and Hart decided to focus their research on one specific species, Australopithecus afarensis, which lived between five million and two and a half million years ago and is one of the better known early human species. Most paleontologists agree that Australopithecus afarensis is the common link between fossils that came before and those that came after. It shares dental, cranial and skeletal traits with both. It's also a very well represented species in the fossil record.

According to Sussman, three factors made our forbearer a prime target for a host of predators — small size (adults ranged from around three to five feet and they weighed 60-100 pounds); a total lack of tools or weapons; the inability to use fire.

'Natural born killers'

A sampling of primate fossils found in and near a crowned hawk eagle's nest in east Africa, vivid proof that primates long have been the target of predator species.

A sampling of primate fossils found in and near a crowned hawk eagle's nest in east Africa, vivid proof that primates long have been the target of predator species.

The book rebuts the prevailing popular notion that humans are "natural born killers," genetically programmed to kill, as well as the notion that human males share with chimpanzee males and our common ancestor a killer instinct.

Sussman says that a book published in the late 1990s, Demonic Male, by Richard W. Wrangham, has helped foster notions that humans are inherently violent and hunters first, rather than social beings who evolved that way as a self-defense mechanism.

"These erroneous notions have arisen from observations that, out of many primate species, only humans and chimpanzees will kill their own kind and hunt other mammals," Sussman notes. "The end product is that chimpanzees and humans share genes and biological instincts for killing and that's what makes them good hunters. Our theory says that is all unadulterated garbage. Our reliance upon each other to avoid predators made us survivors. Instead of a need to kill, we developed first the need to cooperate. Group-living mammals need to cooperate to live."

Sussman says that there is absolutely no fossil evidence to support the natural killer scenario. There is, on the other hand, abundant evidence in the fossil record that animals attack and kill primates, from birds of prey millions of years ago to wolves in Europe and crocodiles in Asia today. And, Sussman notes, if you don't think that humans today are not fearful of animal predators, trying yelling "shark!" on a crowded beach.

"Humans are still extremely nervous about predation," he says. "In the book, we look at cats, dogs, birds, reptiles such as crocodiles, even sharks and how they might affect modern primates today and we found that, in nations where there is still lots of natural environment, the predation rate is very high — humans are still preyed upon.

"The main thing that allowed us to survive, and may even had led to our developing language skills, was our counter mechanisms against predators. Early humans had to keep one step ahead of their predators."

Following the female lead

Robert Sussman

Robert Sussman

Sussman and Hart point to a large body of evidence, some old and some recent, that shows females developed and used tools, knew the geography (they remembered where water sources were, but males didn't) chose males as friends that would protect them, and used males as sentinels to protect the group.

"If the females didn't have a male, they would get picked off by predators," he says. "There usually was more than one male in a social group."

The book is illustrated with much fossil evidence, such as an incredible array of primate bones found beneath the nest of a Harpy's Eagle in South America, which, along with Africa's Crowned Eagle and the Phillipine Eagle (formerly the monkey-eating eagle), are the primary birds of prey that to this day are a threat to primates, including humans. There are pictures of Indian men wearing masks on the backs of their heads so that tigers won't attack them, and electrified dummies in agriculture fields to protect the workers from the very real threat of tiger predation.

The predators living at the same time as Australopithecus afarensis were huge and there were 10 times as many as today. There were hyenas as big as bears, as well as saber-toothed cats and many other mega-sized carnivores, reptiles and raptors. Australopithecus afarensis didn't have tools, didn't have big teeth and was three feet tall. He was using his brain, his agility and his social skills to get away from these predators. "He wasn't hunting them," says Sussman. "He was avoiding them at all costs."

Approximately six percent to 10 percent of early humans were preyed upon according to evidence that includes teeth marks on bones, talon marks on skulls and holes in a fossil cranium into which saber tooth cat fangs fit, says Sussman. The predation rate on savannah antelope and certain ground-living monkeys today is around six percent to 10 percent as well.

Sussman and Hart provide evidence that many of our modern human traits, including those of cooperation and socialization, developed as a result of being a prey species and the early human's ability to out-smart the predators. These traits did not result from trying to hunt for prey or kill our competitors, says Sussman.

"One of the main defenses against predators by animals without physical defenses is living in groups," says Sussman. "In fact, all diurnal primates (those active during the day) live in permanent social groups. Most ecologists agree that predation pressure is one of the major adaptive reasons for this group-living. In this way there are more eyes and ears to locate the predators and more individuals to mob them if attacked or to confuse them by scattering. There are a number of reasons that living in groups is beneficial for animals that otherwise would be very prone to being preyed upon."

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