Imagine for a moment you are one of the Skhul-Qafzeh people living in a cave on the slopes of Mt Carmel within sight of the Mediterranean Sea. Each day as you go out to hunt or gather food, at the back of
your mind you’re always aware of the hairy beasts that could attack at any moment. But it is when the sun goes down that you really know you’re prey, because that’s when they are most likely to be out and about.
Darkness is a time to gather the children, huddle together around the fire, listen for the slightest sound, and never—under any circumstances— venture out at night. And this quiet dread is not just for a week or two. It has been going on for as long as anyone can remember. It will be with you until the day you die, as it was with your parents, and theirs—going back to a time before memory. You are prey— food for another species—and these night terrors have become part of your very existence.
If Neanderthal raiding occurred mostly at night, what would be the long-term impact of this on our ancestors? And on us? To answer these questions, fast forward 100,000 years and watch today’s mother put her five-year-old child to bed. Yes, she’ll leave the light on. No, the bogeyman isn’t real. Yes, you’re safe. Now go to sleep.
The contention that modern children have inherited fears from Neanderthal nocturnal predation and that these fears are triggered by darkness is corroborated by a wealth of research on night-time fears in children and adolescents.472 Typically, studies of American children found the fear of monsters and ghosts was reported by 74 percent of children aged 4–6 years, 53 percent of 6–8 year olds, and 55 percent of 10–12 year olds.473 And in a Dutch study of 176 children aged 4–12 years, 73.3 percent of them reported night-time fears.474
The specific nature of these fears appears consistent with the Neanderthal predation hypothesis. A recent Australian study involving 511 children and adolescents aged 8–16 years reports the ten most common night-time fears were:
…fears of intruders/home invasion, noises outside the house, bad dreams, noises inside the house, ghosts, skeletons, witches or spooks, weather noises, worry about daily events, darkness, being alone in the dark, spiders or insects, shadows in the room, and worry about the family’s safety at night.475
This is consistent with several studies that found the most prevalent night-time fears were “bad dreams, nightmares, noises, shadows, monsters, intruders, burglars, kidnappers, and of being left alone at night”.476
Among older children (7 to 13-year-olds) fear of the dark and fear of a burglar breaking into the house were among the most cited fears.477
My modelling based on NP theory predicts that young Levantine pubertal females were the major focus of Neanderthal sexual raiding. This predicts that night-time fears among modern children will be more pronounced in girls than boys. This prediction is corroborated by research data. All the studies report that girls have more night-time fears and frightening dreams than boys (72.9 percent compared to 54.6 percent males).478,479
Obviously, it’s impossible to say for certain that a child’s night-time fears originate from traumatic events that occurred up to 100,000 years ago. But the association of night-time, imaginary creatures, invasions and abductions reported by children is consistent with an innate adaptive response to nocturnal predation in our evolutionary past.
Unfortunately, while there is copious literature on childhood fears, very little research has been conducted on nyctophobia (fear of the dark) in adults—and almost no cross-cultural data is available on this subject. Anecdotal first-contact reports claim Indigenous Australians never ventured from their camps after dark for fear of encountering evil spirits, and many hunter-gatherer societies report a fear of the dark, but apart from that there is almost nothing—certainly not enough to test the theory that modern humans are innately apprehensive of the dark and that low-level predation anxiety remains the primary cause of human insomnia. Clearly more cross-cultural research is needed.
For all prey species subject to nocturnal predation, getting enough sleep is a major issue that directly affects survival.
Each species acquires its own specific adaptations unique to its predators, habitat and sleep requirements. One solution is to limit the time spent asleep. While predators like lions sleep up to 17 hours a day, the hoofed animals they hunt have adapted to only a few hours sleep, and mostly on their feet. Giraffes for example, sleep less than two hours a day.
Another common solution is to find a safe place to sleep away from predators. Rabbits, moles, snakes and wombats retreat to deep burrows where they’re usually safe, while bats that live in caves can sleep up to 19 hours a day.
Some species of birds, seals, manatees, whales and dolphins have acquired the ability to literally sleep with one eye open, (unihemispheric slow-wave-sleep) allowing them to be constantly alert for predators.480
This adaptation required the rewiring of their brains into two separate hemispheres, each able to operate while the other is offline. EEG readings from the brains of ducks show that half their brain sleeps while the other half remains in a mid state between alertness and light sleep. And when they sleep in a group, those on the outside, (where the risk of predation is higher) sleep with one eye open nearly 32 percent of the time, compared with only about 12 percent of the time for those on the inside.481
Chimps climb trees each night and build sleeping nests out of leaves— which is probably what African hominids did too. That is, until they discovered the art of fire-making about 750,000 years ago. Fire provided a new level of protection against nocturnal predators, its light keeping leopards, wolves and other nocturnal carnivores at bay and allowing our ancestors to sleep in relative peace for the first time.
During the Neanderthal predation, however, fire lost is protectiveness. The ingenious invention that protected hominids from the most savage carnivores would be useless against Neanderthals because they used fire themselves.
So how did our Levantine ancestors cope? I suggest that, as well as learning to fear the dark and not venturing out at night, our ancestors evolved at least two species-specific adaptations to the problem of sleep and security. The first required inventing a new kind of sleep.
Given that the brains of some prey species have evolved specialist neuronal networks to maintain vigilance for nocturnal predators while they sleep, it is interesting to find that human sleep is not constant throughout the night. It varies between periods of light and deep sleep. These variations are called sleep cycles, and they occur about every 90 minutes. Normally, we each experience between three to six cycles every night.
Each individual cycle is broken up into four stages. Stages one and two are considered light sleep and stages three and four signify deep sleep. During light sleep, a person is still responsive to sounds and movements and can be easily woken. This is because during light sleep, the sensory organs maintain communications with the amygdala—the part of the brain that monitors for threats, including Neanderthals. What’s more, in the light stages of sleep, your muscles are not immobilised so if you have to move suddenly, you can. Light sleep is really a half-awake state.
Why we have this cycle of light and deep sleep has never been explained. Despite mountains of research into sleep, researchers still have no idea why the cycle evolved or what function it serves. However, the unique oscillating sleep cycle, with its characteristic period of light sleep may be the human equivalent of a bird’s hemispherical sleep.
At first, the light-deep sleep cycle may not seem like an adaptive solution to the problem of getting a good night’s rest during the Late Pleistocene. But the ingenious simplicity of this solution becomes clear when you realise that the Skhul-Qafzeh humans were part of a primate lineage that traditionally lived and slept in groups, or troops.
Although Westerners abandoned communal sleep around the time of the Industrial Revolution, communal sleeping had been the norm for literally millions of years. So, with ten or more people sleeping together in the same cave, or around the same campfire, there would always be at least one person in a light stage of sleep. Someone in the group would always be half awake and able to respond to strange sounds or movements, and could quickly rouse the others if they sensed Neanderthals were sneaking up on them.
As a nocturnal sentinel system, a 90-minute sleep cycle would be most ef- fective on quiet, windless nights when the sound of approaching Neanderthals could easily be heard. But, unlike other animal predators, Neanderthals had roughly the same level of intelligence as humans and were probably cunning enough to counter this. Approaching on a windy night, or during a storm, when their sound and scent were diffused by the environment, they could possibly have got close enough before the alarm was sounded. Despite unique sleep cycles providing a degree of protection against nocturnal attacks, the hours between dusk and dawn almost certainly remained the most dangerous period in our ancestors’ lives.
In the absence of burglar alarms, police, armies or sentries, what other remedies against nocturnal predation would have been available to our ancestors? I suggest the only thing that was within the realm of possibility in the Late Pleistocene, was a canine sentry. Our ancestors needed a guard dog.
With exceptional night vision and a nose that can detect scents one hundred times fainter than those humans can, dogs can detect intruders long before any human, making them ideal nocturnal camp guards. Even today, the sound of a dog barking in the dark can cause a primal frisson and alert you to a potential threat. The use of dogs as nocturnal guards throughout history, their universal appearance in world myths as guardians and gatekeepers, our instinctive affection for them, and the way they segue perfectly into a theoretical survival strategy suggests strongly that they played an important role in human evolution.
It’s easy to see how this relationship started. Wolves would have been attracted to human camps to scavenge food. This probably suited the humans because it got rid of rotting meat and carcasses. Early human children may have taken in wolf cubs simply because they were cuddly and cute. The tamest of these would be kept as pets and bred. Once humans realised the tame wolves could smell Neanderthals and raise the alarm, the bond was formed.
To test this hypothesis, we need to remember that Neanderthal predation began between 100,000 and 110,000 years ago, which means that humans established canids as guard dogs roughly around this time. Is there any proof of this?
Egyptians hieroglyphics portrayed dogs, including different breeds that appear similar to today’s greyhounds and mastiffs, but these hieroglyphics date only to about 6000 years ago. The earliest pictorial representation of dogs found anywhere come from a Spanish cave and is about 12,000 years old, which is also the date of the earliest human-dog burial in Israel.482
Until very recently, the fossil record shows that humans started to domesticate and interbreed dogs only about 15,000 years ago. Although these animals looked like wolves, they show slight physical differences.
The remains of one of these proto-dogs (dated at 14,000 years ago)483 was found at Oberkassel in Germany, while another has been dated to between 10,000 to 15,000 years ago.484
Half the lower jawbone of a dog was also discovered in the Palgawra cave in north-eastern Iraq (part of the Levant) and radiocarbon dated at a minimum of 12,000 years old.485 Although this fragment has often been held up as the first real proof of a domesticated dog, it’s a bit risky making these kinds of assumptions on the basis of a three inch piece of bone and a few molars. Nevertheless, slight changes in the teeth and facial structures of wolf remains have been interpreted as evidence of a relationship between humans and canids, which in turn indicates domestication.486
This would indicate the wolves whose skulls were found in a 24,000 year old mammoth hunting camp in the Ukraine, with foreshortened muzzles, smaller teeth and dental crowding, had been domesticated. But that is considerably short of our 100,000–110,000 year target.
As recently as October 2008, a team of European archaeologists announced they had unearthed over a hundred fragments of ancient dog remains from sites in Russia, Belgium and the Ukraine. The researchers, led by palaeontologist Mietje Germonpré from the Royal Belgian Institute of Natural Sciences reported that one Belgian skull was 31,700 years old, and was “clearly different from the recent wolves, resembling most closely the prehistoric dogs”.487 Their analysis of the material led them to conclude these were the skulls of domesticated dogs.
While this latest finding pushes back the date of domestication to almost 32,000 years ago (when Neanderthals still lived in Europe) the dates nevertheless appear to challenge the proposition that dogs were used during the period of Neanderthal predation in the Levant . However, the proposal is not that Skhul-Qafzeh humans used modern dogs to guard their camps. It is that they used domesticated wolves as guard dogs.
A number of studies from different disciplines; (behaviour, morphology, vocalisations and genetics) all show that modern dogs are descended from the wolf, canis lupus. The 400 odd breeds of modern dogs are so closely related to their single common ancestor that, from the massive Saint Bernard and Irish wolf hounds to the diminutive Chihuahua, their mitochondrial DNA varies at most by 0.2 percent from the wolf.488
Unlike the dog, grey wolves have been around for at least 300,000 years489. They have exceptional hearing and sense of smell—and wolf fossils are found in ancient human sites.
The burgeoning science of molecular genetics, which allows species to be traced via their DNA has provided some startling new dates that have a bearing on this issue. In June 1997, a seminal paper ‘Multiple and Ancient Origins of the Domestic Dog’, by a leading expert on the origins of dogs Robert Wayne and others, was published in Science.490 The geneticists analysed mitochondrial DNA taken from 162 wolves at 27 locations around the world.
MITOCHONDRIAL DNA
Mitochondrial DNA (mtDNA) are molecules that act as a kind of fuel cell for the main DNA by converting nutrients into energy that cells can use. In humans, mtDNA is inherited from the mother’s side. Over the last decade or so, geneticists have been able to extract mtDNA from ancient fossils, including human bones.
Because wild dogs can interbreed, the geneticists also included DNA samples from coyotes and jackals. They then compared these sequences with mtDNA from 140 domestic dogs (representing 67 breeds and 5 cross- breeds from Europe, Asia and North America) to determine the degree of genetic variation. The idea was to calculate precisely when dogs first departed from their wolf ancestors. The findings confirmed an earlier hypothesis by the authors, that dogs were descended from wolves.
But the most startling find was yet to come. The DNA analysis traced various dog breeds into several ‘clades’—segments that evolved from common ancestors. Clade 1, for example, “contained representatives of many common breeds as well as ancient breeds such as the dingo, New Guinea singing dog, African basenji, and greyhound”. The scientists then analysed the divergence within each clade. The degree of divergence between wolves and coyotes reveal they separated about one million years ago. But most significantly, according to Wayne and his co-authors, the divergence between the dogs in clade 1 “implies that dogs could have originated as much as 135,000 years ago”.
Although the study warns that such estimates may be inflated slightly by the techniques used, Wayne notes, “the sequence divergence within clade 1 clearly implies an origin more ancient than the 14,000 years before the present suggested by the archaeological record”. When all the factors were considered, Wayne concludes that the mtDNA evidence “suggested that dogs originated more than 100,000 years before the present”.
In effect, the DNA evidence reveals that wolves were first ‘modified’ by contact with humans at least 100,000 years ago, which coincides with the hypothesis that Skhul-Qafzeh humans first raised wolf cubs 100,000–110,000 years ago and used them as guard dogs.
If domesticated wolves and proto-dogs provided humans with this vital protection during those fraught early years, then we probably partly owe our survival as a species to them. That may account for the special bond that exists between humans and dogs. And it would demand a new recognition of the extraordinary role they played in our survival. It explains why dogs really are man’s best friend.