The archaeology of the domestic cat

mousers and men

When did cats graduate from convenient pest-control to one of the world’s most popular pets, and how can you tell the difference in the archaeological record? The answer, John Buglass and Jennifer West suggest, may lie in Roman Yorkshire.

Today, the image of a pet cat purring on its owner’s lap is the epitome of cosy domesticity – but this was not always the case. While the archaeological record suggests that dogs staked their claim to being man’s best friend as long as 15,000 years ago (CA 301), felines were much slower in joining our households. But how far can we trace the evolution of this relationship, and how far is it possible to distinguish between cats that coexisted with humans for their own advantage (scavenging our settlements) or for ours (as resident pest control) and those cats that had taken the next step to achieve the status of a beloved pet? Again, archaeology may hold the key.

Pussycat went to sea

Excavations have uncovered cat remains all over the world, but genetic studies suggest that the domestic cat (Felis catus) first emerged as a distinct species from their ancestors, African wildcats (Felis silvestris lybica), in the Near East around 10,000 years ago. Since then they have spread around the world, being transported by humans (knowingly or otherwise) as we explored, traded, and settled. By 7000 BC, we can see evidence of cats cohabiting with humans in China, while some 5,300 years ago they had reached Cyprus – almost certainly introduced by humans, as the island had no indigenous cat population.

The first hints of actual integration with humans came later still, however, from Egypt around 4,000 years ago. This was a culture that revered cats as sacred, but felines also seem to have forged more worldly relationships with humans: an increased cooperation vividly illustrated in 18th Dynasty era (c.1350 BC) murals adorning the tomb chapel of a wealthy official, Nebamun, in Thebes (now on display in the British Museum). Here, a small striped cat is shown helping a hunter to catch or retrieve wild birds, much as we might employ a gundog today. But this is still clearly a working animal, rather than evidence of cats attaining a more sentimental status.

Moving into Europe, cats first appear in ancient Greek art in the 5th and 4th centuries BC – though never as an unambiguous pet – but in the Roman world they are shown in more clearly domestic scenes, including a mischievous moggy helping itself to the contents of a larder, captured in a 1st century AD mosaic from Pompeii’s ‘House of the Faun’. Feline figures feature far less frequently in Roman art than dogs, however, which might suggest that if they were regarded as pets by now, they had not yet attained the heights of popularity that they enjoy today. Once again, few of these depictions allow us to distinguish between resident mousers and members of the family.

Perhaps the most convincing image of a potential pet from this period comes from the Musée d’Aquitaine in Bordeaux, which houses the gravestone of a Gallo-Roman child who died in the 2nd century AD. The stele bears an appealingly lifelike image of a little girl cuddling a cat to her chest. With a childish lack of concern for the animal’s comfort, she grips it under its front legs, leaving its lower body to dangle (and allowing an opportunistic cockerel, perhaps another pet, to seize the tip of its tail in its beak), all the while gazing out at the viewer as if posing for her portrait. An incomplete inscription identifies the girl only as the daughter of a man called Laetus, but it is tempting to fill in the gaps ourselves: might this be a loving depiction of a lost child, shown clutching a pet that she had played with in life?

Cats (and Romans) conquer Britain

Closer to home, our earliest clues to domestic cats in Britain also come mostly from the Roman period (again, much later than dogs, whose remains are known from sites as early as the Mesolithic hunter-gatherer camp at Star Carr, near Scarborough). Although their bones have also been found at a small number of Iron Age sites – notably seven 3rd-century BC skeletons excavated at Gussage All Saints hillfort in Dorset – our best evidence for their being adopted as household animals is found at villa sites like Bishopstone, Lullingstone, and Rudston, as well as in York.

In most of these cases, it once more remains unclear whether these animals were pest control or pets – but one site in the Mid Tees Valley seems more promising. This is a Romano-British villa at Dalton-on-Tees, North Yorkshire, which was first excavated by Teesside Archaeological Society in 1997. Their investigation revealed not only the remains of a substantial villa located beyond what was then accepted as the northern limit of such residences, but also a large and varied assemblage of over 3,700 well-preserved animal bones representing 28 different species. Almost 70% of these remains came from a well that had been backfilled sometime between the 2nd and 4th century AD, and among them were the remains of a small domestic cat.

Even a preliminary examination of its bones could tell that this was one unlucky feline: it had suffered devastating injuries to both the hind- and forelimb on its left side, with the entire head of the left femur missing, and the left elbow showing signs of having been badly broken. The fact that these wounds occur on the same side and – as we will discuss shortly – show similar signs of healing, suggests that they may have been inflicted at the same time, perhaps as a result of being kicked by a larger animal like a horse while hunting for food in a stable, or being hit by the wheel of a cart.

Whatever their cause, there is no doubt that they would have been disabling, potentially fatal injuries – and yet the cat had not died. Extensive new bone growth on both limbs shows clear signs of healing, while ‘polished’ wear patterns on the affected joint surfaces indicate that the limbs had eventually returned to use, albeit with a drastically reduced range of movement. In other words, it appears that a friendly human may have, if not nursed the stricken feline back to health, at least tended it with food and water while its bones knitted back together – a level of care above and beyond what you might expect to be accorded to ‘pest control’ or an opportunistic cohabiter.

Further analysis of the cat’s remains suggests that even after its fractures had healed the animal would no longer have been an effective hunter – one elbow was left partially fused, while its rear limb shows signs of an infection and healed break. Both injuries may (without all of the bones present to compare, we cannot be sure) have left the affected legs shorter than their counterparts.

If this stiff-legged, limping cat, which would certainly not have been able to earn its keep as a working mouser, had been allowed to continue living at the villa rather than being euthanised and replaced, might this suggest that its owner had felt a deeper emotional connection with the animal? If so, this could be our earliest evidence yet in Britain for a cat that was not just a household tool, but a cherished pet.
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Reference:

2016. “The archaeology of the domestic cat”. Current Archaeology. Posted: August 5, 2016. Available online: http://www.archaeology.co.uk/articles/features/archaeology-of-the-domestic-cat.htm

Dogs were domesticated not once, but twice ... in different parts of the world

Man's best friend may have emerged independently from two separate (possibly now extinct) wolf populations that lived on opposite sides of the Eurasian continent

The question, 'Where do domestic dogs come from?', has vexed scholars for a very long time. Some argue that humans first domesticated wolves in Europe, while others claim this happened in Central Asia or China. A new paper, published in Science, suggests that all these claims may be right. Supported by funding from the European Research Council and the Natural Environment Research Council, a large international team of scientists compared genetic data with existing archaeological evidence and show that man's best friend may have emerged independently from two separate (possibly now extinct) wolf populations that lived on opposite sides of the Eurasian continent. This means that dogs may have been domesticated not once, as widely believed, but twice.

A major international research project on dog domestication, led by the University of Oxford, has reconstructed the evolutionary history of dogs by first sequencing the genome (at Trinity College Dublin) of a 4,800-year old medium-sized dog from bone excavated at the Neolithic Passage Tomb of Newgrange, Ireland. The team (including French researchers based in Lyon and at the National Museum of Natural History in Paris*) also obtained mitochondrial DNA from 59 ancient dogs living between 14,000 to 3,000 years ago and then compared them with the genetic signatures of more than 2,500 previously studied modern dogs.

The results of their analyses demonstrate a genetic separation between modern dog populations currently living in East Asia and Europe. Curiously, this population split seems to have taken place after the earliest archaeological evidence for dogs in Europe. The new genetic evidence also shows a population turnover in Europe that appears to have mostly replaced the earliest domestic dog population there, which supports the evidence that there was a later arrival of dogs from elsewhere. Lastly, a review of the archaeological record shows that early dogs appear in both the East and West more than 12,000 years ago, but in Central Asia no earlier than 8,000 years ago.

Combined, these new findings suggest that dogs were first domesticated from geographically separated wolf populations on opposite sides of the Eurasian continent. At some point after their domestication, the eastern dogs dispersed with migrating humans into Europe where they mixed with and mostly replaced the earliest European dogs. Most dogs today are a mixture of both Eastern and Western dogs -- one reason why previous genetic studies have been difficult to interpret.

The international project (which is combining ancient and modern genetic data with detailed morphological and archaeological research) is currently analysing thousands of ancient dogs and wolves to test this new perspective, and to establish the timing and location of the origins of our oldest pet.

Senior author and Director of Palaeo-BARN (the Wellcome Trust Palaeogenomics & Bio-Archaeology Research Network) at Oxford University, Professor Greger Larson, said: 'Animal domestication is a rare thing and a lot of evidence is required to overturn the assumption that it happened just once in any species. Our ancient DNA evidence, combined with the archaeological record of early dogs, suggests that we need to reconsider the number of times dogs were domesticated independently. Maybe the reason there hasn't yet been a consensus about where dogs were domesticated is because everyone has been a little bit right.'

Lead author Dr Laurent Frantz, from the Palaeo-BARN, commented: 'Reconstructing the past from modern DNA is a bit like looking into the history books: you never know whether crucial parts have been erased. Ancient DNA, on the other hand, is like a time machine, and allows us to observe the past directly.'

Senior author Professor Dan Bradley, from Trinity College Dublin, commented: 'The Newgrange dog bone had the best preserved ancient DNA we have ever encountered, giving us prehistoric genome of rare high quality. It is not just a postcard from the past, rather a full package special delivery.'

Professor Keith Dobney, co-author and co-director of the dog domestication project from Liverpool University's Department of Archaeology, Classics and Egyptology, is heartened by these first significant results. 'With the generous collaboration of many colleagues from across the world-sharing ideas, key specimens and their own data -- the genetic and archaeological evidence are now beginning to tell a new coherent story. With so much new and exciting data to come, we will finally be able to uncover the true history of man's best friend.'
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Reference:

EurekAlert. 2016. “Dogs were domesticated not once, but twice ... in different parts of the world”. EurekAlert. Posted: June 2, 2016. Available online: http://www.eurekalert.org/pub_releases/2016-06/uoo-dwd052516.php

Mixed agriculture in northern China developed at similar time to the Near East

An international research team has found the earliest evidence for chicken domestication to date.

Researchers obtained mitochondrial DNA sequences from up to 10,000 year old chicken fossils originating from northern China. At this age, the sequences are several thousands of years older than any other chicken ancient DNA sequences reported previously.

Michi Hofreiter, of the University of Potsdam in Germany and an Honorary Professor in York’s Department of Biology, led the research with Professor Xingbo Zhao from China Agricultural University in Beijing.

Genetic continuity

Despite their age, the northern Chinese chicken sequences already represent the three major groups of mitochondrial DNA sequences present in the modern chicken gene pool, suggesting genetic continuity between these oldest chicken bones known worldwide and modern chicken populations. The research is reported in PNAS.

Based on modern DNA sequences scientists had already suggested that chickens had been domesticated in different places in south and south-east Asia, but previously northern China had never been suggested as a location for chicken domestication.

Different climate and vegetation

Professor Xingbo Zhao said: “People argued that northern China did not provide suitable habitat for red jungle fowl, the wild ancestor of domestic chickens but they do not take into account that climate and vegetation were very different 10,000 years ago.”

The results not only suggest northern China as one of the earliest places for chicken domestication but also that the domestication of chicken, today the most important poultry species in the world, started as early as those of the other four agriculturally important animal species, cattle, pigs, goat and sheep. Moreover, the results provide further evidence for an early agricultural complex in northern China.

Professor Hofreiter, who is also an associate member of the University of York’s Palaeo research centre, added: “These are really exciting results as they suggest that societies with mixed agriculture developed in northern China around the same time they did so in the Near East”.
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2015. “Mixed agriculture in northern China developed at similar time to the Near East”. Past Horizons. Posted: November 25, 2014. Available online: http://www.pasthorizonspr.com/index.php/archives/11/2014/mixed-agriculture-in-northern-china-developed-at-similar-time-to-the-near-east

Modern dog breeds genetically disconnected from ancient ancestors

Cross-breeding of dogs over thousands of years has made it extremely difficult to trace the ancient genetic roots of today's pets, according to a new study led by Durham University.

An international team of scientists analysed data of the genetic make-up of modern-day dogs, alongside an assessment of the global archaeological record of dog remains, and found that modern breeds genetically have little in common with their ancient ancestors.

Dogs were the first domesticated animals and the researchers say their findings will ultimately lead to greater understanding of dogs' origins and the development of early human civilisation.

Although many modern breeds look like those depicted in ancient texts or in Egyptian pyramids, cross-breeding across thousands of years has meant that it is not accurate to label any modern breeds as "ancient", the researchers said.

Breeds such as the Akita, Afghan Hound and Chinese Shar-Pei, which have been classed as "ancient", are no closer to the first domestic dogs than other breeds due to the effects of lots of cross-breeding, the study found.

Other effects on the genetic diversity of domestic dogs include patterns of human movement and the impact on dog population sizes caused by major events, such as the two World Wars, the researchers added.

The findings are published today (Monday May 21) in the scientific journal Proceedings of the National Academy of Sciences USA (PNAS). The Durham-led research team was made up of scientists from a number of universities including Uppsala University, Sweden, and the Broad Institute, in the USA.

In total the researchers analysed genetic data from 1,375 dogs representing 35 breeds. They also looked at data showing genetic samples of wolves, with recent genetic studies suggesting that dogs are exclusively descended from the grey wolf.

Lead author Dr Greger Larson, an evolutionary biologist in Durham University's Department of Archaeology, said the study demonstrated that there is still a lot we do not know about the early history of dog domestication including where, when, and how many times it took place.

Dr Larson added: "We really love our dogs and they have accompanied us across every continent.

"Ironically, the ubiquity of dogs combined with their deep history has obscured their origins and made it difficult for us to know how dogs became man's best friend.

"All dogs have undergone significant amounts of cross-breeding to the point that we have not yet been able to trace all the way back to their very first ancestors."

Several breeds, including Basenjis, Salukis and Dingoes, possess a differing genetic signature, which previous studies have claimed to be evidence for their ancient heritage, the research found.

However the study said that the unique genetic signatures in these dogs was not present because of a direct heritage with ancient dogs. Instead these animals appeared genetically different because they were geographically isolated and were not part of the 19th Century Victorian-initiated Kennel Clubs that blended lineages to create most of the breeds we keep as pets today.

The study also suggested that within the 15,000 year history of dog domestication, keeping dogs as pets only began 2,000 years ago and that until very recently, the vast majority of dogs were used to do specific jobs.

Dr Larson said: "Both the appearance and behaviour of modern breeds would be deeply strange to our ancestors who lived just a few hundred years ago.

"And so far, anyway, studying modern breeds hasn't yet allowed us to understand how, where and when dogs and humans first started this wonderful relationship."

The researchers added that DNA sequencing technology is faster and cheaper than ever and could soon lead to further insights into the domestication and subsequent evolution of dogs.
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References:

EurekAlert. 2012. "Modern dog breeds genetically disconnected from ancient ancestors". EurekAlert. Posted: May 21, 2012. Available online: http://www.eurekalert.org/pub_releases/2012-05/du-mdb051812.php

Humans Tamed Horses All Over the World

The wide origins of domesticated horses offers insight on how our love affair with the animal has transformed humankind.

The domestication of wild horses had a profound effect on human history -- offering nutrition, transportation and a leg up in warfare, among other advantages. But there are still many unanswered questions about when and where our species began its long love affair with horses.

A new genetic study offers some clues. Through the first complete analysis of equestrian mitochondrial DNA -- a kind of genetic material that is passed directly from mother to offspring -- an international group of scientists was able to trace all modern horses to an ancestor that lived about 140,000 years ago.

After horse domestication began about 10,000 years ago, the study also discovered, horses diverged into at least 18 distinct genetic lines. Those findings suggest that, unlike cows and other animals, horses may have been tamed independently in many different places around Europe and Asia.

The new research could help scientists decode the genetic secrets of modern horse breeds and top racehorses.

“Horse domestication had major cultural, socioeconomic, and even genetic implications for the numerous prehistoric and historic human populations that at different times adopted horse breeding,” said Alessandro Achilli, a geneticist at the University of Perugia in Italy. “Thus, our results will have a major impact in many areas of biological science, ranging from the field of animal and conservation genetics to zoology, veterinary science, paleontology, human genetics and anthropology.”

Cows, sheep, and goats had simple beginnings as livestock, with evidence suggesting that a small number of animals of each species were domesticated in just a few places between about 8,000 and 10,000 years ago. Today, genetic diversity among these creatures remains low.

Horse DNA tells a different story, according to a new paper published today in the Proceedings of the National Academy of Sciences. After analyzing mitochondrial DNA from a wide range of horse breeds across Asia, Europe, the Middle East and the Americas, and then using the known mutation rate of this kind of DNA as a sort of clock, Achilli and colleagues were able to connect all modern horses to a common ancestor that lived between 130,000 and 160,000 years ago. By comparison, modern humans first evolved about 200,000 years ago.

Previous research focused only on limited regions of mitochondrial DNA in horses. But by looking at the entire mitochondrial genome, the new study was able to categorize horses into at least 18 different groups that evolved independently.

One possible explanation for those findings is that many different groups of people independently discovered the dramatic benefits of taming wild horses thousands of years ago.

“The very fact that many wild mares have been independently domesticated in different places testifies to how significant horses have been to humankind,” Achilli said. “It means that the ability of taming these animals was badly needed by different groups of people in different regions of Eurasia, from the Asian steppes to Western Europe, since they could generate the food surplus necessary to support the growth of human populations and the capability to expand and adapt into new environments or facilitate transportation.”

Results also showed that horses managed to survive in modern-day Spain and Portugal during a glacial period more than 13,000 years ago, when horses, humans and other mammals disappeared north of the Pyrenees. The area has shown to be an important refuge during that time for people, who later went on to repopulate Europe when conditions improved. The new study suggests that horses may have followed a similar pattern.

The new findings offer another potential explanation for the origins of domesticated horses, said Alan Outram, an archaeologist at the University of Exeter in the United Kingdom. Horses may have been originally domesticated in one area, he said, such as the central Asian steppe. Then, people could have transported tamed stallions to other cultures in other places, where they were bred with local, wild mares. That scenario would also create multiple distinct female genetic lines.

Either way, the new study adds important context to the puzzle of how horses infused themselves into people’s lives.

“One thing that is clear is that the domestic horse revolutionized human life, making us much more mobile, changing our trade patterns and modes of warfare,” Outram said. “Such changes affected the whole way in which societies were organized and interacted with each other.”
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References:

Sohn, Emily. 2012. "Humans Tamed Horses All Over the World". Discovery News. Posted: January 30, 2012. Available online: http://news.discovery.com/animals/horses-domesticated-120130.html

Ancient Dog Skull Shows Early Pet Domestication

33,000-year-old fossil suggests dogs arose in multiple places, study says.

It took 33,000 years, but one Russian dog is finally having its day.

The fossilized remains of a canine found in the 1970s in southern Siberia's Altay Mountains (see map) is the earliest well-preserved pet dog, new research shows.

Dogs—the oldest domesticated animals—are common in the fossil record up to 14,000 years ago. But specimens from before about 26,500 years ago are very rare. This is likely due to the onset of the last glacial maximum, when the ice sheets are at their farthest extent during an ice age.

With such a sparse historical record, scientists have been mostly in the dark as to how and when wolves evolved into dogs, a process that could have happened in about 50 to a hundred years.

"That's why our find is very important—we have a very lucky case," said study co-author Yaroslav Kuzmin, a scientist at the Russian Academy of Sciences in Novosibirsk.

In the case of the Russian specimen, the animal was just on the cusp of becoming a fully domesticated dog when its breed died out.

Dogs Arose at Multiple Sites?

Kuzmin and colleagues recently used radiocarbon dating to examine the skull and jaw of the Russian dog in three independent laboratories. Each lab confirmed the fossil's age at around 33,000 years old.

Burnt twigs also found at the site, known as Razboinichya Cave, suggest that hunter-gatherers used the space for something, and it's likely the dog was their pet before its death from unknown causes, Kuzmin said.

Cold temperatures and nonacidic soil in the cave likely kept the dog's remains from completely decaying, he added.

The team compared the Russian dog fossils with the bones of wild wolves, modern wolves, domesticated dogs, and early doglike canids that lived before 26,500 years ago.

The results showed that the dog—which probably looked like a modern-day Samoyed—most closely resembled fully domesticated dogs from Greenland in size and shape. That's not to say the two dog types are related, though, since the new study didn't run DNA analysis.

Because it wasn't fully domesticated, the Russian dog retained some traits from its ancestors—namely wolf-like teeth. But the animal bore no other resemblance to ancient or modern wolves or to dog breeds from elsewhere in Russia, Kuzmin and colleagues found.

The discovery suggests that this dog began its association with humans independently from other breeds, which would mean that dog domestication didn't have a single place of origin—contrary to some DNA evidence, the study said.

Curious Wolves Went to the Dogs

In general, dogs likely became domesticated when curious wolves began to hang around Stone Age people, who left butchered food remnants littering their camps, according to study co-author Susan Crockford, an anthropologist and zooarchaeologist at the University of Victoria in Canada.

This phenomenon occurred in Europe, the Middle East, and China, according to the study, published July 28 in the journal PLoS ONE.

Animals that were more comfortable around humans underwent changes in their growth rates—probably regulated by hormones—that eventually changed their reproductive patterns, sizes, and shapes, turning them into dogs, Crockford said by email.

For example, dogs became smaller, developed wider skulls, and gave birth to bigger litters than wolves, she said.

"The somewhat curious and less fearful 'first founders' became even more so as they interbred amongst themselves," Crockford said.

Dog Domestication a Chaotic Process

Yet the process of dog domestication in Europe and Asia was chaotic, with many new breeds evolving and then dying out, study co-author Kuzmin noted.

The Russian dog was lost, for example, possibly because the advancing glacial age made hunter-gatherers even more mobile, since they had to range farther to find food.

Some experts have theorized that wolves have to stay in the same place for several decades before they evolve into fully domesticated dogs, Kuzmin said.

Indeed, "domestication is a process as opposed to an event," R. Lee Lyman, an anthropologist at the University of Missouri, Columbia, said by email. "It takes time for sufficient genetic change to occur for a population to evolve from a wild ancestral species into a descendant domestic species."

What's more, "not every evolutionary change is successful in the sense of [a] daughter population diverging from its ancestral lineage and producing a new, distinct lineage or species, domestic or not."

The study, Lyman said, "underscores [these] two important facts that archaeologists sometimes fail to appreciate."
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References:

Dell'Amore, Christine. 2011. "Ancient Dog Skull Shows Early Pet Domestication". National Geographic News. Posted: August 19, 2011. Available online: http://news.nationalgeographic.com/news/2011/08/110819-dogs-wolves-russia-domestication-animals-science-evolution/