Where Do Cats Come From?
By Claudio Ottoni
Pest-control agent, object and symbol of value in past civilizations, companion animal, and Internet celebrity, the cat has long held a unique position in our collective consciousness. Across the centuries, cats have accompanied people all over the world along trade routes. There are currently more than 1.2 billion feral and pet cats across all continents except Antarctica. But where do they come from?
Cats are enigmatic domesticates. They were not primarily exploited for their economic or subsistence value and the paucity of cat remains in the archaeological record has long hampered a systematic and complementary approach to the study of cat domestication. Cats were attracted to human settlements as scavengers or following the arrival of anthropogenic commensal rodents (rats and mice). Humans appreciated the presence of cats as they kept pests under control and in turn cats had easier access to food sources available around human settlements.
Neolithic cat skeleton buried near its human. Shillourokambos, Cyprus. http://www.chinadaily.com.cn/english/doc/2004-04/09/content_322064.htm
This so-called 'commensal' relationship most likely started 10,000 years ago in the first sedentary human communities growing cereals in the Near East, in particular in the Levant. The presence of cat remains in Neolithic contexts of Cyprus, where there is no evidence of native felid species, and in particular a complete skeleton found in in association with a human burial dated to around 9,500 years ago, indicates that cats travelled with farming communities to the Eastern Mediterranean islands, and that they established a quite intimate and strong bond.
Besides the evidence from the Levant, a key source of information about the origins of cat-human relationship comes from Egypt. Figurative art and iconographic depictions (including the popular "cat under the chair" motif) of Pharaonic Egypt was the longstanding source of the belief that cats were domesticated in Egypt. Zooarchaeological evidence of cat taming from an elite Predynastic cemetery suggests that the relationship between cats and humans in Egypt may have started as early as 5,700 years ago.
Cat under the chair. Tomb of Nakht at Thebes. New Kingdom Ashmolean Museum.
The paleogenetics of cat dispersal.
Recently, the analysis of the DNA contained in bones, teeth, claws and even hairs of more that 200 ancient cat specimens – a study conducted by the University of Leuven, the Royal Belgian Institute of Natural Sciences of Brussels and the Institute Jacques Monod of Paris – has shed new light on the history of cat domestication. Through cutting-edge ancient DNA techniques, we investigated the maternal ancestries (the maternally inherited mitochondrial DNA) of cats from various archaeological sites in Europe, Southwest Asia and Africa. The temporal depth and the geographic coverage of the samples made it possible to infer the original phylogeographic structure of cats (i.e. the geographic distribution of genetically distinct cat populations in the past), something that archaeological surveys and genetic analyses of modern cats could not detect.
Mummified cat. Image courtesy of Claudio Ottoni.
Extracting samples for DNA testing. Image courtesy of Claudio Ottoni.
The study revealed that F. s. lybica, the ancestor of all modern domestic cats in Northern Africa and the Near East, was already present in southeast Europe 10,000 years ago – prior the arrival of farming communities in Europe during the Neolithic – and was distributed in the Anatolian peninsula since at least the Neolithic. However, two distinct F. s. lybica genetic lineages were present on the two sides of the Bosporus, and about 6,400 years ago cats carrying the Anatolian (and general Near Eastern) lineage appeared in late Neolithic contexts of southeast Europe. This suggests that the human-mediated movement of cats began in prehistoric times, corroborating the interpretation of the 9,500 year-old cat in Cyprus. However, compared to other animal domesticates, cats were introduced to southeast Europe by farming communities at a later stage of the Neolithic.
Spatio-temporal representation of cat maternal genealogies. From C. Ottoni et al. The palaeogenetics of cat dispersal in the ancient world. Nature Ecology & Evolution. Volume 1, Article number: 0139 (2017)
A second, more relevant cat dispersal occurred during the Classical and Roman era, when a genetic lineage of African distribution detected in ancient cats from Egypt appeared in coastal sites of Turkey and in southeast Europe. Cats in Egypt were worshipped and during the Greco–Roman period, kept in temple precincts to be mummified. They were at total ease in domestic contexts, as witnessed by the depiction of the 'cat under the chair' theme, and the peculiar social and cultural context of the Egyptian society may have facilitated the evolution of a more tolerant disposition of cats towards humans. From pest-control agents in farming communities, in the Egyptian households cats probably turned into the companions that we know today. The increasing popularity of cats among Mediterranean cultures (e.g., the Phoenicians, Carthaginians, Greeks, Etruscans, and Romans) and their usefulness on ships infested with rodents and other pests presumably sparked their dispersal across the Mediterranean from Egypt.
North of the Alps, domestic cats appeared soon after the Roman conquest, yet remained absent outside the Roman territory until Late Antiquity. Further expansion took place in the Middle Ages, when it was compulsory for seafarers to have cats on board to safeguard food, ropes and leather material from rodents and other pests. Cats carrying the Egyptian genetic lineage were even found at the Viking port of Ralswiek, in Northern Europe.
The phylogeographic picture that we recomposed through the genetic lineages of ancient cats seemed to track the main routes of human trade over the Classical, Roman and Medieval era, and the trajectories of connectivity crossed the borders of the Mediterranean as we observed lineages belonging to cats from Asia (F. s. ornata) in the Roman port-site of Berenike, in the Red Sea coast of Egypt, and in two coastal Turkish sites. This was probably the result of intensive and direct trade connections between south Asia and the Mediterranean basin via the Indian Ocean and Red Sea, but possibly also via the Silk Road connecting central Asia with Anatolia.
Selection and human intervention during cat domestication.
While the maternal lineages of the mitochondrial DNA of ancient cats allowed us to track the routes of human-mediated dispersal, the study of a mutation in a nuclear gene added more insights on the coat colour pattern of ancient cats, in particular whether they possessed blotched or mackerel tabby markings. The tabby phenotype is common in both wild and domestic cats, but the two variants, mackerel and blotched, distinguish respectively wild and domestic populations. The investigation of this phenotypic trait in the ancient cats that we analysed showed that the first occurrence of the mutation that causes the blotched tabby marking dates to the Ottoman Empire in Southwest Asia, and later increases in frequency in Europe, Southwest Asia and Africa. This suggests that selection for coat color (and most likely human-mediated breeding activity) occurred rather late in the history of cat domestication, as opposed to other domesticates like horses.
Importantly, cats were never selected for a peculiar task by humans; they already possessed in their wild state the predatory skills that made them useful to human communities: hunting mice and other pests that infested human grain storages (or households, ships and so on). In the behavioural context of the Egyptian society cats developed a more tolerant attitude towards humans and became their companions, while maintaining their innate predatory skills and a sort of aloofness that is still a landmark of modern housecats. This is corroborated by the analysis of full genomes in modern cats, which recently suggested that the main differences between wild and domestic cats are at the level of behavioural traits.
On the contrary, most other domestic animals followed a pathway of domestication that at some point was strongly influenced by human manipulation aimed at selecting specific traits that could assist humans (for example for work or for food supply). This is true for livestock species, horses and also for the dog. The dog was the first animal to be domesticated. The extreme variation in size and shape we observe in domestic dogs stems from the fact that humans for a long time selected them to assist for specific tasks such as hunting, protection, and sled-pulling. Artificial selection (hence, targeted human manipulation) was introduced in cat domestication only very recently, in the 19th century, without any objective to select peculiar skills, except for generating 'visible' variation. This selection affected mostly the coat variation, not much the body shape and size, and led to the origin of most of the actual 'fancy' breeds.
Our ancient DNA study provides answers to longstanding questions concerning the domestication process of the cat, revealing that both Near Eastern and Egyptian cat lineages contributed at different times to the maternal genetic pool of domestic cats. However, cat domestication remains a complex, long-term and quite unconventional process (one may even argue that the cat is not actually domesticated) featuring extensive translocations that allowed admixture events between geographically separated cat populations at different points in time. In the future, the analysis of full ancient genomes will help to pinpoint the selective processes and the admixture episodes in play during the process of cat domestication, and unravel whether two independent domestication episodes occurred in the Near East and Egypt.
Claudio Ottoni is a post-doctoral fellow at the University of Rome "La Sapienza".
For Further Reading
A. Driscoll, et al. The Near Eastern origin of cat domestication. Science 317, 519–523 (2007).
B. Kaelin, et al. Specifying and sustaining pigmentation patterns in domestic and wild cats. Science 337, 1536–1541 (2012).
J. Montague, et al. Comparative analysis of the domestic cat genome reveals genetic signatures underlying feline biology and domestication. Proceedings of the National Academy of Sciences of the United States of America 111, 17230–17235 (2014).
VanNeer, et al. More evidence for cat taming at the Predynastic elite cemetery of Hierakonpolis (Upper Egypt). Journal of Archaeological Science 45, 103–111 (2014).
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