Cats as predators and early domesticates in ancient human landscapes

Cats have had diverse relationships with humans, ranging from rodent control, to household pets, to cultural icons. The presence of rodents in grain stores in Neolithic farming settlements is widely thought to have led to the domestication of cats (1–3). Felid bones are rare in archaeological sites, however, and processes of cat domestication and dispersal are not well understood. A study by Krajcarz et al. (4) in PNAS reports on the initial spread of Near Eastern cats (Felis silvestris lybica/Felis catus), from southwest Asia into Europe ∼6,200 to 4,300 ya. Their unique data include Neolithic skeletal material from several Near Eastern cats found outside human settlements, and their analysis demonstrates that cats associated with early farmers in synanthropic or commensal relationships (5), hunting in agricultural landscapes. By documenting ancient ecological relationships in humanly modified landscapes, this isotopic research contributes to understanding landscape scale human niche construction (6, 7) and to future directions in domestication research (8–10).

The earliest cats discovered to date were buried in early agricultural settlements, and scholars have proposed commensal and mutualistic domestication pathways for their domestication (1–3). Direct archaeological evidence for a commensal relationship between millet farmers and small felids feeding within the human food web was documented at Quanhucan in China (Fig. 1) (∼5,560 to 5,280 ya) (11), where leopard cats (Prionailurus bengalensis) (12) hunted rodents in a farming village ecology and may have even been fed. However, this relationship did not lead to full domestication (12).

Fig. 1.

Early interactions between humans and cats. Location of sites with Near Eastern cats (F. s. lybica and F. catus) and leopard cats (P. bengalensis) feeding in early farming food webs (1, 5), early spread of Near Eastern cats outside their wild range (1, 2), cat burials (2, 3), and household cats in Egyptian cities (4). Key: 1, Southern Polish sites; 2, Cyprus, Shillourokambos; 3, Hierakonpolis; 4, Middle Kingdom Egypt, e.g., Thebes; 5, Quanhucan. Image credit: Lorraine Hu (Washington University in St. Louis, St. Louis, MO). Information on F. sylvestris distribution from ref. 1. Site locations from refs. 3, 4, 11, and 14.

Evidence for commensal relationships that resulted in domestication comes from agricultural villages and towns of the eastern Mediterranean and the Nile, in social settings in which animals that were never domesticated (e.g., fox, jungle cat, and baboon) also played prominent roles. Paradigm-shifting research in Cyprus revealed that mice colonized the island with early farmers by 10,000 ya, and a range of other wild and domestic animals were intentionally transported, including foxes and Near Eastern cats, ∼9,500 ya (8, 13) (Fig. 1). The burial of a cat (Felis sylvestris cf. lybica) with a person in a large farming village has suggested an early close relationship (3). In Egypt, the elite human cemetery at the Predynastic city of Hierakonpolis preserves evidence of subsidiary animal burials (wild and domestic) including five cats (Felis sylvestris) dating to ∼5,800 ya (14) (Fig. 1). Fine-grained research on birth seasonality and morphology suggests phenotypic change resulting from selection on cats in villages and towns along the Nile (14). It is not until 4,000 ya, when art and writing indicate that domestic cats played a role in family life and state religion in Egypt, that most scholars think cats were fully domestic (15). The hieroglyphs for “female cat” used as a girl’s nickname and wall paintings illustrate the role of cats in women’s lives and households (16, 17). However, none of these studies has explored the influence of humanly modified landscapes on ancient cat diets outside of villages and towns, or the extent to which cats were provisioned or independent. This is, in part, because of a focus on human intentionality in domestication and because of the lack of data on ancient cats.

Cats Living Outside Settlements

Krajcarz et al. (4) used an isotopic approach to examine diets and ecological and social relationships among people and the earliest Near Eastern cats during the spread of farming into Europe in the Neolithic (Fig. 1). Their findings bear on the question of whether the cats studied in southern Poland were house cats, feral cats, or whether they were wild Near Eastern cats that associated synanthropically with farmers and their fields and moved into the wild range of European wild cats as an invasive species. Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope signatures were collected for a broad range of Late Neolithic (ca. 4200 to 2300 BCE) taxa including cats, humans, dogs, birds, and rodents as well as comparative information from contemporary European wildcats and from domestic cats in Roman contexts. These data document food webs in which cats fed and allow sophisticated discrimination among potential cat prey taxa with varied isotopic signatures. The context of the cat specimens and the size of the sample of rodents and birds studied are unprecedented in cat domestication research. Since cats are rarely eaten and their bones seldom found in trash dumps even in villages, the chance of finding them in human landscapes distant from human settlements is extremely low. The six Late Neolithic Near Eastern cat skeletons they studied were recovered from nonanthropogenic contexts in four cave sites distant from human villages. These provide a unique window into human relationships with cats and selection processes in agricultural landscapes outside households and villages.

Krajcarz et al.’s (4) research reveals that the Late Neolithic Near Eastern cat diets differed considerably from those of people and dogs living in this ecosystem. They also differed from Later Roman cats. With isotopic signatures similar to those of people and dogs, the authors suggest that Roman cats were probably fed by their owners.

Krajcarz et al.’s research emphasizes the potential of integrated isotopic, morphological, and genetic approaches for examining the process of cat domestication.

Interestingly, the diets of the Late Neolithic Near Eastern cats studied also differed from those of Pre-Neolithic–Early Neolithic European wild cats that lived far from village communities. Krajcarz et al. (4) found that rodents that fed in agricultural landscapes (e.g., mice, voles, hazel grouse) characterized by high nitrogen values and interpreted as pests of farmed crops, made up a significant portion of the diets of Late Neolithic Near Eastern cats. These cats also ate some omnivorous migratory birds (e.g., thrushes and woodcocks), but wild forest animals made up only a small portion of their diets.

Krajcarz et al. (4) concluded that the cats that they studied fed mostly in agricultural fields but also ranged across diverse landscapes, including fields and woodlands, that varied from more to less intensely humanly modified and were part of a synanthropic food web. The authors also examine environmental change through time in the trophic niche of European wildcats. Their data indicate that indigenous and exotic cats shared an ecological niche but that European wild cats had a broader diet and preyed more on migratory birds than did Near Eastern cats.

The remaining question of whether the cats in southern Poland were wild camp followers (synanthropic and commensal) or a feral population with domestic counterparts in settlements might—as Krajcarz et al. (4) suggest—be addressed in the future by discoveries of cat remains in farming settlements. It is not at all clear, however, what biometric or genetic difference might be expected as early as 6,000 ya between wild living (feral) domestic cats (Felis catus) and synanthropic wild F. s. lybica hunting in an agricultural landscape far from its wild Asian range. Phenotypic change may be minimal, given the lack of evidence for strong directional selection in cat domestication.

From a binary perspective, whether the cats are considered wild or domestic matters. However, given our current understanding of the significance of relationships to domestication (18), the prevalence of gene flow (19), and the lag in subsequent morphological or genomic shifts generally (e.g., goats and donkeys) (10, 18–20), the question of classification is less interesting than understanding of the influence of selection in human environments on cat domestication and spread.

Cats in Ancient Human Landscapes

Krajcarz et al.’s (4) findings change the conversation regarding cat domestication by showing that Near Eastern cats, loosely associated with early farmers, were able to expand their range into Europe by moving with settlements, livestock, agriculture, and forest clearance. Instead of focusing on temporal shifts from Neolithic villages to later indoor or household cats like those living in Middle Kingdom Egypt, these isotopic data on cats in wider agricultural settings allow systematic consideration of the significance of outdoor cats to humans through time.

Extending this approach to cats in earlier human landscapes will be a priority for future research. Recent studies show that the ecological effects of long-term hunter-gatherer occupation attracted house mice to Natufian hunter-gatherer dwellings in the Levant by 15,000 ya (8, 9), revealing that rodent food sources for cats in human settlements preceded grain storage. These mouse populations varied with climate and human mobility (9), drawing attention to fluctuating opportunities for cats in human settlements through time and the possibility of nondirectional selection.

So far, cats have not been found in forager settlements or landscapes, but the appearance of Near Eastern cats with early farming communities in Cyprus by 10,000 ya supports a long time frame for interactions with domestic, feral, or wild cats in farming settlements in the eastern Mediterranean (3, 8). Krajcarz et al.’s (4) findings also raise the possibility that the appearance of cats on Cyprus could also be an early example of range expansion of synanthropic wild cats adapted to agricultural landscapes, which followed coastal routes.

Future research will undoubtedly reveal a complex set of interactions among humans and cats across space and through time. Understanding of ancient community ecology in human settings is needed at multiple scales, from landscapes to households in a range of geographic and temporal contexts. Krajcarz et al.’s (4) research emphasizes the potential of integrated isotopic, morphological, and genetic approaches for examining the process of cat domestication.