Humans and cats have had a most unusual relationship for the past 5000 years. While dogs may have initiated their relationship with humans as camp followers scavenging discarded foods and tagging along on hunting expeditions as hunter/gather bands wandered in search of food, it is likely that cats, being more territorial, waited until our ancestors put down roots and settled into a more sedentary agrarian lifestyle, around 9,000–10,000 years BP (Driscoll et al. 2007). Cats were probably barely noticed in the early stages of their relationship with humans. As the first farmers began to produce enough grain and crops to store excess for a later time, these stored foods attracted rodents and the wildcats that preyed upon them. These wildcats were shy and came to hunt within proximity of settlements when people were indoors or sleeping. Hunting at dusk and under the cover of darkness, they were able to feast upon an abundance of their preferred prey. Over time, humans may have noticed cats dashing back into hiding with a rodent prize in their grasp. These early agriculturalists were fighting a life-and-death contest with rodents to protect their hard-earned bounty. Seeing a cat with a dead rat may have given rise to the first iteration of the proverb, “The enemy of my enemy is my friend.” In the millennia since, cats have been viewed as allies, gods, satanic familiars, symbols of good fortune and bad luck, blood thirsty killers, and beloved companions. Beneath, and before all of this, there is a remarkable species that has adapted to living in a wide range of environments and situations. Their capacity to adapt to life in an apartment, a suburban home, a barn, or the edge of a forest stems from a rich behavioral repertoire that in some way is not all that different from that of their wild ancestors and relatives (Leyhausen 1979).

Archaeological and molecular evidence shows that the domestic cat Felis catus descended from the African wildcat Felis silvestris lybica somewhere in the region of the Fertile Crescent (Driscoll et al. 2007). The morphological similarity is evident as the wildcat looks very much like a large striped tabby cat. There are several other subspecies of Felis sylvestris, including populations that are found in Europe, southern Africa, and India. These subspecies are interfertile in regions where they overlap. However, of these subspecies, only F. silvestris lybica seems to posses the rudiments of a temperament that lends itself to taming, the first step in domestication. Experience with efforts to tame the even very young kittens of the other subspecies has not been fruitful (Serpell 2000). Young kittens of F. s. lybica can be tamed to tolerate close proximity with people. This is consistent with historical evidence that before domestication of the cat, people may have kept tamed wildcats to control rodents (Bradshaw 2013).

Domestication of the cat resulted in changes common in the domestication process for other species. The initial changes were likely related to behavior as cats became more tolerant to human proximity and other cats. Physical changes included a smaller body size and enhanced reproductive potential. Variations in color, coat patterns, hair length, body type, ears, and tails appeared later in the domestication process and were preserved by humans who bred the cats to retain and express these traits.

Archaeological evidence suggests that cats may have had a close relationship with humans by about 9500 years ago (Vigne et al. 2004). The bones of an 8-month-old cat were found buried near a human grave in Cyprus. It is likely that this was a wildcat that may have been tamed and kept by either the buried human or someone associated with them. It may be that some wildcats were caught and tamed similar to the fashion in which people have kept tamed raccoons and skunks. Remains of cats have also been found associated with humans 5500 years ago in an early agricultural village in China (Hu et al. 2014). Analysis of remains of humans, cats, and rats from this site showed substantial consumption of millet by all three groups. Combined with other evidence from the site, this suggests that rats consumed stored millet and that it is likely that the cats provided some assistance for these early farmers by killing rats.

It is clear that the domestic cat, as we currently know it, was a part of Egyptian culture 2600 BCE (Mellen 1940). During the Twenty-second Dynasty (945–715 BCE) with the ascension of the goddess Bastet in Egypt (Serpell 2000, p. 184), Bastet was represented as a cat and was associated with fertility and abundance. In one of the many ironies in our long relationship with cats, while cats were held in great esteem, they were also bred in great numbers in temples and then killed as sacrificial offerings (Armitage & Clutton-Brock 1981). The Egyptians attempted to restrict export of cats, but as the center of a vast trading empire it would have been nearly impossible to keep enterprising travelers from surreptitiously carrying a few cats with them as they moved to their next destination (Mellen 1940). They first spread across the Mediterranean region and by 500 BCE the image of a cat appears in Greece (Zeuner 1963). From Greece, cats moved on to Rome and thence throughout the Roman Empire. While never as popular with the Greeks or Romans as were dogs, cats did settle into a wide range of new places and environments.

The Middle Ages were a difficult time for cats in Europe (Lockwood 2005). They were associated with the practice of witchcraft (Serpell 2000), and they were frequently targeted in purges directed at suspected witches and heretics (Russell 1972). Cats did survive, and likely thrived during these difficult times. When European explorers began to travel the world in the 1400s, cats went with them. In this way, cats soon populated areas of the world they had not yet reached.

The Cat Fancy developed shortly after that of the Dog Fancy at the end of the 19th and beginning of the 20th centuries. Periodicals such as The Cat Journal and Cat Courier were available to offer products, advice, and information on various shows and events (Zawistowski 2008). Simpson (1903) published a comprehensive and influential book that included information on diets, breeding, and general care. She also noted that while dogs may be the friends of men, cats are more closely associated with women (p. vii), though this no longer seems to be the case (APPA 2013, p. 46). A significant event in our relationship with cats was the invention of cat litter in 1948 (Magitti 1996). Until this time, people who allowed cats into their homes used a variety of substrates, including sand, dirt, shredded paper, or ashes in boxes for their cats. None of these substrates provided the absorption and odor control benefits of the granulated clay, that is, kitty litter and having a “housecat” was a fragrant experience. In the decades since, a variety of other products have been introduced as alternatives to the original clay-based kitty litter, and human ingenuity has come up with a remarkable range of litter box designs, including automated versions. Regardless, managing the toilet habits of cats remains a critical part of a successful relationship. House soiling and litter box problems are among the most frequent complaints and concerns that people cite in dealing with pet cats (Purina 2000).

Nearly all domesticated species were derived from ancestral species that lived in social groups. Wolves lived in packs, birds lived in flocks, and the various livestock species lived in herds of various sizes and organization. Cats descended from a solitary carnivore (ferrets may be the only other domestic species descended from a solitary ancestor). Wildcats rarely spend time in association with conspecifics except when mating or caring for a litter. They tend to hold and defend territories (Driscoll et al. 2009). When rodents were attracted to human settlements, in turn attracting wildcats, the cats needed to adapt their solitary ways to exploit the surfeit of prey. The theory is that over time, those cats most comfortable staying in proximity to both humans and members of their own species benefited from the situation, reproduced, and passed their increasing tolerance for social living to their progeny. The result is a species that has a flexible social structure (Crowell-Davis et al. 2004). In areas where food is widely distributed, free-living cats may live a largely solitary existence. However, when food resources are adequate to support several or more cats, they will live in social group. This group will have an internal social structure as individual cats will recognize one another and engage in a variety of behaviors that support individual social relationships and overall group cohesion. Cats will form affiliative relationships, groom other cats, and sleep in close proximity. The basic structure of a “natural” cat group is matrilineal in nature, and the queen–litter relationship is the primary unit of organization. These cats will usually stay within a limited area that may be thought of as a territory. Multiple cats may have overlapping territories. Unlike many other species, it does not appear that cats “defend” their territorial boundaries (Feldman 1994). They will mark various locations in their territory by scratching trees, urinating, defecating, and rubbing on objects. These marking locations do not typically demark the boundaries of the cat’s territory and are more often found along preferred pathways through and within the territory. Fecal and urinary depositions were typically found in areas outside the core area of the territory. For the most part, the marking behavior seems to advertise the presence of the resident cat, rather than an explicit warning to stay away. It is more likely that resident cats will engage in aggressive behavior toward strange or new cats when they are initially entering the area. If the new cat is not driven off, it may eventually settle into the established social network. This is not all that dissimilar to what is observed when a new cat is introduced into a home with one or more resident cats. There will be initial periods of confrontation, but over time, the cats typically adjust and settle into an acceptable social relationship. Among free-roaming cats, males will typically have larger ranges that will overlap with multiple females and other male cats. The male cats will roam their ranges looking for food and females in estrus. An estrus female may attract multiple intact males and may mate with several different males when she is receptive. It can be difficult to compare the behavior of free-roaming cats with home-owned cats due to the fact that the majority of free-roaming cats are intact, around 98% (Wallace & Levy 2006), while home-owned cats are overwhelmingly neutered, around 80–85% (Trevejo et al. 2011; APPA 2013).

The nature and role of dominance hierarchies in cat social structure is unclear (Bradshaw & Lovett 2003). Their social structure is flexible based on the circumstances and a range of agonistic, defensive, and affiliative behaviors are employed to manage access to resources and contact with other cats. It does seem that cats in high-density situations may engage in greater levels of vigilance and affiliative/appeasement behaviors to mange living in close proximity to one another.

Reproductive behavior

The reproductive cycles of domestic female cats are keyed to seasonal light cycles. Increasing daylight in the spring stimulates physiological/hormonal changes that stimulate the female’s reproductive system. Domestic cats are reflexive ovulators. This means that while a female may be sexually receptive, she will not ovulate or release eggs for fertilization until she has mated. This is a reproductive strategy that makes good sense for what was once a solitary species and may not come across a possible mate soon after entering estrus. Females in estrus will solicit males, may mark more frequently, and engage in vocal displays to attract male cats. Domestic cats are polyandrous, meaning that a female may mate with multiple males during an estrus cycle. As a result, it is not unusual for a free-roaming female to produce a litter with multiple sires. Males will contest access to an estrus female and frequently engage in dramatic battles. The combined chorus of estrus females and aroused male cats is the source of frequent complaints by people living in an area with a population of free-roaming cats. Females will rub against the male cat and present her raised hindquarters to him in a position known as lordosis. The actual mating process is relatively short in duration, 30 s to several minutes, and cats do not “tie” in the manner that dogs will. The male cat has spines on his penis and these are thought to stimulate ovulation by the female. Once the male has ejaculated, he will disengage and move away. He will rarely “defend” the female and she may accept one or more additional mates in a brief period of time. If a female does not mate during estrous, she will cycle to a period of about 15 days when she is nonreceptive. She will continue to cycle through periods of receptive fertility and nonreceptive periods throughout the mating season. Females that cycle repeatedly and fail to mate and become pregnant are susceptible to pyometra, or an infection of the uterus.