IACUC Learning Module - Cats | Previous Next |
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Over a million distinct kinds of animals live on the Earth today, but none excite more respect and admiration than the members of the cat family. For Felis catus domestication began in the Middle East. The cat is a newcomer, as time goes, to the company of man, and she is unique as the one and only animal that man took to himself for a non-utilitarian purpose. That she is the supreme enemy of small vermin is really an extra boon, a bonus that man earned by the way. She may well have taken to man because rats and mice were to be found wherever he dwelt-but that is a different story. Her independent nature and capacity for keeping her own counsel make her a very different pet from the slavishly adoring dog, and one can be sure that the cat’s acceptance of man is certainly on her own terms. They were worshiped in Egypt and treasured in the Far East. The cat suffered undue persecution in Europe during the early Christian era because of their association with the old pagan religions. However, the role of cats in destroying the rats that carried the Black Death across Europe regained them some status. Comprising only about 40 out of the million species, they represent the most supremely efficient muscular machines. |
Cats belong to the animal group known as mammals. Evolved from reptiles 200 million years ago. The first mammals were small creatures and once the dinosaurs met their doom then they became the dominant animals. The most accomplished hunters are the carnivores. Among these are cat-like animals such as civets, genets, mongooses, hyenas, and the true big cats such as the lion, tiger, leopard, jaguar, the cheetah, and small cats such as the lynx, ocelot and margay. A distinctive feature of the carnivores is a set of teeth adapted to cutting and tearing meat. Members of the cat family developed from the miacids.
All cats are recognizably related. Domestic breeds of cat show very little variation in appearance, all being of relatively similar size. The rounded head and agile, light footed body immediately identify a cat, whatever its size or markings, and suggest that all cats evolved from a common prehistoric ancestor. Precise features, such as the head shape and coat length, may well differ, however, particularly in the case of pedigree cats that have been modified by selective breeding over generations in order to conform to the standards laid down by breeders and cat associations. In many ways, though, domestic cats are still very similar to their wild ancestors and possess the same athleticism and hunting skills. These features are vividly demonstrated by feral cats-cats that have reverted back to nature, living wild wherever they find suitable cover. There are also certain internal anatomical characteristics that almost all cats have in common, one of which is having 38 chromosomes.
Cats make up the family Felidae within the order carnivora of the class Mammalia. Zoologists disagree on exact number of species though most say 38 including the domestic cat.
The domestic cat retains many of the behavioral traits associated with its wild relatives. Adaptations to domestic living have occurred, most noticeably in territorial matters. Cats in urban areas inevitably have to share space, rather than maintain large territories, but as they are fed by their owners, and do not have to fend for themselves, this does not cause great problems.
Cats are born with a natural hunting instinct, but they have
to learn the specific skills required. They observe their mother and other cats
from early kittenhood. Practice is repeatedly needed in order to become
perfected hunters. Catching and climbing are two more skills that kittens have
to learn by trial and error. Cats are extremely agile climbers, using both legs
and claws to anchor themselves firmly on a branch. Kittens learn these maneuvers
by trial and error. Balance is maintained by the semi-circular canals in the
ears. If a cat begins to fall, its body will swing around so it lands on its
feet. Grooming is done everyday. The rough surface of their tongues helps
remove loose fur, but if swallowed may cause a fur ball or mat in the stomach.
These are usually vomited up and considered normal. Male cats who have not
been neutered tend to spray their pungent urine both inside and outside the home
as a means of staking out their territory. Scratching and rubbing against
objects, as well as against people, also serves to mark out territory by scent.
As night hunters, cats rely on a special layer of cells (tapetum lucidum) in the
retina, at the back of their eyes, which reflects light back, increasing its
intensity. This causes the cat’s eyes to appear to glow in the dark.
Cats are highly social animals. Feral and wild cats live in groups based on the mother-kitten unit, some mature males assume a paternal roll while others become solitary nomads. Cats living with people are usually more tolerant of each other in multi-cat households especially if they are introduced as kittens. A lone pet will generally direct its social urges towards its owner.
Within any cat group, individual members greet each other affectionately with nose kisses, body-rubbing and sniffing at anal regions. They may sleep in companionable heaps, groom each other, play and defend their home range together. Outside the immediate family circle, the urge for group socialization persists. Neighboring cats that are allowed outdoors by their owners soon become members of a kind of feline social club that meet on neutral ground at night. Wild and semi-wild cats develop a complex social organization with a distinct hierarchy from submissive up to dominant animals. This varies according to the time, place and context of meetings.
The female hierarchy, which is very loose-knit, is based on motherhood with each litter a female goes up the social scale a little. But at the time when she actually has the kittens, whichever litter it is, her dominant status increases dramatically. Females neutered after they have borne litters drop down the hierarchy very quickly; if they are neutered before they ever come into heat, they never even establish themselves.
The tomcat hierarchy is rather different. It is devoted to
the ranking of every tom in the neighborhood according to his machismo quotient.
Dominant males command the largest territory but do not necessarily mate with
the greatest number of females. No un-neutered tom escapes initiation. Whether a
newcomer to the district or an adolescent reaching maturity, he is visited by
established males. He must usually fight several other males before his rank is
established. These fights may take place over several nights, but once
established a tom should not need to fight again unless he is challenging for a
higher rank, is himself challenged or takes part in fighting a newcomer.
Toms will fight for a chance to mate, assembling outside the female’s home or wherever she may be to challenge each other. One puzzling aspect is the fact that the female is not obliged to mate with the winner and may choose losers unopposed by superior toms. It may therefore be that the fighting is stimulated by a territorial rather than a sexual urge, as the toms are necessarily trespassing on alien ground. Proximity to one another may provoke fighting.
The hierarchy of the brotherhood is very rigid. The leader may be toppled occasionally by the next in line, or an incoming tom may prove stronger than all the ranks. Toms that are socially graded when intact and are then neutered gradually slip down the hierarchy, their descent paralleling the drop in male sex hormone levels. Cats neutered before initiation have no place in the hierarchy.
When large numbers of cats are forcibly housed together in a small space, a very rigid status or dominance order develops as a means of avoiding social breakdown. A single ruler usually emerges, a dominant cat that has absolute priority over all the others for sleeping areas, food etc. At the other end of the scale there are usually two cats which are the scapegoats of the community and are uniformly abused by the rest of the colony, all of whom share equal middle rank.
The social life most cats enjoy is supported and reinforced by their ability to communicate with each other through smell, body language and vocalizations. They usually recognize each other by body smell. Cats who are acquaintances always greet each other by touching noses and then sniffing at the head and anal areas. Glandular secretions in these areas identify individual cats because each has its own unique scent. Some cats will rub each other’s bodies, scent marking, for future reference. Pet cats rub their owners for the same reason. Scent-marking objects and territorial boundaries by scratching, spraying and rubbing is communication at a distance. Apart from helping to define the limits of a cat’s territory, it leaves a record for other cats to estimate how recently the owner passed by.
Cat’s body language is composed of many elements-posture, tail position, angle of head, facial expression, etc. There are a range of facial expressions that register a cat’s mood and reactions from outrage to ecstasy. Making faces is a fundamental mode of feline communication.
A happy cat (1) has perky ears, pupils normal for the prevailing light level and relaxed whiskers.
An angry cat (2) keeps its ears erect and furled back; its pupils constrict to slits and its whiskers "bristle" forwards.
A frightened cat (3) is "wide-eyed" and lays its ears and whiskers flat.
A cat playing or hunting (4) wears a face between those of anger and fear; the pupils are open but the ears are pricked, and like the whiskers, thrust forward.
The pleasure of being petted shows in the half closed eyes of the face of ecstasy (5).
Tails can be just as expressive. Adult cats raise their tails as a greeting gesture towards friendly humans and other cats. A bristling vertical tail is slightly threatening. A flailing tail is an offensive threat and an arched bristling tail a defensive threat. The posture of the body itself may range from the crouching submissive pose to the well-known arched back signifying a defensive threat.
The cat is more than just a mammal, it is a highly successful member of the group known as carnivores, and from the standard mammalian basis has evolved a variety of adaptations to suit a hunting, meat-eating way of life. Modifications to the skeletal and muscular systems give it a strong, flexible, fast-moving hunter’s body. The jaw is short and has only 30 teeth-(fewer than any other carnivore)-but they are all built to cut meat, and give the cat a lethal bite.
Cats designed as hunters are strong, quick and agile. They have a well muscled body that gives strength with a skeleton that gives exceptional flexibility and a highly developed cerebellum which is devoted to the co-ordination of sense organs and muscles, producing the controlled movements essential to a predator. A unique feline asset is their retractable claws.
Any cat watcher will realize the importance of smell for individual recognition from the way in which any new object, person or cat is thoroughly sniffed before being tolerated. Also, food is first identified by the sense of smell and only if acceptable will it be tasted and eaten. Smell and taste stimuli also dominate the sexual and aggressive displays of cats.
Of the 1,267,828 non-rodent animals used in research in the United States in 1997, only 26,091, or 2% of these were cats. Furthermore, use of cats in research in this country has declined dramatically during the past two decades from a high of 74,000 in 1974, amounting to 65% reduction (Animal Care division of APHIS, USDA). If the importance of cats as a research specimen was judged entirely on these numbers, one might conclude incorrectly that cats do not contribute significantly to biomedical research. In fact, cats contribute significantly to science, and their special biological characteristics and diseases rank them as the favored species for several disciplines, including experimental neurology, some aspects of ophthalmology, retrovirus research, inherited diseases and immunodeficiency diseases.
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