Cats

With the exception of Antarctica, Australia, New Zealand, Madagascar, Japan, and most oceanic islands, native populations of cats are found worldwide, and one species, domestic cats, have been introduced nearly everywhere humans currently exist. Although some authorities recognize only a few genera, most accounts of Felidae recognize 18 genera and 36 species. With the exception of the largest cats, most are adept climbers, and many are skilled swimmers. Most felids are solitary. Often, felids are separated into two distinct subgroups, large cats and small cats. Generally, small cats are those that, due to a hardening of the hyoid bone, have an inability to roar. Felidae consists of 2 subfamilies, Pantherinae (e.g., lions and tigers) and Felinae (e.g., bobcats, pumas, and cheetahs).

Felids are perhaps the most morphologically specialized hunters of all carnivores, often taking prey as large as themselves and occasionally taking prey several times their own size. Unlike other carnivores, felids rely almost exclusively on prey that they have killed themselves. They are agile hunters, hunting mostly at night, with diets consisting of fresh meat or carrion. Felids are found in all terrestrial habitats except treeless tundra and polar ice caps.

Habitat

Cats are found in all terrestrial habitats except treeless tundra and polar ice regions. Most species are habitat generalists and can be found in a wide range of environments. However, few have adapted to a limited range of habitats. For example, optimal habitat for sand cats (Felis margarita) consists of sandy and stony deserts. Domestic and feral cats (F. catus) are ubiquitous globally and are especially pervasive in urban and suburban areas.

Physical Description

All felids bear a strong resemblance to one another. Unlike members of the family Canidae, felids have a short rostrum and tooth row, which increases bite force. Loss or reduction of cheek teeth is particularly apparent in felids, which have a typical dental formula of 3/3, 1/1, 3/2, 1/1 = 30. In most species, the upper premolar is significantly reduced and in Lynx, has been completely lost. Felids have well developed carnassials. Their cheek teeth are secodont and are specialized for shearing. Felid canines tend to be long and conical and are ideal for puncturing prey tissues with minimal force. Besides having a short rostrum, felids also have large bullae that are divided by a septum; no alisphenoid canal, and paroccipital processes flattened against the bullae. Felids also have a vestigial or absent baculum and retractable claws. Distal segments of digits in the relaxed position are pulled back and up into a sheath by an elastic segment, which prevents claws from becoming blunt. Cheetahs are the exception as they cannot retract their claws and, when attacking prey, they tend to run into them so that they fall, much like canids. Cats have five toes on their forefeet and four on their hindfeet. They are digitigrade, and their metapodials are moderately long but never fused.

Felids range in body mass from 2 kg in black-footed cats (Felis negripes) to 300 kg in tigers (Panthera tigris), and exhibit sexual dimorphism, with males being larger and more muscular than females. In some species, such as lions (Panthera leo), males may also have ornamentation that is used to attract potential mates. Throughout their range, felid coats are longest where temperatures tend to be coldest (e.g., snow leopards). Felids exhibit a wide range of colors, from black to orange to white, and many species have cryptically colored coats containing rosettes, spots, and stripes that help camouflage them while hunting for prey. While melanistic variants (solid black) are common in many species, completely white individuals tend to be rare. A great deal of color variation can occur within individual species and newborns tend to have different coloration than adults. For example, adult cougars (Puma concolor) rarely have spots while kittens almost always have spots. In general, the ventral surface of felids tends to be pale while the face, tail, and back of the ears often have black or white markings.

Felids have a number of morphological adaptations that have allowed them to become the most adept hunters in the order Carnivora. They have digitigrade posture that results in a rapid stride rate and powerful forelimbs that help them capture and retain large prey. Often, felids are cryptically colored, which helps camouflage them while hunting. In addition, most felids have large eyes and exceptional vision. In nocturnal species, the tapetum lucidum helps intensify limited light. Many species also have large semi-rotating ears. Finally, the felid tongue has a sandpaper-like texture due to posteriorly directed papillae on its dorsal surface, which are thought to help retain food in the mouth and remove tissue from the bones of prey.

Reproduction

Felids are most often classified as polygynous but can exhibit polygynandrous behavior as well. Estrous lasts from 1 to 21 days and females may have multiple estrous cycles until they become pregnant. Females advertise estrus to potential mates through vocalizations, scent marking, and restlessness. As with most polygynous species, males compete for access to mates via displays and fighting, and successful males court mates through vocalizations and direct physical contact (e.g., rubbing on the female). During courtship, successful males may also approach receptive females with their head lowered. While the act of copulation lasts less than a minute, multiple copulations can occur over a period of several days, which may help induce ovulation. After several days, males may leave in order to find additional estrous females, in which case another male takes his place.

In felids, male territories often encompass those of multiple females (for an exception Panther leo) and males mate with females that reside within his territory. Most conspecific interactions occur during mating season or as a result of territorial disputes among rival males. Indirect interactions via scent markings or vocalizations help reduce the number of fatal interactions.

The act of copulation is aggressive and brief and may be repeated multiple times an hour for several days. Repeated copulation is thought to induce ovulation in females. Most species are polygynous and polyestrous, with estrous cycles lasting from from 1 to 3 days. Most felids are non-seasonal breeders, but in areas of extreme climatic or prey variability, parturition occurs during the most favorable times of the year. Small-bodied cats tend to have 3 litters per year, while large cats average 1 litter every 18 months. The interval between birthing events may depend on maturation rates of young, body size, food availability, or recent loss of litter. For example, if a female loses her litter, she can come into estrus within a few weeks. Although most litters contain 2 to 4 cubs, females can give birth to as many as 8 cubs in a litter. Gestation lasts from 2 months in small cats to 3 months in lions and tigers.

Felid cubs are born altricial, as newborns are often blind and deaf, rendering them defenseless. Mothers often hide newborns in dens, rock crevices, or tree hollows until they are mobile. Cubs remain with their mother until they can hunt on their own. Weaning begins at the introduction of solid food and ranges in length from 28 days (domestic cats) to 100 days (lions and tigers). Felids reach sexual maturity in less than a year for small cats and up to 2 years for large cats. Typically, cats do not produce their first litter until they have established a home range, which usually does not occur until they are 3 or 4 years of age. Although age of independence is highly variable, many species become independent around 18 months of age. Unlike most felids, lions are very social and females take turns nursing young born to other pride members (i.e., communal nursing) while absent mothers are hunting for food.

With the exception of lions, females are the sole caretakers of young felids. Mothers hide their cubs in dens, rock crevices, or tree hollows while they are away hunting and young hide until she returns. Weaning begins at the introduction of solid food, around 28 days in domestic cats (Felis catus) and 100 days in lions. Females teach cubs how to stalk, pounce, and kill. Weaning is complete when cubs can eat meat and help hunt for prey. Juvenile felids spend a majority of their time “role playing,” which helps develop important hunting skills. Juveniles are independent once they become competent hunters, though they may remain in their mother’s territory for up to a year before they establish their own. Most felids do not begin reproducing until they have their own territories. Although male lions use infanticide to eliminate unrelated young during pride takeover events, they also provide a significant degree of parental care to their own offspring, protecting cubs while they feed and allowing mothers to rest.

Lifespan/Longevity

Although many cats do not live beyond their first birthday, felid lifespan ranges from 15 to 30 years old. In the wild, juvenile deaths are normally due to predation. In captivity, however, juvenile deaths are often due to stillbirths, cannibalism, maternal neglect, hypothermia, and congenital disorder.

Behavior

With the exception of lions (Panthera leo), which form prides, felids are solitary animals that only come together to mate. They tend to hunt at night (for an exception Acinonyx jubatus) and, although most are primarily nocturnal, activity levels peak during dusk and dawn. Most cats are exceptional climbers and some species are skilled swimmers. When conspecifics meet, their tail posture, position of the ears, and exposure of teeth reveals their level of tolerance. Scent marking, rubbing, and scratching trees are used to mark territorial boundaries and communicate dominance and fertility.

Most felids stalk, crouch, wait, and pounce while hunting prey. They avoid long chases typical of canids and are considered ambush predators. Small prey are killed with a specialized bite to the base of the skull, which severs the spinal cord. Large prey are typically killed by suffocation. Prior to eating, some species drag carcass by the nape to a secluded location. Most small cats feed by crouching over their prey without using their paws, whereas large cats eat while lying down. Felids are instinctive hunters and, if given the opportunity, they will kill more prey than they can eat.

Communication and Perception

Felids have acute senses of smell, hearing, and sight. In addition to the tapetum lucidum, a layer of reflective tissue in the eye of many vertebrates, felids have a modified pupil that allows for excellent vision in a wide range of environments. The felid pupil consists of a vertical slit that expands in low light conditions and contracts in high light conditions. Felids have relatively large pinnae that can rotate to allow for multidirectional hearing without rotating their head. Well-developed vibrissae, which are located above the eyes, on the muzzle, and on the ventral surface of forepaws between the digits, play an important role in tactile sensory reception. Similar to other carnivores, felids have haptic receptors inside their digits that allows them to sense temperature, pressure, and other stimuli.

Felids are solitary animals that scent mark territories with facial glands and urine. They also mark territorial boundaries by clawing tree trunks. Like many vertebrates, felids have a vomeronasal organ, or Jacobson’s organ, that allows them to detect pheromones. This olfactory sense organ is found at the base of the nasal cavity and plays an important role in conspecific interactions, especially those related to reproduction. For example, after smelling the genital area or urine of a potential mate, males curl their upper lip toward their nostrils (i.e., the Flehmen response). Using the vomeronasal organ, this allows males to assess the mating condition and quality of potential mates. It is thought that input from the vomeronasal organ and the olfactory bulbs significantly contribute to mating activity.

Due to their nocturnal and solitary lifestyles, investigating audible communication in felids has proven difficult. However, the calls of many carnivores are known to signal individual recognition and territorial boundaries. It is thought that by observing domestic cats (Felis catus), one can hear a majority of the sounds made by most felids. They purr, meow, growl, hiss, spit, and scream. The hyoid apparatus of small-bodied cats is hardened, resulting in an inability to roar. Large-bodied cats have the capability to roar, which is thought to serve as a form of long-distance communication. For example, lions typically roar at night to advertise territories. Research suggests that lionesses can identify the sex of a roaring individual and lionesses respond differently to different numbers of roaring individuals.

Food Habits

Morphologically, felids are considered the most specialized of all carnivores in the order Carnivora. They are at top of the food web in most ecosystems, as their diet consists almost entirely of animals. Occasionally, felids ingest grass to help pass fur balls, a by-product of constant grooming. Some genera ingest fruit to help offset water requirements. Felids may eat the viscera (i.e., internal organs) of prey, thus consuming partially digested plant biomass. Although they typically hunt for large prey (e.g., Perissodactyla and Artiodactyla), when the opportunity arises large cats may eat carrion as well. Small cats predominantly prey upon rodents and rabbits or hares. When available, small cats also feed upon reptiles, amphibians, birds, fish, crustaceans, and arthropods. Some species cache food and may drag prey carcasses into nearby trees prior to feeding (e.g., Panthera pardus). Fishing cats and flat-headed cats are unique among felids, as they are especially adapted for preying upon fish and frogs.

Predation

Felids are typically apex predators (i.e., predators with no predators of their own), but young are vulnerable to predation until they are capable of defending themselves. Many species are cryptically colored, which allows them to remain camouflaged while in their native habitat. Although not an act of predation, many large cats are intolerant of heterospecific felids. For example, lions readily kill leopards, which are known to kill cheetahs. During attempted pride takeovers, male lions commit infanticide as a way of inducing estrus in pride females and eliminating the offspring of rival males. About one quarter of lion cub deaths can be attributed to infanticide, which also occurs in pumas.