Felidae
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). (Clutton-Brock and Wilson, 2001; Denis, 1964; Grzimek, 2003; International Union for Conservation of Nature and Natural Resources, 2008; Kelsey-Wood, 1989; O'Brian, 2001; Vaughan, Ryan, and Czaplewski, 2000)

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. (Clutton-Brock and Wilson, 2001; Grzimek, 2003; Kelsey-Wood, 1989; O'Brian, 2001; Vaughan, Ryan, and Czaplewski, 2000)

The first cat-like mammals appeared around 60 million years ago (MYA) during the Eocene and culminated in the most specialized of the saber-tooths, Barbourofelis fricki. However, the phylogeny of saber-tooths and their ancestors (Nimravidae) is the subject of considerable debate and fossil evidence for these cat-like mammals does not exist after the Miocene. True felids first appeared during the early Oligocene and, although early ancestors of present day felids had short upper canines, felid radiations that occurred during the Miocene and Pliocene, such as Smilodon, appeared to specialize on large herbivores and had large, saber-like upper canines. Early felids were divided into two subfamilies, Machairodontinae (saber-toothed cats) and Felinae (conical-toothed cats). The many genera of saber-toothed cats are divided into three tribes (Metailurini, Homotheriini, and Smilodontini). Living and extinct conical-toothed cats are placed in one subfamily and one tribe, the Felini, but controversy surrounds generic-level classification of felids. Modern cats are closely related to hyenas, mongooses, and civets. These families, including the families Eupleridae and Nandiniidae, are in the suborder Feliformia. (Boorer, 1970; Clutton-Brock and Wilson, 2001; Colby, 1964; O'Brian, 2001; Turner, 1997; UCMP, 2010; Vaughan, Ryan, and Czaplewski, 2000)

Felids are native to every continent except Australia and Antarctica. Excluding domestic and feral cats (Felis catus), which are globally distributed, felids can be found everywhere except Australia, New Zealand, Japan, Madagascar, polar regions, and many isolated oceanic islands. (Denis, 1964; Feldhamer et al., 1999; Grzimek, 2003; Kelsey-Wood, 1989; Nowell and Jackson, 1996; Vaughan, Ryan, and Czaplewski, 2000)

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. (Grzimek, 2003; Nowell and Jackson, 1996)

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. (Boorer, 1970; Denis, 1964; Grzimek, 2003; Kelsey-Wood, 1989; Turner, 1997; Walker, 1975)

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. (Boorer, 1970; Feldhamer et al., 1999; Grzimek, 2003; Kitchener, 1991)

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. (Boorer, 1970; Denis, 1964; Grzimek, 2003; Kelsey-Wood, 1989; Walker, 1975)

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. (Grzimek, 2003; Ramel, 2008; Sunquist and Sunquist, 2002; Walker, 1975)

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 see 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. (Boorer, 1970; Kelsey-Wood, 1989; Turner, 1997)

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. (Boorer, 1970; Feldhamer et al., 1999; Grzimek, 2003; Leyhausen, 1979)

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. (Feldhamer et al., 1999; Grzimek, 2003; Turner, 1997; Vaughan, Ryan, and Czaplewski, 2000)

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. (Feldhamer et al., 1999; Turner, 1997; Vaughan, Ryan, and Czaplewski, 2000)

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. (Feldhamer et al., 1999; Kitchener, 1991; Packer, 2001; Turner, 1997)

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. (Feldhamer et al., 1999; Grzimek, 2003; Kelsey-Wood, 1989; Vaughan, Ryan, and Czaplewski, 2000)

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. (Feldhamer et al., 1999; Sunquist and Sunquist, 2002; Vaughan, Ryan, and Czaplewski, 2000)

Felids are apex predators that initiate top-down control and are often considered keystone species in their native habitats. Often preying upon the most vulnerable of individuals (e.g., young, old, or ill), felids promote robust prey populations that exhibit decreased vulnerability to disease and prevent overgrazing by large herbivores. For example, evidence suggests that white-tailed deer in Bear Island, Florida avoid forest habitat based on the presence or absence of Florida panthers. However, bobcats, which typically prey upon small mammals, opportunistically prey on deer in open habitat. Thus, in their attempt to avoid one felid predator, white-tailed deer have become increasingly vulnerable to another. (Kelsey-Wood, 1989; Maehr, Orlando, and Cox, 2005)

Domestic and wild felids are vulnerable to a large number of endoparasites including flatworms (Platyhelminthes), roundworms (Nematoda), thorny-headed worms (Acanthocephala), tongue worms (Pentastomida), and parasitic protozoa (Apicomplexa). Common felid ectoparasites consist of ticks and mites (Acari), sucking lice (Phthiraptera), fleas (Siphonaptera), mosquitoes (Culicidae), and flies (Diptera). (Millan et al., 2007; Patton and Rabinowitz, 1994; Patton et al., 1986)

Where feral domestic cats have been introduced, the diversity of small vertebrates (such as birds, lizards, and small mammals) has significantly declined. Felids attack and kill livestock, which can result in losses for farmers. Wild cats are capable of transmitting pathogens to domestic cats. Large cats occasionally kill and eat people, though a majority of attacks are often the result of accidental confrontations or involve sick or injured animals. In the Sunderbans of India, the largest contiguous parcel of halophytic forest in the world, tigers (Panthera tigris) kill several dozen people each year. (Grzimek, 2003; Kelsey-Wood, 1989)

Felids were first domesticated in Egypt between 4,000 and 7,000 years ago. Historically, cat pelts served as a symbol of status and power, a trend that continues to this day. In Africa, felids are often hunted for sport (i.e., trophies) and retaliatory killings by livestock farmers are not uncommon. In addition to their pelts, felids are desired for their claws and teeth. Traditional medicines may incorporate felid by-products, although their efficacy is unproven. Although international trade of wild felids and their by-products is illegal, domestic trade continues in some countries. In the ecotourism industry large cats have significant economic value in Africa and India and are sought out by tourists on both national and private reserves. Small cats primarily prey on rodents, hares, and rabbits, which helps control pest populations throughout much of their range. Large cats commonly prey on large herbivores, which reduces competition between livestock and native ungulates. (Grzimek, 2003; Kelsey-Wood, 1989; Vaughan, Ryan, and Czaplewski, 2000)

Major challenges to felid populations include habitat loss or fragmentation, management of cat-human interactions, the collection and killing of felids for the pet and fashion trades, and disappearance of natural prey. Additionally, reduced population sizes increase vulnerability to extinction due to natural disasters, epidemics, and inbreeding depression. According to the IUCN Redlist of Threatened Species, 29 of the 36 recognized species of felids are currently in decline, and 5 of the remaining 7 species have insufficient population data to determine demographic trends. Iberian lynx (Lynx pardinus) are listed as critically endangered and are one of the most endangered animals on the planet, with a maximum of 143 individuals remaining in 2 separate breeding populations. Including tigers (Panthera tigris) and snow leopards (Panthera uncia), 6 other species are listed as endangered. CITES, which was created in part over concerns that international fur trade would drive many felids to extinction, currently lists 23 species or subspecies under Appendix I, with all remaining species placed under Appendix II. The North American Endangered Species Act lists 8 species or subspecies of North American felids as threatened or endangered, including jaguars (Panthera onca), ocelots (Leopardus pardalis), and panthers (Puma concolor). (CITES, 2010; Grzimek, 2003; IUCN, 2010b; International Union for Conservation of Nature and Natural Resources, 2008; Nowell and Jackson, 1996; U. S. Fish and Wildlife Service, 2010)

Currently, conservation efforts are focused on habitat preservation, captive breeding, and reintroductions. Numerous cat species have been reintroduced or translocated throughout parts of their range where they were once extinct. Aside from the reintroduction of European wild cats in Bavaria, Canada lynx in northern New York State, and bobcats to Cumberland Island, Georgia, few reintroductions have been truly successful. The majority of felid reintroductions fail due to a lack of careful planning and execution, which is directly linked to a lack of time and money. In addition, a majority of large cat reintroductions fail because management teams don't take into consideration four important points. First, reintroduction efforts must consider the conditions under which past translocation events were successful, especially the movement of animals into established populations. Second, management teams often fail to appropriately train captive-bred animals to be successful predators in their native habitat. Third, prior to a reintroduction or translocation event it is imperative that the various genetic and morphological differences between different subpopulations are well understood. Finally, the support and receptivity of local human communities must be assessed prior to reintroducing a potentially dangerous predator. Many felid populations are currently in decline largely because of persecution by humans. If felid reintroduction is not supported by local communities, such attempts are likely to fail. (IUCN, 2010a; Nowell and Jackson, 1996)

In 1996, the IUCN published an action plan for the conservation of large cats, which included a list of 105 "priority projects". The "general conservation plan" called for a number actions that were believed to aid in the conservation of all felid species. For example, the establishment of a "cat conservation center" would result in a centralized data management center that would solicit potential donors for funding and help carry out the directives suggested by the conservation action plan as a whole. In addition to a generalized action plan, species specific action plans were formulated for 43 different cat species. Since 1996, the IUCN's Cat Specialist Group has helped launch numerous research efforts aimed at addressing the conservation goals outlined in their 1996 conservation plan. In 2004, the Cat Specialist Group established a "digital cat library" that contains more than 6,000 "papers and reports relevant to the conservation of wild cats", and in 2005 the first captive bred Iberian lynx litter was born, which served as a giant symbolic leap in the long journey of felid conservation. (IUCN, 2010a; Nowell and Jackson, 1996)