Procyonidae is a New World family of the order Carnivora. It includes the raccoons, ringtails, cacomistles, coatis, kinkajous, olingos, and olinguitos. Procyonids inhabit a wide range of environments and are generally omnivorous.

Procyonids are generally small to medium-sized animals, ranging from slightly less than 1 kg to over 20 kg in weight. Some species have slender bodies, while others are stocky. All have medium or long tails. The pelage is gray or brown, sometimes with contrasting markings on the face and light and dark rings around the tail. Most species have relatively short, broad faces; and short but erect ears, which may be rounded or pointed. Forefeet and hindfeet have 5 digits, and procyonids are plantigrade, often walking with a bear-like shuffle. The claws are short and curved. In some species they can be partially retracted. The tail of of species, the kinkajou, is prehensile, and that of coatis is very mobile and is used for balancing during climbing. Males have a well-developed, bilobed baculum.

Procyonid skulls have relatively short rostrums (shorter than canids, longer than felids). They lack alisphenoid canals, but they have well-developed paroccipital processes. Their incisors are unspecialized, and their canines are moderately long and ovate (not round) in cross section. The molars are wide and at least somewhat bunodont. Most species lack secodont carnassials. The dental formula is 3/3, 1/1, 3-4/3-4, 2/2-3 = 36-42.

Most members of Procyonidae are solitary; however, some species form groups. Coati females will form bands of 4 to 24 individuals that forage together, while kinkajous have been found to form social groups of two males and one female. Certain procyonids give birth to one offspring like ringtails, olingos, and kinkajous while raccoons and coatis give birth to litters that range in size from 2 to 6 offspring.

Procyonids are omnivorous. They consume both plant and animal material, including small mammals and birds. Raccoons use their front paws to feel for food items in murky water or leaf litter. Ringtails inspect likely niches and hiding spots in their rocky habitats, hunting for rodents, birds, centipedes, and anything else edible. They are excellent mousers, pouncing and killing with a bite to the back of the rodent’s neck. Coatis dig in the soil and leaf litter using their long claws or their noses to turn up grubs, worms, or other invertebrates. They also turn over large rocks with their front paws to search for invertebrates, lizards, and snakes.

All species are to some degree arboreal, often seeking refuge in the trees when pursued by predators. Most are nocturnal, often denning in hollow trees during the day.

Raccoons are nocturnal and usually solitary, unless they congregate at man-made food sources such as picnic areas or campgrounds. They prefer brushy, thickly vegetated habitats, but adapt very well to the many artificial ponds, lakes, and wetlands found in the suburbs and housing developments. They can eat almost anything; their dexterous paws can easily open garbage cans, so they can readily take advantage of discarded food. In the warm desert climate, a raccoon may sleep away the day out in the open, draped over a tree branch.

Ringtails are strictly nocturnal animals, using their large eyes and keen sense of smell to locate prey. They are excellent climbers and leapers, using their long tails for balance as they negotiate steep canyon walls or trees with equal ease. The ringtails have semi-retractable claws and can rotate their hind feet 180 degrees, allowing them to descend cliffs face first. They den in niches in rock walls, boulder piles, or hollow trees. Ringtails are solitary, only pairing up for a few days of mating in April. The 2 to 4 kits are born in June. By fall the young can hunt for themselves and soon disperse. Though fierce little fighters, ringtails fall prey to great horned owls, bobcats, and coyotes. When frightened, they emit a musky odor from anal scent glands.

Coatis are diurnal, active mostly in the morning and late afternoon, then spending the night in trees or caves. As coatis forage through an area they travel with their long tails held vertically.

The Mustelidae are a diverse family of carnivoran mammals, including weasels, badgers, otters, polecats, martens, grisons, and wolverines. Otherwise known as mustelids, they form the largest family in the suborder Caniformia of the order Carnivora with about 66 to 70 species in nine subfamilies.

Mustelids inhabit all continents except Australia and Antarctica, and do not occur on Madagascar or oceanic islands. Members of this group can be found in diverse habitats, which include both terrestrial, aquatic and marine environments. Mustelids are mainly carnivorous, with various members of the family exploiting a great diversity of both vertebrate and invertebrate prey. Mustelids are generally proficient hunters; some weasels can take prey larger than themselves. Members of this family often hunt in burrows and crevices, and some species have evolved to become adept at climbing trees (e.g., marten) or swimming (e.g., sea otters, mink) in search of prey.

Generally, mustelids have elongate bodies with short legs and a short rostrum, as typified by weasels, ferrets, mink, and otters. Wolverines and badgers have broader bodies. An order of magnitude difference in size exists between the smallest and largest mustelid species. The smallest species is the least weasel (Mustela nivalis), weighing between 35 and 250 g. Wolverines (Gulo gulo) and sea otters (Enhydra lutris) reach 32 kg and 45 kg, respectively. All mustelids have well developed anal scent glands, which serve various functions, including territorial marking and defense.

Habitat

Mustelidae are distributed from the arctic to the tropics and occupy nearly all terrestrial habitats. Several species are semi- or nearly fully aquatic and inhabit freshwater rivers and streams, as well as coastal marine waters.

Physical Description

Adult mustelids range in size from 114 mm and 25 g (least weasel) to over 1 m and 45 kg (sea otters). These animals are generally long-bodied with short legs. Most species have slender bodies, but some, like badgers and wolverines have much broader bodies. The skull is elongate with a relatively short rostrum. Adult males are generally about 25% larger than females of the same species. The ears are short, as are the legs, each of which bears five digits. The claws do not retract and, in digging species, are especially robust. Mustelids are digitigrade or plantigrade. The dental formula varies among species: 3/3, 1/1, 2-4/2-4, 1/1-2 = 28-38. The canines are long, and the carnassials are well-developed. The upper molars are often narrow in the middle, giving them an hourglass shape. Mustelids have a powerful bite; in many species, the large postglenoid process locks the lower jaw into the upper, causing the lower jaw to only move in the vertical plane, without any rotary motion.

Reproduction

Mating systems vary both within and among species. Many species are polygynous and/or promiscuous. Some species are social, while others are solitary. Social organization can vary within species as well. Mustelids require prolonged periods of copulation to induce ovulation of an unfertilzed egg. As a result, copulation may last for several hours before fertilization can be successful.

Most mustelids breed seasonally, but the length of the reproductive period varies among species. Day length often dictates the onset of the breeding season, which usually lasts 3 to 4 months. Many mustelids undergo delayed implantation, with the fertilized embryo taking up to 10 months (e.g. Meles meles) to implant in the uterus in some species. Environmental conditions such as temperature and day length determine when implantation occurs. Mustelids that live in more seasonal climates are more likely to exhibit delayed implantation. Following implantation, gestation typically lasts 30 to 65 days. Females give birth to a single litter each season, the size of which varies within and among species. For example, sables have an average litter size of 2.2, but can give birth to anywhere from 1 to 7 pups. The mountain weasel averages 8.7 pups per litter, but can have between 3 and 14 young in a single bout of reproduction. Generally, mustelids are altricial, being born small and blind. They reach sexual maturity between 8 months and two years following birth.

Young are generally born in an alricial state, requiring extenisive care and protection from their mother. Young mustelids typically are able to care for themselves when they are about two months old. Females defend territories in order to acquire enough resources to care for their young and most often nurse and protect them in a burrow or den.

Lifespan

Mustelids typically live between 5 and 20 years in the wild.

Behavior

Members of the family Mustelidae are either diurnal or nocturnal. Many of the long, narrow-bodied species are quick and agile, and move in a bounding, scampering fashion. The broader-bodied forms have a more lumbering gait. Some species are adept climbers, while others are excellent swimmers. Many species spend a great deal of time on the ground, searching for food in crevices, burrows, or under cover. Many species shelter in burrows.

Social behavior varies both within and among species, and may vary in relation to local environmental conditions such as food availability. For example, European badgers are known to form groups with several males and females that are all reproductively active within the group. Yet in other parts of their range, European badgers may live solitarily or in pairs.Many species are territorial for at least part of the year, with individuals competing over hunting areas or access to mates (e.g., Mustela erminea).

Communication and Perception

Vision and hearing are important in Mustelidae, but olfaction is particularly well developed. In addition to using scent cues to find food, scent-marking is the main form of communication in this family. Secretions from well-developed scent glands function in territorial interactions, indicate reproductive state, and are used in other social contexts. The degree and function of scent marking varies among species, and according to social and environmental conditions within species.

Food Habits

Mustelids are primarily carnivorous, but some species may at times eat plant material. A wide range of animal taxa are preyed upon by various members of this family; many mustelids are opportunistic feeders rather than specialists. However, many mustelids are especially adept at capturing small, mammalian prey. Weasels, for example, are capable of chasing and capturing rodents in their burrows. Otters are well-adapted to chasing and capturing aquatic prey, including fish, crustaceans, and other aquatic invertebrates. Mustelids hunt in a variety of terrestrial, aquatic, and arboreal habitats. Some species regularly prey on animals larger than themselves. Some species have been known to store food (e.g., Mustela, Gulo).

Predation

Mustelids are generally small carnivores, and are therefore subject to predation by larger carnivores such as canids with which they co-occur. They may also fall prey to large snakes (Serpentes), raptors (Falconiformes), and owls (Strigiformes). Some mustelids secrete noxious chemicals to discourage predators. In some of these species, aposematic color patterns can help ward off predators.

The family Mephitidae, which includes the skunks and stink badgers, is comprised of four extant genera (Mephitis, Conepatus, Spilogale and Mydaus) and 13 species. Three of the four genera of skunks inhabit the New World, collectively ranging from Canada to central South America; the exception are stink badgers (Mydaus), which occur on islands in Indonesia and the Philippines.

Habitat

Members of the family Mephitidae can be found in a variety of habitats, including relatively open forests, grasslands, agricultural areas, meadows, open fields, and rocky montane areas. Stink badgers may even spend some of their time in caves. Mephitids generally do not occur in very dense forests or in wetlands. During the day, skunks and stink badgers seek shelter in burrows or under the cover of rocks or logs. They can dig the burrows themselves, or may use the dens of other species, such as marmots or badgers. At night, skunks and stink badgers come out from their dens and forage. Some skunks are agile climbers (e.g., Spilogale) and can be found in trees in search of food or to avoid predators.

Physical Description

Skunks and stink badgers can be recognized by their striking color patters. They are generally black (or sometimes brown) with a prominent, contrasting pattern of white fur on their faces, backs, and/or their tails. Generally, they have either white spots, or a white stripe running from their head, down their back to their tail. Patterns vary within and among species. For example, spotted skunks, as the name implies, have many white spots on a black background. Striped skunks have white dorsal stripes of varying thickness and length that may or may not run through the tail or extend onto the head. Coloration in skunks and stink badgers serves as an aposematic signal to would-be predators. All mephitids have extremely well-developed anal scent glands with which they produce noxious odors to deter threats. The product of the scent glands is secreted through nipples near the anus, and can be projected between 1 and 6 meters towards a threatening animal.

Mephitids have a relatively long rostrum (although it is not so large in Spilogale), broad, squat bodies, and often a thickly-furred tail. They have short limbs and robust claws that are well-suited for digging. Spotted skunks (Spilogale) are the smallest members of this family, weighing between 200 g and 1 kg. Hog-nosed skunks (Conepatus) reach the largest sizes (up to 4.5 kg).

Reproduction

Generally, skunks are not territorial, and individuals of many species regularly den with conspecifics. During the mating season, males of some species may monopolize several females (e.g. Mephitis mephitis), chasing other males away when they approach. Even when males do not actively defend a group of females, male home ranges often overlap with those of females indicating that individual males may mate with several females in a season.

Little is known about the breeding biology of stink badgers.

Skunks are seasonal breeders; typically, the breeding season lasts two to three months, but the time of the breeding season varies among species, and within species according to geographic location.

Skunks’ gestation period varies among species. In Mephitis and Conepatus, gestation lasts 2 to 3 months. Spilogale gracilis undergoes delayed implantation, in which the fertilized egg does not implant into the uterine wall for a prolonged period of time. Spilogale putorius also exhibits delayed implantation, but only in the northern part of its range. Gestation times (including delayed implantation) in these species can last 250 days or more. Delayed implantation is more typical of species and or populations that live in seasonal climates.

Skunks generally give birth to 2-10 altricial young per year in a single litter. The young are weaned after about two months and become sexually mature late in their first year of life.

Little is known about parental care in stink badgers. Being mammals, females must invest some care before the young are weaned.

Skunks are born in an altricial state, without fur and with their eyes closed. Although the stink glands are full at birth, young cannot use them in defense until after the first week of life, and thus rely on the mother for full protection from predators. The young are weaned after about two months and can begin foraging on their own. Young will share a den with their mothers, and perhaps other conspecifics. Den sharing is especially important during the winter in northern areas to increase survival.

Lifespan/Longevity

First-year skunks suffer high mortality (~ 50% – 70%) as a result of predation and disease. Those that survive can live up to 7 years in the wild, although 5 to 6 years is more typical, and up to 10 years in captivity.

Behavior

Members of the family Mephitidae are perhaps most familiar to people because of their conspicuous antipredator behavior. All mephitids can project a sticky, foul-smelling secretion from their anal scent glands in order to deter a potential threat. Stink badgers can spray over one meter, whereas some skunks (e.g. Mephitis mephitis) can spray an attacker at distances over 6 meters. When confronted with a presumed threat, skunks first face the threat, raise their tails with hair standing on end, and might also stomp on the ground. Skunks may even stand on their forepaws in a “handstand” as they face their attacker. If sufficiently provoked, they will bend their bodies in a U-shape, aiming their hindquarters at the threat and spraying fluid. Typically, skunks aim for a predator’s eyes, which are especially sensitive to the fluid. In addition to spraying attackers, some skunks (e.g., Spilogale putorius) climb trees to avoid danger.

Skunks and stink badgers are nocturnal. They spend the daytime hours in burrows or hollow logs, and forage in the evenings for vegetation, insects, worms, and small vertebrates. In seasonal climates, skunks remain in their dens during the winter months. While they do not enter deep hibernation, they do subsist mainly on fat reserves. Communal dens help skunks conserve energy in the winter.

Skunks are not typically aggressive towards each other, or to heterospecifics. Home ranges typically overlap, and males of some species only actively defend females during the mating season. Although skunks generally forage alone, they may den in groups of several individuals, or even with other species. In many cases, adult males den by themselves or only with females.

Communication and Perception

Skunks are generally not vocal, but sometimes communicate with grunts, growls, and hisses. Olfaction is probably an important part of communication, especially during the mating season. Skunks are not territorial, so do not need to mark territories. Skunks have elaborate visual displays to ward off potential predators, which include holding the tail and body erect, standing on the forepaws, and stomping the ground.

Food Habits

Members of the family Mephitidae are omnivorous, but a large proportion of their diet consists of animal material. Skunks and stink badgers eat a variety of invertebrates such as worms and insects. They also eat small vertebrates such as rodents, lizards, snakes, birds and eggs. Mephitids forage nocturnally, rooting for and digging up prey as they wander through their home range. In northern areas, skunks greatly increase their fat reserves during the fall. During the winter months these skunks spend most of their time sleeping in dens, but will emerge to forage on warmer days.

Predation

Although their scent gland secretions are a potent deterrent to predators, mephitids are at risk of predation. This is especially true for young skunks. When they are out of their burrows, skunks remain relatively conspicuous and depend on their warning coloration to deter attackers. Known predators of skunks and stink badgers are larger carnivores such as coyotes, foxes, pumas, civets, American badgers, and lynx. Birds of prey, having less well-developed olfaction than mammals, are less susceptible to the skunks’ odor, although being sprayed in the eyes is a risk. Avian predators may include eagles and owls. Great horned owls (Bubo virginianus) are known to prey on skunks.

Canidae is a biological family of caniform carnivorans, colloquially referred to as dogs, and constitutes a clade. A member of this family is also called a canid. The Canidae are known as canines, and include domestic dogs, wolves, coyotes, raccoon dogs, foxes, jackals and other species.

Wild canids are native to all continents except Australasia and Antarctica, and also occur as feral (human-introduced) in New Guinea and Australia. They inhabit a wide range of different habitats, including deserts, mountains, forests, and grasslands. They vary in size from the fennec fox, which may be as little as 24 cm in length and weigh 0.6 kg, to the gray wolf, which may be up to 160 cm long, and can weigh up to 79 kg. Only a few species are arboreal—the gray fox, the closely related island fox and the raccoon dog habitually climb trees.

Primarily medium-sized flesh eaters, canids are more omnivorous than many carnivores, taking as food invertebrates, plant matter, and carrion as well as the prey they kill themselves. They are adapted more for endurance than for speed, and they catch prey by pursuit over long distances in relatively open terrain until the prey tires. Kills are made by grabbing for the nape of neck and tackling the prey to the ground. The neck grab is followed by a violent shake, which may dislocate the neck of the prey. Large prey may be immobilized by biting into the soft parts of the underbelly, often resulting in disembowelment and death from shock. Sense of smell is acute and appears to be critical to these animals, as is hearing, but sight is less developed.

All canids have a similar basic form, as exemplified by the gray wolf, although the relative length of muzzle, limbs, ears, and tail vary considerably between species. With the exceptions of the bush dog, the raccoon dog and some domestic dog breeds, canids have relatively long legs and lithe bodies, adapted for chasing prey. The tails are bushy and the length and quality of the pelage vary with the season. The muzzle portion of the skull is much more elongated than that of the cat family. The zygomatic arches are wide, there is a transverse lambdoidal ridge at the rear of the cranium and in some species, a sagittal crest running from front to back. The bony orbits around the eye never form a complete ring and the auditory bullae are smooth and rounded. Females have three to seven pairs of mammae.

All canids are digitigrade, meaning they walk on their toes. The tip of the nose is always naked, as are the cushioned pads on the soles of the feet. These latter consist of a single pad behind the tip of each toe and a more-or-less three-lobed central pad under the roots of the digits. Hairs grow between the pads and in the arctic fox the sole of the foot is densely covered with hair at some times of the year. With the exception of the four-toed African wild dog (Lycaon pictus), five toes are on the forefeet, but the pollex (thumb) is reduced and does not reach the ground. On the hind feet are four toes, but in some domestic dogs, a fifth vestigial toe, known as a dewclaw, is sometimes present, but has no anatomical connection to the rest of the foot. In some species, slightly curved nails are non-retractile and more-or-less blunt while other species have sharper, partially-retractile claws.

The canine penis contains a baculum and a structure called the bulbus glandis that expands during copulation, forming a copulatory tie that lasts for up to an hour. Young canids are born blind, with their eyes opening a few weeks after birth. All living canids (Caninae) have a ligament analogous to the nuchal ligament of ungulates used to maintain the posture of the head and neck with little active muscle exertion; this ligament allows them to conserve energy while running long distances following scent trails with their nose to the ground. However, based on skeletal details of the neck, at least some of the Borophaginae (such as Aelurodon) are believed to have lacked this ligament.

Dentition

Dentition relates to the arrangement of teeth in the mouth, with the dental notation for the upper-jaw teeth using the upper-case letters I to denote incisors, C for canines, P for premolars, and M for molars, and the lower-case letters i, c, p and m to denote the mandible teeth. Teeth are numbered using one side of the mouth and from the front of the mouth to the back. In carnivores, the upper premolar P4 and the lower molar m1 form the carnassials that are used together in a scissor-like action to shear the muscle and tendon of prey.

Canids use their premolars for cutting and crushing except for the upper fourth premolar P4 (the upper carnassial) that is only used for cutting. They use their molars for grinding except for the lower first molar m1 (the lower carnassial) that has evolved for both cutting and grinding depending on the canid’s dietary adaptation. On the lower carnassial, the trigonid is used for slicing and the talonid is used for grinding. The ratio between the trigonid and the talonid indicates a carnivore’s dietary habits, with a larger trigonid indicating a hypercarnivore and a larger talonid indicating a more omnivorous diet. Because of its low variability, the length of the lower carnassial is used to provide an estimate of a carnivore’s body size.

A study of the estimated bite force at the canine teeth of a large sample of living and fossil mammalian predators, when adjusted for their body mass, found that for placental mammals the bite force at the canines was greatest in the extinct dire wolf, followed among the modern canids by the four hypercarnivores that often prey on animals larger than themselves: the African wild dog, the gray wolf, the dhole, and the dingo. The bite force at the carnassials showed a similar trend to the canines. A predator’s largest prey size is strongly influenced by its biomechanical limits.

Most canids have 42 teeth, with the following dental formula: 3/3, 1/1, 4/4, 1-2/2-3. The bush dog has only one upper molar with two below, the dhole has two above and two below. and the bat-eared fox has three or four upper molars and four lower ones. The molar teeth are strong in most species, allowing the animals to crack open bone to reach the marrow.

Social behavior

Almost all canids are social animals and live together in groups. In general, they are territorial or have a home range and sleep in the open, using their dens only for breeding and sometimes in bad weather. In most foxes, and in many of the true dogs, a male and female pair work together to hunt and to raise their young. Gray wolves and some of the other larger canids live in larger groups called packs. African wild dogs have packs which may consist of 20 to 40 animals and packs of fewer than about seven individuals may be incapable of successful reproduction. Hunting in packs has the advantage that larger prey items can be tackled. Some species form packs or live in small family groups depending on the circumstances, including the type of available food. In most species, some individuals live on their own. Within a canid pack, there is a system of dominance so that the strongest, most experienced animals lead the pack. In most cases, the dominant male and female are the only pack members to breed.

Canids communicate with each other by scent signals, by visual clues and gestures, and by vocalizations such as growls, barks, and howls. In most cases, groups have a home territory from which they drive out other conspecifics. Canids use urine scent marks to mark their food caches or warn trespassing individuals. Social behavior is also mediated by secretions from glands on the upper surface of the tail near its root and from the anal glands, preputial glands, and supracaudal glands.

Reproduction

Canids as a group exhibit several reproductive traits that are uncommon among mammals as a whole. They are typically monogamous, provide paternal care to their offspring, have reproductive cycles with lengthy proestral and dioestral phases and have a copulatory tie during mating. They also retain adult offspring in the social group, suppressing the ability of these to breed while making use of the alloparental care they can provide to help raise the next generation. Most canid species are spontaneous ovulators, though maned wolves are induced ovulators.

During the proestral period, increased levels of estradiol make the female attractive to the male. There is a rise in progesterone during the estral phase when female is receptive. Following this, the level of estradiol fluctuates and there is a lengthy dioestrous phase during which the female is pregnant. Pseudo-pregnancy often occurs in canids that have ovulated but failed to conceive. A period of anestrus follows pregnancy or pseudo-pregnancy, there being only one oestral period during each breeding season. Small and medium-sized canids mostly have a gestation of 50 to 60 days, while larger species average 60 to 65 days. The time of year in which the breeding season occurs is related to the length of day, as has been shown for several species that have been moved across the equator and experiences a six-month shift of phase. Domestic dogs and certain small canids in captivity may come into oestrus more often, perhaps because the photoperiod stimulus breaks down under conditions of artificial lighting. Canids have an oestrus period of 1 to 20 days, lasting one week in most species.

The size of a litter varies, with from one to 16 or more pups being born. The young are born small, blind and helpless and require a long period of parental care. They are kept in a den, most often dug into the ground, for warmth and protection. When the young begin eating solid food, both parents, and often other pack members, bring food back for them from the hunt. This is most often vomited up from the adult’s stomach. Where such pack involvement in the feeding of the litter occurs, the breeding success rate is higher than is the case where females split from the group and rear their pups in isolation. Young canids may take a year to mature and learn the skills they need to survive. In some species, such as the African wild dog, male offspring usually remain in the natal pack, while females disperse as a group and join another small group of the opposite sex to form a new pack.

Bears are carnivoran mammals of the family Ursidae. They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout most of the Northern Hemisphere and partially in the Southern Hemisphere. Bears are found on the continents of North America, South America, and Eurasia. Common characteristics of modern bears include large bodies with stocky legs, long snouts, small rounded ears, shaggy hair, plantigrade paws with five nonretractile claws, and short tails.

Bears occur in nearly all terrestrial habitats throughout their range, from Arctic tundra and polar ice floes to tropical and temperate forests, mountains, grasslands, and deserts. Although some bear species occur in arid areas, proximity to water is important. Bears are most abundant and diverse in temperate and boreal regions. Most species are habitat generalists, changing preferred foods, activity patterns, and denning quarters with local conditions. Ailuropoda melanoleuca, however, is found primarily in the montane bamboo forests of southern China.

Physical Description

Bears are large, robustly built animals. The smallest species, Helarctos malayanus ranges in size from 25 to 65 kg, the largest individuals can weigh up to 800 kg (Ursus maritimus). Males are larger than females, sometimes more than twice their size. Bears have small, rounded ears, small eyes, and very short tails. Most species have long, rough fur, and the hairs that make it up are generally unicolored (rather than being agouti, the common pattern among mammals). Sun bears have a smooth coat. Most bears are brown, black, or white; some have striking white marks on the chest or face. Giant pandas are well-known for their distinctive bands of black and white fur. Bear skulls are massive, with unspecialized incisors, elongate canines, reduced premolars, and bunodont cheek teeth. All bear species possess robust, recurved, non-retractile claws that they use for digging and ripping. The feet of bears are plantigrade, and most have hairy soles, although tree climbing bears, such as Helarctos, have naked soles. There are five digits on each foot. Giant pandas (Ailuropoda melanoleuca) have an additional, opposable feature of the forepaws, sometimes called a panda’s “thumb”. It is not a true digit but a pad-covered enlargement of the radial sesamoid bone. Pandas use this opposable structure to manipulate bamboo.

The skulls of bears are elongated. They have an alisphenoid canal, and the paroccipital processes are large and not fused to the bullae, which are not enlarged. Curiously, the lacrimal bone of bears is vestigial. Their cheekteeth are bunodont, and the carnassials are flattened and specialized for crushing, not secodont. The incisors are unspecialized; the canines are long and slightly hooked; and the first three premolars are small and weakly developed if present at all. The dental formula is 3/3, 1/1, 3-4/4, 2/3 = 40-42.

Reproduction

Male and female bears generally associate only briefly for mating. Males monitor the estrus condition of females in their home range and will remain close for a few days when females are receptive. Multiple mating is practiced by both sexes.

Bears give birth to 1 to 4 young, usually 2, at intervals of 1 to 4 years. There is evidence of delayed implantation in all species. Gestation lengths ranging from 95 to 266 days, with implantation being delayed from 45 to 120 days. Actual gestation lengths may be closer to 60 to 70 days. Births in temperate species occur during the winter when the female is dormant. The cubs nurse during the dormant period and the entire metabolic demands of the female must be met by her fat reserves. Births in Helarctos malayanus may occur at any time of the year. Sexual maturity occurs at from to 3 to 6.5 years old, usually occurring later in males. Growth continues after sexual maturity. Males may not reach their adult size until 10-11 years old. Females reach adult sizes usually around 5 years old.

Females give birth to their young in protected areas, often a den of some kind, until they are capable of getting around well, at several months of age. Bears are very small when born, from 90 (Ailuropoda melanoleuca) to 680 (Ursus arctos) g at birth. They are born with their eyes and ears closed and are either naked or with only a fine layer of fur. Cubs grow rapidly, polar bears go from 600 g at birth to 10 to 15 kg within 4 months. Weaning occurs from 3.5 (Ursus thibetanus) to 9 (Ailuropoda melanoleuca) months. Young stay with their mother for up to 3 years, but young of most species disperse after 18 to 24 months. Females are very protective of their young and it is likely that cubs learn about obtaining food and shelter during their extended juvenile time with their mother.

Lifespan/Longevity

Bears are long-lived if they survive their first few years of life. Most mortality occurs in young cubs or dispersing juveniles as a result of food stress. Pre-weaning cub mortality was estimated at 10-30% in polar bears and sub-adult mortality at between 3 and 16%. In American black bears in Alaska, sub-adult mortality was estimated at 52 to 86%. Estimates of longevity in the wild are as high as 25 years. Captive animals have been known to live to 50 years or more (Ursus arctos).

Behavior

Bears are generally solitary, with the exception of mothers with their young. Bears are most often nocturnal or crepuscular, but may be active during the day as well. Polar bears (Ursus maritimus) are primarily diurnal. Bears generally take advantage of shelters, such as caves, hollow logs, and cavities in tree roots, as dens. Helarctos malayanus individuals spend much of their time in trees and build platforms for resting. Bears tend to move relatively slowly, with a shuffling, plantigrade gait, but are capable of running quickly when necessary, standing and walking on the rear two feet, and climbing. Polar bears (Ursus maritimus) are excellent swimmers and sun bears (Helarctos malayanus) are quite arboreal. Most bears move throughout a large range in order to meet their metabolic needs. Polar bear females migrate off of pack ice in late fall to give birth to their young in dens.

Some temperate bear species undergo extended periods of torpor during winters, retreating to underground burrows or caves to escape from temperature fluctuations. They become lethargic and metabolize fat reserves accumulated during the summer and fall. Some physiologists do not consider this a true state of hibernation, as body temperatures do not drop substantially and bears can be readily roused from this state. Others consider this distinction a semantic one and some researchers have proposed that this is a true hibernation because heart rates drop to almost half the normal rate. Bear species that undergo this form of hibernation often give birth during their winter sleep.

Communication and Perception

Vision and hearing in bears is not well-developed, but they have a keen sense of smell and use their sensitive lips to locate and maneuver food. Ursus americanus has color vision and has been demonstrated using vision to distinguish food items at close range. Little is known about communication in bears, but grunts, moans, and roars are known from most species. Cubs may be especially vocal, uttering “woofs” and shrill howls when distressed. “Chuffing” is used as a greeting in Ursus arctos. Chemical cues may be used by males in locating receptive females. Home range boundaries, individual identity, and sexual condition may be advertised, both visually and chemically, by tree-scratching and by urinating and defecating on boundary trails.

Food Habits

Bears are omnivorous and opportunistic. Specific food types may vary by habitat or season. For example, North American brown bears (Ursus arctos) may rely extensively on fruits and insect larvae throughout the year, or may prey extensively on calves during ungulate breeding seasons and on migrating fish. Most species eat primarily fruits and insect larvae but will include vertebrates when they can, carrion, honey, forbs and grasses, seeds, nuts, tubers, fish, and eggs. Bears use their formidable strength, massive forelimbs, and robust claws to tear apart logs and capture prey. Giant pandas (Ailuropoda melanoleuca) are dietary specialists, eating primarily bamboo stems and shoots, but will also include small vertebrates, insects, and carrion in their diet. Polar bears (Ursus maritimus) are the most carnivorous species, preying mainly on seal species, but including fish, small mammals, birds and their eggs, and will scavenge carcasses of whales, walruses, and seals.

Predation

Once bears reach their adult size it is unlikely that they will be subject to predation. Cubs are at risk of predation from conspecific bears, sympatric bear species, and other large predators, such as large cats and canids. Female bears are aggressive in defense of their young.

Eupleridae is a family of carnivorans endemic to Madagascar and comprising 7 known living species in seven genera, commonly known as euplerids, Malagasy mongooses or Malagasy carnivorans. The best known species is the fossa (Cryptoprocta ferox), in the subfamily Euplerinae. Species in the family Eupleridae are restricted to the island of Madagascar. Euplerids live in a variety of habitats, from humid forests, marshes, bogs, and swamps, to deserts and savannahs.

Physical Description

Aside from molecular synapomorphies, euplerids have few traits in common. They tend to have slender bodies with relatively small heads and pointed rostra, although fossas (Cryptoprocta ferox) are more cat-like in appearance, with blunt snouts. Head and body length ranges from 250 mm in Mungotictis and Salanoia to 800 mm in adult male Cryptoprocta. The thick, soft pelage is gray or brown, and spotted or striped in all but Eupleres and Cryptoprocta. The foot posture is plantigrade or digitigrade.

Reproduction

Mating systems in Eupleridae vary, as social structure varies from species to species. Fossas form monogamous pairs, while species in the genera Galidia, Mungotictis, and Salanoia are either found alone or in pairs, suggesting that they are monogamous within, but not across, breeding seasons. Species in the genera Eupleres and Galidictis live alone, in pairs, or in small family groups, which also might indicate monogamy. Mungotictis individuals live in small groups with several adults of each sex, but it is not known whether all of the adults within a group breed. Cryptoprocta individuals are strictly solitary, suggesting a polygynous or polygynandrous mating system.

Euplerids have definite breeding seasons, which vary by species and last anywhere from two to eight months. Gestation lasts around three months. Usually there are just one or two young per litter, though Cryptoprocta can have up to four. Weaning takes place between two and four and a half months.

Like all eutherian mammals, euplerid females nuture their young through a placenta until the young are born. They then provide their offspring with milk for two to four and a half months. Females of some genera, such as Cryptoprocta, select dens in which to bear and nurse their young. Mungotictis individuals live in family groups of several adults, juveniles, and young; thus, offspring have an association with their parents beyond weaning.

Euplerid lifespans in the wild are unknown. Cryptoprocta holds the longevity record in captivity, at 20 years.

Behavior

Euplerids exhibit a range of lifestyles, from diurnal to nocturnal, and from arboreal to terrestrial. When they are not active, they shelter in protected spots, such as tree hollows, crevices, burrows, or caves. Locomotion is plantigrade or digitigrade. Mungotictis decemlineata have partially webbed toes and are good swimmers. As mentioned above, social habits range from strictly solitary to group living. Some species (Fossa and Cryptoprocta) vigorously defend territories against other pairs or individuals.

Communication and Perception

Like other carnivores, euplerids can perceive visual, acoustic, chemical, and tactile signals. Communication is through scent in the form of glandular secretions and through a variety of cries, groans, and other vocalizations.

Food Habits

Euplerids are primarily carnivorous, consuming small mammals, birds, reptiles, frogs, insects, crustaceans, and other invertebrates. Eupleres goudotii is specialized for eating intertebrates such as earthworms. Fossa fossana and Galidia elegans may include some fruit in their diets in addition to animal matter.

Predation

No information is available on the specific predators of euplerids, besides humans and domestic dogs, both of which are not native to Madagascar. Cryptic coloration in the form of spots and stripes on neutral backgrounds probably conceals most species well. Eupleres goudotii is known to either run or freeze when disturbed, and Cryptoprocta ferox releases a foul-smelling substance from its anal glands when it is alarmed. Large birds of prey or large snakes are potential predators.