|Distribution of Canada Lynx, 2016|
The Canada lynx (Lynx canadensis) is a lynx species native to North America. It ranges across Canada and Alaska extending into the United States portion of the Rocky Mountains. It has been listed as Least Concern on the IUCN Red List since 2002.
With a dense silvery-brown coat, ruffed face and tufted ears, the Canada lynx resembles the other species of the mid-sized feline genus Lynx. It is slightly larger than a bobcat, with which it shares parts of its range, and over twice the size of the domestic cat.
In his 1792 work The Animal Kingdom, Scottish scientific writer Robert Kerr described a lynx from Canada, giving it the name Felis lynx canadensis. The taxonomy of the Canada lynx remained disputed through the 20th and early 21st centuries. In 1912, American zoologist Gerrit Miller placed the Canada lynx under the genus Lynx, with the name L. canadensis. Till as late as the early 2000s, scientists were divided on whether Lynx should be considered a subgenus of Felis, or a subfamily itself; some even doubted if the Canada lynx should be considered a species on its own. American zoologist W. C. Wozencraft revised the classification of Carnivora in 2005, and recognized the Canada lynx as a species under Lynx, along with the bobcat (L. rufus), the Eurasian lynx (L. lynx) and the Iberian lynx (L. pardinus). In 2017, the Cat Classification Task Force of the IUCN Cat Specialist Group revised felid taxonomy, considering the Canada lynx a monotypic species.
A study of the differences (in factors such as coat colour, cranial measurements and weights) between the mainland and Newfoundland forms showed that apart from a few variations (for instance, the Newfoundland lynx features a darker coat than the mainland subspecies), the standard measurements are not significantly distinct. The researchers noted that, given that only a few differences exist between the two forms, the Newfoundland lynx appears to have diverged only recently from the mainland form. The lack of appreciable subspecific distinctions led them to doubt the identity of the Newfoundland lynx as a separate subspecies. A study in 2019 estimated the Newfoundland lynx to have diverged from the mainland lynx around 20,000 to 33,000 years ago following the last glaciation.
According to a 2006 study based on genetic analysis, the ancestor of five felid lineages - Lynx, Leopardus, Puma, Felis and Prionailurus plus Otocolobus - arrived in North America after crossing the Bering Strait 8.5-8 mya. Lynx diverged from the Puma, Felis and Prionailurus plus Otocolobus lineages around 3.24 mya. The Issoire lynx (L. issiodorensis), that probably originated in Africa 4 mya and occurred in Europe and northern Asia until it became extinct around 1 mya, is believed to be the ancestor of the four modern species of Lynx. A 1987 study suggested that the populations of the Eurasian lynx that reached North America 20,000 years ago initially moved toward the southern half of the continent, as the northern part was covered by glaciers. The southern populations gradually evolved into the modern bobcat (L. rufus). Later, when the continent was invaded by the Eurasian lynx for a second time, the populations that settled in the northern part of the continent, now devoid of glaciers, evolved into the Canada lynx. The 2006 study gave the phylogenetic relationships of the Canada lynx as follows:
The Canada lynx is a medium-sized cat, similar in many ways to the bobcat. This lynx is between 80 and 100 centimetres (31 and 39 in) in head-and-body length, stands 48-56 centimetres (19-22 in) tall at the shoulder and weighs 5-18 kilograms (11-40 lb). At roughly half the size of the Eurasian lynx, physical proportions do not vary significantly across its range and are probably naturally selected to allow the animal to survive on smaller prey. The Canada lynx is sexually dimorphic, with males larger and heavier than females. Like the bobcat, the Canada lynx has forelimbs shorter than the hindlimbs, so that the back appears to be sloping downward to the front. The stubby tail, typical of lynxes, measures 5-15 centimetres (2.0-5.9 in).
The coat is generally yellowish brown (though the back is sometimes grey), and can change colour seasonally. The dense, long fur insulates it in its frosty habitat. Although no melanistic or albinistic forms of the Canada lynx are known, "blue" lynxes have been reported from Alaska. Black hair tufts (4 centimetres (1.6 in) long), a feature common to all lynxes, emerge from the tips of the ears, which are lined with black. In winter, the hair on the lower cheeks grow so long that it appears to form a ruffle covering the throat. Some dark spots can be seen on the underbelly, where the fur is long and white (sometimes with a hint of buff). There are four nipples. The coat is short and reddish brown to greyish in summer, but becomes notably longer and greyer in winter, with a mix of greyish brown and buff hairs; the spots may become more distinct in summer. The tail is marked with dark rings and, unlike the tail of the bobcat, terminates in a fully black tip. The paws, covered in long and thick fur, can support nearly double the weight the paws of a bobcat can bear.
The Canada lynx has 28 teeth, same as in other lynxes but unlike other felids, with four long canines for puncturing and gripping. The lynx can feel where it is biting the prey with its canines because they are heavily laced with nerves. It also has four carnassial teeth that cut the meat into small pieces. In order for the lynx to use its carnassials, it must chew the meat with its head to its side. There are large spaces between the four canines and the rest of the teeth, and the second upper premolars are absent, to ensure that the bite goes as deeply as possible into the prey. The claws are sharp and completely retractable (capable of being drawn within). The paws, broadened by the wide-spaced metatarsals, can spread as wide as 10 centimetres (3.9 in) and allow the lynx to move fast and with ease on the snow. The spoor is more distinct in hard snow than in mud, though the toes are not clearly visible in deep snow.
The Canada lynx differs from the bobcat in having longer ear tufts, a greyer and less red coat, less distinct spotting on the coat, a slightly shorter tail completely black on the tip rather than only on the upper side, and larger paws. The bobcat is generally smaller than the Canada lynx, but in areas where they are sympatric the bobcat tends to be larger and may still be confused with the Canada lynx. The caracal resembles the lynxes in having similar tufts on the ears.
Canada lynx tracks may show traces of the fur dragging in the snow around the track, and the toe pads may not be as clearly visible as a bobcat's due to the thick fur. Both species walk with the back foot typically following the front foot, and often do not follow a straight line path. The stride, or the separation between footprints of the same foot, is 30-46 cm (12-18 in) for the lynx, while that of the bobcat varies between 13 and 41 cm (5 and 16 in). Lynx tracks are generally larger than those of the bobcat, with significantly greater impression of fur observable. In dirt the tracks of the lynx are 7.6-9.5 cm (3-3.75 in) long and 8.9-11.4 cm (3.5-4.5 in) wide, whereas in snow they are bigger (11 cm (4.5 in) long and 13 cm (5 in) wide). The broad paws provide good support on the soft snow.
The Canada lynx tends to be nocturnal like its primary prey, the snowshoe hare. Nevertheless, activity may be observed during daytime. The lynx can cover 8-9 kilometres (5.0-5.6 mi) every day to procure prey, moving at 0.75-1.46 km/h (0.47-0.91 mph). Lynxes are good swimmers; one account records a lynx swimming two miles across the Yukon River. Canada lynxes are efficient climbers, and will dodge predators by climbing high up on trees; however, they hunt only on land. These lynxes are primarily solitary, with minimal social interaction except for the mother-offspring bond and the temporary association between individuals of opposite sexes during the mating season. Individuals of the same sex particularly tend to avoid each other, forming "intrasexual" territories--a social structure similar to that found in bobcats, cougars, mustelids and ursids. Intraspecific aggression and consequent cannibalism (more common when food is scarce) are rare.
Fishers are known to occasionally hunt Canada lynxes in the northeastern United States; a study in northern Maine identified predation by fishers as the leading cause of Canada lynx mortality over 12 years, though it did not appear to affect population growth in the lynxes.
The Canada lynx is known to host several parasites including Cylicospirura felineus, Taenia species, Toxocara cati, Toxascaris leonina and Troglostrongylus wilsoni. Canada lynxes could have played a role in the transmission of the zoonotic parasite Toxoplasma gondii to the Inuit in North America. A study in 2019 identified a gammaherpesvirus species in the Canada lynx for the first time. The study discovered a novel percavirus, named LcaGHV1, in spleen samples of Canada lynxes from Maine and Newfoundland.
A specialist predator, the Canada lynx depends heavily on snowshoe hares for food. Snowshoe hare populations in Alaska and central Canada undergo cyclic rises and falls--at times the population densities can fall from as high as 2,300/km2 (6,000/sq mi) to as low as 12/km2 (31/sq mi). Consequently, a period of hare scarcity occurs every 8 to 11 years. An example of a prey-predator cycle, the cyclic variations in snowshoe hare populations significantly affect the numbers of their predators--lynxes and coyotes--in the region. When the hare populations plummet, lynxes tend to move to areas with more hares, and tend to not produce litters. In northern Canada, the abundance of lynx can be estimated from the records kept of the number caught each year for their fur; records have been kept by the Hudson's Bay Company and Canadian government since the 1730s. These cycles have been cited as one of the few examples of the Lotka-Volterra predator-prey equations, caused by the interplay of three major factors--food, predation and social interaction. A study involving statistical modelling of the interspecific relations of the snowshoe hare, the plant species it feeds on and its predators (including the Canada lynx) suggested that while the demographics of the lynx depend primarily on the hare, the hare's dynamics depend both on the plant species in its diet and predators, of which the Canada lynx is just one.
Canada lynxes establish home ranges that vary widely in size, depending upon the method of measurement. The two common methods are examining the tracks of the lynx on snow (snow-tracking) and radio telemetry; snow-tracking generally gives smaller sizes for home ranges. Studies based on snow-tracking have estimated home range sizes of 11.1-49.5 km2 (4.3-19.1 sq mi), while those based on radio telemetry have given the area between 8 and 783 km2 (3.1 and 302.3 sq mi). Like other cats, Canada lynxes scent-mark their ranges by spraying urine and depositing faeces on snow or tree stumps and other prominent sites in and around their range.
Males tend to occupy larger ranges than do females; for instance, based on data from a 1980 radio telemetric analysis in Minnesota, the home ranges of males covered 145-243 km2 (56-94 sq mi), while those of females covered 51-122 km2 (20-47 sq mi). The study coincided with an immigration of lynxes into Minnesota, where hares occurred in small numbers. In another radio telemetric study in 1985 in Montana, male home ranges averaged 122 km2 (47 sq mi) and those of females averaged 43.1 km2 (16.6 sq mi). In a study in the southern Northwest Territories, ranges of individuals of opposite sexes were found to overlap extensively, while the ranges of individuals of the same sex hardly coincided. The study suggested that individuals do not show any significant tendency to avoid or mingle with one another, and thus only passively defend their ranges. Female home ranges contract in size when the females have offspring to take care of, and expand to their original size at the time of weaning.
Factors such as availability of prey (primarily snowshoe hare), density of lynxes and the topography of the habitat determine the shape and size of the home range. Studies have tried to correlate the abundance of snowshoe hares in an area with the sizes of lynx home ranges in that area. A 1985 study showed that the mean size of home ranges trebled--from 13.2 to 39.2 km2 (5.1 to 15.1 sq mi)--when the density of hares fell from 14.7 to 1/ha (5.95 to 0.40/acre). However, a few other studies have reported different responses from lynxes at times of prey scarcity; some lynxes do not show any changes in their ranges, while others may resort to hunting in small areas, occupying small home ranges. Canada lynxes generally do not leave their home ranges frequently, though limited prey availability can be a factor powerful enough to cause lynxes to disperse or expand their ranges.
A genetic study showed that lynxes at the periphery of a population, given their smaller size and higher susceptibility to variations in the range, face more difficulty in genetic exchange and hence show lower heterozygosity.
The Canada lynx preys primarily and almost exclusively on the snowshoe hare; these hares comprise 35 to 97 percent of their diet, and the proportion varies by the season and the abundance of hares. However, at times when the numbers of the hare drop, lynxes will include other animals in their diet - such as ducks, grouse, moles, ptarmigan, red squirrels, voles and young ungulates (Dall's sheep, mule deer and caribou) - though snowshoe hares continue to be the primary component. The Canada lynx tends to be less selective in summer and autumn, adding small mammals as a minor component of their diet besides the hare. The reason behind this is unclear--it could be due to greater abundance of alternate prey, or reduced success in hunting hares. A study in Alaska found that lynxes played a role in the decrease in populations of red fox, caribou and Dall's sheep when hares were very low in number. They ingest 600-1,200 grams (21-42 oz) of food everyday. Lynxes have also been reported feeding occasionally on succulent sedges and grasses.
Both coyotes and Canada lynxes are major predators of the snowshoe hare. A study showed that compared to lynxes, the feet of coyotes sink deeper in the snow due to their smaller size and hence a bigger body mass-foot area ratio, prompting them to ambush their prey instead of chasing it like lynxes often do. A study of the two species in southwest Yukon Territory showed that when the numbers of the hare increased, both predators killed more hares than were necessary for their subsistence; lynxes need to kill 0.4 to 0.5 hare per day to meet their energy requirements, but were observed to kill 1.2 hares per day during this period. Coyotes, with a success rate of 36.9%, emerged as more successful hunters than lynxes (though this may have been caused due to the greater number of adult coyotes in the studied population), that succeeded in 28.7% of their hunts. Lynxes rarely cached their kills, unlike coyotes, and this may have led to incomplete consumption of some kills. During the cyclic decrease in snowshoe hare numbers, both predators hunted for the same time period as they did when hares were abundant, but lynxes killed more hares than they did earlier. Moreover, lynxes supplemented their diet with red squirrels.
Canadian lynxes hunt around twilight or at night, the time when snowshoe hares tend to be active. Lynxes rely on their vision and sense of hearing to locate prey. The lynx will roam or wait (in what researchers often term "ambush beds") on certain trails where snowshoe hares gather, pounce on a hare and kill it by a bite on its head, throat or the nape of its neck. Sometimes a chase of around ten bounds may be necessary to trap the prey. The lynx is assisted by its stereoscopic vision in detecting prey and measuring distances. Staying in cover while hunting helps the lynx conserve energy in its frigid habitat by avoiding unnecessary movement. Young ungulates are given a throat bite to suffocate them to death. The lynx may eat its kill immediately or cache it in snow or leaves to eat it over the next few days. Lynxes will occasionally hunt together, though studies differ on how this affects the hunting success rate compared to when an individual hunts alone. In fact, they may hunt in groups when hares are scarce.Scavenging is common in Canada lynxes; they will take ungulates killed in the cold or by roadkill.
The breeding season in Canada lynx lasts only a month, from March to May, depending on the local climate. Females come into estrus only once during this period, lasting three to five days. The female attracts a mate by repeated calling and leaving some of her urine where the male has marked his territory. Mating can occur six times in one hour. The female will mate with only one male per season, but the male may mate with multiple females.
Gestation lasts around 64 days, so that the young are born in May or early June. Before birth, the female prepares a maternal den, usually in very thick brush, and typically inside thickets of shrubs or trees or woody debris. The dens are generally situated mid-slope and face south or southwest.
Litters comprise one to four kittens, and tend to be much larger when prey is abundant. Moreover, females often do not mate at all when prey is scarce, suggesting a greater degree of reproductive flexibility than in other cats. In lean years, infant mortality may be as high as 95%.
Kittens weigh from 175 to 235 g (6.2 to 8.3 oz) at birth, and initially have greyish buff fur with black markings. They are blind for the first 14 days, and weaned at 12 weeks. When their eyes open, they are bright blue, but as they mature, the colour changes to brown or hazel. The mother brings food to her kittens and allows them to play with it before eating it to hone their hunting skills.
Kittens leave the den after about five weeks, and begin hunting at between seven and nine months of age. They leave the mother at around ten months, as the next breeding season begins, but do not reach the full adult size until around two years old. Females reach sexual maturity at ten months, although they often delay breeding for another year, whereas males reach maturity at two or three years. Canada lynx have been reported to live for up to 14 years in captivity, though the lifespan is likely much shorter in the wild.
The Canada lynx is found in northern and mixed boreal forests across Canada and Alaska. It is, however, absent in the relatively treeless regions of the Great Plains and the northern coasts, which are outside the natural range of the snowshoe hare. Due to human activity, the Canada lynx is extirpated from Prince Edward Island as well as the mainland of Nova Scotia, although there are two known areas of Canada lynx populations in Cape Breton Highlands.
In addition, there are large populations of this lynx in Montana, Idaho, Washington, and Oregon, and a resident population exists in Yellowstone National Park and Medicine Bow National Forest, Wyoming, that extends into the Greater Yellowstone Ecosystem. The Canada lynx is rare in Utah, Minnesota, and New England. The Canada lynx is a threatened species in the contiguous United States.
A Canada lynx was shot near Newton Abbott in the United Kingdom in 1903 after attacking two dogs. The dead lynx was preserved by Bristol Museum and Art Gallery, and scientists identified it after analysis over a century later. They concluded that it had probably been captive for some time, perhaps as an exotic pet or part of a travelling menagerie, but may have survived for a substantial period after escaping. They considered it "the earliest recorded example of an exotic cat on the loose in the UK".
Starting in 1999, the Colorado Division of Wildlife began a program reintroducing a wild lynx population of 96 to Colorado. While showing early signs of promise, biologists say it will take more than a decade to determine whether the program is a success. However, in 2003 lynx den visits identified 16 native-born Colorado lynx, and the next year, 39 new lynx kittens were identified, confirming the possibility of successful reintroduction.
In 2007 several of these lynx were shot and killed by unknown persons. In some cases only the radio tracking collars were found, leading to suspicions of fur poaching; in other cases the animals were shot and the body left intact.
By 2010, after an 11-year effort, the lynx had been successfully reintroduced into Colorado, where it had become extinct in the 1970s. The initial introduction was in the San Juan Mountains in southwestern Colorado, but self-sustaining populations were established throughout the south-central Colorado Rockies as far north as Summit County by 2010. In Colorado the red squirrel is an important secondary food source when snowshoe hares are scarce. Isolated individual lynx have wandered widely from the core area in the Southern Rockies where they were reintroduced, resulting in observation of lynx introduced in Colorado as far away as Iowa, northern Idaho, and eastern Nevada. It was found helpful to rest and feed the animals well before releasing them in prime condition during the spring thaw.
The Canada lynx is trapped for its fur, and has declined in many areas due to habitat loss; however, the IUCN lists them as a species of Least Concern. On March 24, 2000, the U.S. Fish and Wildlife Service issued its Final Rule, which designated the Canada lynx a Threatened Species in the southern-most 48 states.Canada lynx-bobcat hybrids have also been detected at the southern periphery of the current population range for lynx (Maine, Minnesota and New Brunswick), which may limit their recovery in the south.
In January 2018, wildlife officials said that the Canada lynx no longer needed special protections in the United States following measures to preserve their populations.