The Canada lynx (Lynx canadensis) or Canadian lynx is one of the four living species in the genus Lynx. It is a medium-sized wild cat characterized by long, dense fur, triangular ears with black tufts at the tips, and broad, snowshoe-like paws. Its hindlimbs are longer than the forelimbs, so its back slopes downward to the front. The Canada lynx stands tall at the shoulder and weighs between . It is a good swimmer and an agile climber.
The Canada lynx was first described by Robert Kerr in 1792. Three subspecies have been proposed, but their validity is doubted; it is mostly considered a monotypic species. It ranges across Alaska, Canada and northern areas of the contiguous United States, where it predominantly inhabits dense boreal forests. It is a specialist predator and depends heavily on the snowshoe hare (Lepus americanus) for food. This leads to a prey-predator cycle, as the Canada lynx population responds to the cyclic rises and falls in snowshoe hare populations over the years in Alaska and central Canada. The Canada lynx population increases with an increasing hare population; if the hare population decreases in a given area, it moves to areas with more hares and has fewer offspring. The Canada lynx hunts mainly around twilight, or at night, when the snowshoe hare tends to be active. The Canada lynx waits for the hare on specific trails or in "ambush beds", then pounces on it and kills it by a bite on its head, throat or the nape of its neck. Individuals, particularly of the same sex, tend to avoid each other, forming "intrasexual" territories. The mating season is roughly a month long from March to early April. After a gestation of two to three months, females give birth to a litter of one to eight kittens, which are weaned at the age of 12 weeks.
Given its abundance throughout the range and lack of severe threats, the Canada lynx has been listed as Least Concern on the IUCN Red List. It is regularly trapped for the international fur trade in most of Alaska and Canada but is protected in the southern half of its range due to threats such as habitat loss.
Taxonomy The scientific name Felis lynx canadensis was proposed by Robert Kerr in 1792 who described a lynx from Canada. In the late 19th century, several lynx zoological specimens were described: Lynx subsolanus was proposed by Outram Bangs in 1897 for a lynx skin and skull collected near Codroy, Newfoundland. Lynx canadensis mollipilosus was proposed by Witmer Stone in 1900 who described a skull and a dark brown skin of a male lynx killed near Wainwright, Alaska.
The placement of the Canada lynx in the genus Lynx was supported by Gerrit Miller in 1912. Until as late as the early 2000s, scientists were divided over 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. It was recognized by Wallace Christopher Wozencraft in 2005 as a valid Lynx species along with the bobcat (L. rufus), the Eurasian lynx (L. lynx) and the Iberian lynx (L. pardinus). Wozencraft recognized three subspecies of the Canada lynx: L. c. canadensis in Canadian mainland L. c. subsolanus in Newfoundland L. c. mollipilosus in Alaska
The validity of the subspecific status of the Newfoundland lynx was questioned in 1975, as results of a study of coat colour, cranial measurements and weights of Canada lynx specimens showed that the standard measurements are not significantly distinct, apart from a few variations like the Newfoundland lynx's darker coat.
In 2017, the Cat Specialist Group considered the Canada lynx a monotypic species, since it shows little morphological or genetic differences.
The lynx population on Newfoundland is thought to have genetically diverged from the mainland Canada lynx around 20,000 to 33,000 years ago following the Last Glacial Period.
Evolution
According to a 2006 phylogenetic study, the ancestor of five extant felid lineages—Lynx, Leopardus, Puma, Felis and Prionailurus plus Otocolobus—arrived in North America after crossing the Bering Strait (mya). Lynx diverged from the Puma, Felis and Prionailurus plus Otocolobus lineages around 2.53–4.74mya. The Issoire lynx (L. issiodorensis), believed to be the ancestor of the four modern Lynx species, probably originated in Africa 4mya and occurred in Europe and northern Asia until it fell to extinction around 1mya. The populations of the Eurasian lynx that reached North America 2.6mya are believed to have initially settled in the southern half of the continent, as the northern part was covered by glaciers. The southern populations gradually evolved into the modern bobcat. Later, when the continent was invaded by the Eurasian lynx for a second time within the last 200,000 years, the populations that settled in the northern part of the continent, now devoid of glaciers, evolved into the Canada lynx. In his 1981 paper, Swedish paleontologist Lars Werdelin noted that the Canada lynx does not appear to have changed much since its first appearance. Canada lynx fossils excavated in North America date back to the Sangamonian and the Wisconsin Glacial Episode. The 2006 study gave the phylogenetic relationships of the Canada lynx as follows:
Characteristics
The Canada lynx is a lean, medium-sized cat characterized by its long, dense fur, triangular ears with black tufts at the tips, and broad, snowshoe-like paws. Like the bobcat, the hindlimbs are longer than the forelimbs, so the back slopes downward to the front. The Canada lynx is sexually dimorphic, with males larger and heavier than females. The lynx is between in total length and stands tall at the shoulder; females range in weight from and males from , though an exceptional male in Pennsylvania weighed . Physical proportions do not vary significantly across the range and are probably naturally selected to allow for survival on smaller prey. The stubby tail is long and has a completely black tip. Skeletal muscles make up 56.5 % of the Canada lynx's body weight.
The long, thick fur, uniformly coloured with little to no markings except on the underside, insulates the lynx in its frosty habitat. The fur is typically yellowish brown, though in Newfoundland it can vary from brown or buff-grey in spring and summer to a greyish shade with a grizzled appearance in winter; the underparts are white and may have a few dark spots. An individual from Alaska was reported to have bluish-grey fur. The fur is generally shorter in summer than in winter. The backs of the ears are brown with a silvery-grey spot at the centre. Black tufts around in length emerge from the tips of the ears, which are lined with black fur. In winter, the hair on the lower cheek becomes longer, giving the impression of a ruffle covering the throat. There are four nipples.
The claws are sharp and fully retractile. The large, broad paws are covered in long, thick fur and can spread as wide as to move quickly and easily on soft snow. Its paws can support almost twice as much weight as a bobcat's before sinking. Both species walk with the back foot typically following the front foot and often do not follow a straight line. The lynx's stride is , while the bobcat's varies between . Canada lynx tracks are generally larger than those of the bobcat; thicker fur may make the toe pads appear less prominent in the snow. In dirt the tracks of the lynx are long and wide, whereas in snow they are bigger ( long and wide). The warm coat, wide paws and long legs serve as adaptations for the lynx to navigate and hunt efficiently in snow.
The Canada lynx has 28 teeth. The dental formula is . The deciduous dentition is , as the young do not have molars. The four long canines are used 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. To use its carnassials, the lynx 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 the bite goes as deeply as possible into the prey.
The Canada lynx can be told apart from the bobcat by its longer ear tufts, broader paws, shorter tail with a fully black tip, longer legs and the fewer markings and greyer shade of the coat. 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.
Distribution and habitat
The Canada lynx occurs predominantly in the dense boreal forest of Canada, and its range strongly coincides with that of the snowshoe hare. In the past, the lynx occurred in the northern United States in 24 states, possibly southward to the Rocky Mountains in New Mexico and northward to the tree line in the Arctic through coniferous forests in Alaska and Canada. The lynx continues to occur in its former range in most of Alaska and Canada. In the United States, the Canada lynx occurs in the Blue Mountains and the Cascade Range in the Pacific Northwest, the Rocky Mountains, the northern Great Lakes region (in Minnesota and Michigan's Upper Peninsula) and northern New England (in New Hampshire, Maine and Vermont). The lynx was successfully reintroduced in Colorado starting in 1999, after being extirpated from the state in the 1970s. Canada lynxes generally avoid open areas despite good prey availability; they face difficulty surviving in heavily logged areas and on agricultural land, though they can thrive well in deforested areas that have been left to regenerate at least fifteen years. Canada lynxes have been recorded up to an elevation of . It is considered extirpated in New York, Pennsylvania, Massachusetts, Nevada, Indiana, and Ohio. In February 2022, a picture of a large male Canada lynx was taken by a hunter in the southern Gros Ventre Range of Wyoming after his hounds treed the cat, making it the first confirmed sighting in the state since 2012.
Ecology and behaviour 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 daily, moving at , to procure prey. These lynxes are good swimmers; one account records a Canada lynx swimming across the Yukon River. Canada lynxes are efficient climbers, and will dodge predators by climbing high up in trees, but they hunt only on the ground. These lynxes are primarily solitary, with minimal social interaction except for the bond between mothers and female offspring, 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 of bears, bobcats, cougars and mustelids. Intraspecific aggression and consequent cannibalism are rare, but may be more common when food is scarce.
Home ranges
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 in 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 , while those based on radio telemetry have given the area between . Like other cats, Canada lynxes scent-mark their ranges by spraying urine and depositing feces on snow or tree stumps and other prominent sites in and around their range.