A grainy cellphone video of a leggy black cat sauntering through a residential yard near Whitehorse in August of 2020 was a lucky discovery for a Yukon biologist. The footage clearly reveals the distinctive pompom tail and oversized, cartoon-like hindquarters of a Canada lynx, a relatively common year-round resident of the boreal forest across the Canadian north. Only in this case, the lynx’s coat was soot-coloured, a first according to Yukon government senior wildlife biologist Thomas Jung.
Jung documented the sighting in a recent paper in Mammalia Journal, exploring the significance of variation in coat colour as a positive or negative trait in wildlife. Canada lynx are typically “silver grayish in winter and reddish brown in summer with dark spots,” Jung writes, “[with] black hairs on the tips of their tails and ears.” Paler-coloured individuals are occasionally observed, Jung adds, “suggestive of partial albinism.”
Wider variations in colour occur in other mammals, such as the cream-coloured “Spirit Bear” variation of black bears on the British Columbia coast, with possible benefits such as temperature regulation or being better camouflaged. Jung says black bears in the Yukon are often tan or cinnamon-coloured, to better blend in with the region’s sparse forests. “It comes down to which colour works best in the habitat,” he says.
So-called “melanism” is caused by a genetic mutation causing the individual to produce an excess of melanin, a dark-coloured pigment. Dark-coloured big cats occur in humid tropics, where they may blend in better with the surrounding jungle. Jung’s literature review uncovered accounts of black ground squirrels sighted in burned over patches of boreal forest and similar occurrences in bobcats in New Brunswick, suggesting this melanism enables individuals to be camouflaged with charred timber.
The melanistic lynx spotted near Whitehorse was the first record of such for the species, possibly for good reason. Jung doesn’t expect to see black lynx flourishing in the Canadian subarctic where a dark-coloured feline would be at a distinct disadvantage when stalking hares in the snowy winter. “It doesn’t matter whether you’re in the Yukon or northern Ontario,” he says, “lynx are grayish white because it works. To stalk and ambush their prey they need to be well camouflaged.”