Why Is Some Wildlife White?
It’s winter and most of the Canadian landscape is blanketed white with snow. So, I figured it was an appropriate time to talk about white-coloured wildlife.
In 2017, photos and a video of white bull moose filmed in Sweden went viral. There is also the famous Seneca white-tailed Deer of New York State, the polar bears of Churchill, Manitoba and the one-of-a-kind Spirit Bear in British Columbia that people travel from afar to witness. The white moose in Sweden (pictured above) was a piebald moose, the Seneca deer in New York are leucistic, polar bears emit white light and the Spirit Bear is a Kermode. Seems people are fascinated with anomalies in wildlife.
Leucism is one reason some wildlife is white. Leucism is a condition in which there is partial loss of pigmentation resulting in white, pale, or patchy coloration of the skin, hair, feathers, scales or cuticle. Leucism does not affect the colour of the eye though and some leucistic birds can have normal coloured legs, feet and beaks. Leucism in birds can weaken their feathers, decrease their ability to warm up in the sun and it can make them more susceptible to predation.
Piebald is a form of leucism which results in wildlife having patches of white mixed in with their normal colouration. The patchy pattern is a result of the loss of pigmentation in just some of the animal’s pigment cells.
Albinism is another reason why some wildlife can be white. Albinism is the congenital absence of one type of pigmentation – melanin. Albinism causes white hair and skin as well as pink or red eyes. Albinism occurs in humans, animals and plants. Survival of albino wildlife can be lower because they lack UV protecting skin and eye pigments which can be a serious issue for some species. Reptiles that can only get their body heat from the sun can have a tougher time making a go of it when their white skin reflects the sun’s rays. Albinos were once thought to be sterile and a result of in breeding, but those myths have been proven to be false.
Canada has its fair share of white-coloured wildlife. In 2017, this video surfaced of a white cow moose and her calf in Ontario. In Canada, fully white and piebald wildlife have been reported in species that are not normally white including moose, elk, deer, turkey and grizzly bears as well as captive bison.
While the white moose in Sweden ended up being taken by a hunter, any moose in Ontario that is more than 50% white cannot legally be taken by a hunter.
The Kermode bear, a white-coloured black bear, is the result of a genetic trait in a sub-population of black bears found only in British Columbia. Kermode or “Spirit Bears” as some people in BC call them, live in a narrow zone of coastal habitat on BC’s mid-coast region. The Kermode is BC’s official mammal and it is on one of the BC Parks conservation vehicle license plates.
The high number of Kermode bears is thought to be unique to the northwest coast of BC because the bears carrying the “Kermode gene” are relatively isolated from black bear populations elsewhere in BC and from black bears in Alaska and the Yukon. The frequency of the Kermode gene is higher in the population of black bears living on an archipelago along the mid-coast of BC than it is in the bear population on the adjacent coastal mainland. As a result, more white Kermode bears are found on the islands than on the mainland.
What’s also interesting about these white bears is that a white Kermode female can have black cubs, or a mix of white and black cubs and a black female can have white cubs or a mix. The white “Kermode gene” is recessive and the black gene is dominant. So, if a bear cub has one white gene from one parent and one black gene from the other parent, it will be black. If the cub has a white gene from each parent its fur is white.
On rare occasions albino black bears have be found in BC. To protect the sub-population of Kermode bears, the hunting of any white black bear in the province is prohibited. Hunting black-coloured black bears is prohibited on the islands where the highest concentration of Kermode bears is known to occur. However, black-coloured black bears living on the adjacent coastal mainland, where the frequency of Kermode gene carrying bears is lower, are not protected from licensed hunting.
Animals with full-time white coats including mountain goats and Dall sheep are white because evolution proved that being white all the time is an advantage to their survival. Given where they live, Dall sheep and mountain goats can be snowed on at any time during the year. Sporting white coats year around is likely concealment from predators. But when there is no snow and the grass is green these white animals sure stand out.
Maybe being more visible at certain times of the year helps Dall sheep and goats find each other in the vastly huge landscapes they inhabit or maybe being white makes keeping track of offspring easier in the early spring easier. There is still a lot of work to be done to figure out how nature works!
The intensity of the sun’s rays at higher altitudes and at more northern latitudes can be damaging to living tissue. The Dall sheep and mountain goat’s white coats may also be important properties for UV protection. Their white hair could also be a way to help these animals stay cool in the summer since they don’t often live near forested habitats nor do they like being in the forest where they can’t see keep a watch out for predators. Whether the advantage of having a white coat is related to camouflage, visibility or UV protection, these animals’ white coats are not caused by any rare pigment condition or recessive gene. They were just meant to be white. There is, however, clearly a correlation between latitude, length of winter, temperature and the colours of wild sheep changing from cold white to cool grey to warm browns and tans as you go from Alaska to Mexico.
Snowshoe hare and ptarmigans turn white in the winter because evolution has also proven that white camouflage is critical for these species that happen to be on the bottom of the food chain. If you strap an ice pack on a brown snowshoe hare during the hot summer the fur underneath turns white in about one week. Cold is the trigger that causes the hare’s fur to turn white. Their extremities feel cold sooner than their body core which explains why the first parts of a hare to turn white are its ears and feet.
According to the Canadian Wildlife Federation, ptarmigans have three seasonal plumages per year, whereas most other birds only have two. These plumages keep the ptarmigans, particularly the females, well-camouflaged during each season of the year. Male rock ptarmigan retains its winter plumage for the spring breeding season and into the summer. Their pure white-and-black plumage and red combs make the males look dapper. In addition to camouflage, this colour combo must also be an evolutionary advantage for the males when they need to attract females.
Canada’s Gyrfalcon sports two sets of plumage each year. In the summer, the falcons are grey with black bars which make them look like a peregrine falcon. In the winter, Gyrfalcons look like a skinny version of a snowy owl with white plumage dotted with black bars. The Gyrfalcon’s white colour variation is called a “morph”.
Polar bears, appear white, but they mostly have hollow air-filled hair that is transparent. Polar bear hair acts like fibre optic tubes because they channel UV light toward the bears skin. Polar bears emit white light which gives them the appearance of being pure white. Technically speaking, polar bears are luminescent – they glow white! Under their fur, polar bears have black skin to help absorb the UV light. Polar bears have white skin, but black bears have white skin. Nature is nuanced!
A few of Canada’s arctic islands and a small portion of Greenland are the only places in the world where the pure white Artic wolf (Canis lupus arctos) is found. The Artic wolf is a sub species of the grey wolf.
A whiteish variant of the grey wolf occurs throughout the wolf’s range in North America but they are not as pure white coloured as the Artic wolf. One study reported that the white colour in wolves in regions with ice and snow has long been suggested to be adaptive, concealing coloration to aid successful survival and predation.
Rounding out a look at Canada’s white wildlife there is also the snow goose whose epic flocks make the Canadian prairie look as though it is snow covered when they all land to feed. Canada’s snowy owls are white year around. Male snowy owls tend to be whiter than the females and the females have more black bars in their plumage which is likely a camouflage advantage in the spring when they are on the nest.
Canada’s beluga whales and massive Trumpeter swans are pure white all season long. The Arctic fox has a summer and winter colour phase. They are pure silky white in the winter and a mix of earthy browns and tans in the summer. The famous ermine changes from brown to pure white in the winter, except for the black tip on its tail.
There are a few fake white wildlife species though. I saw “White Canadian Pheasant” on a menu in Las Vegas once. The waiter assured me it was a real species of wild fowl living in Canada.
Wildlife living on Canada’s wild public lands is a never-ending source of fascination for me. The fact that Canada is home to several unique white wildlife species and, combined with the fact that a few odd balls crop up now and again, highlights the richness of our country’s biodiversity.
For me, the “C” in conservation stands for curiosity. Curiosity is the first part of conservation because it drives me to learn more about what I see in the natural world and learning leads me to appreciate what I see. It is this appreciation that leads me to advocating for the conservation of wild places and wild things.
Cover Photo Credit: Anders Tedeholm/imagebank.sweden.se