Covering nearly 10 million sq km/3.9 million sq mi, Canada is the second largest country in the world in terms of physical size. It is exceeded only by Russia, whose landmass totals some 17 million sq km/6.6 million sq mi. Having shores on three oceans (Atlantic, Pacific and Arctic), Canada occupies most of the northern part of the North American continent. Yet its inhabitants, largely concentrated along the Canadian/US border, number only about 32 million. The country is divided into 10 provinces and three territories.
Spanning six time zones, the country stretches from latitude 41°47’N at Pelee Island in Lake Erie (the same latitude as Rome, Italy) to 83°07’N at Cape Columbia on Ellesmere Island, a mere 800km/500mi from the North Pole. This north-south extension of about 4,600km/2,900mi is countered only by its width. Canada covers more than 5,500km/3,400mi from Cape Spear in Newfoundland (longitude 52°37’W) to the Yukon/Alaska border (141°W). One of the most remarkable features is the immense bite cut out of the coastline by Hudson Bay, named for famed British explorer Henry Hudson. This enormous gulf or inland sea (637,000sq km/245,946sq mi) could be considered part of either the Atlantic Ocean or the Arctic Ocean. In common with the US, Canada shares another noteworthy feature—the Great Lakes, which together form the largest body of fresh water in the world. Finally, the country is characterized by its extremely mountainous western rim
The Great Ice Ages
The physiographic regions described below have been extensively modified in more recent geological times by the advance and retreat of glacial ice. Four times during the past million years, the North American climate has become progressively colder. Snowfall became increasingly heavy in the north and was gradually compressed into ice. This ice began to flow south, reaching as far as the Ohio and Missouri river valleys in the US before retreating. At peak coverage, 97 percent of Canada was submerged under ice up to 3km/2mi deep at the centre and 1.6km/1mi deep at the edges. Only the Cypress Hills and the Klondike region of the Yukon escaped this cover. The last Ice Age receded more than 10,000 years ago.
A sheet of ice of such thickness exerts a great deal of pressure on the earth below. As the ice from each glacial advance retreated, hollows were scoured out of the land and filled with water, and mountain ranges were worn away and sculptured. Today about 2 percent of Canada is covered by glacial ice, mainly in the Arctic islands, but glaciers are found in the western mountains (Columbia Icefield and St. Elias Mountains).
Major Natural Regions
Physiographically, Canada has at its centre a massive upland known as the Canadian Shield, which forms the geological platform for the whole country. This upland is partially surrounded by areas of lowland that in turn are rimmed by mountain ranges on three of Canada’s four sides; to the south the country lies open to the US. Only in parts of the north do these mountain rims flatten out to form a coastal plain. Seven major physiographic regions can be distinguished.
The Canadian Shield
This massive horseshoe-shaped region surrounding Hudson Bay encompasses nearly half of Canada’s area. The terrain is formed of ancient, hard rocks of the Precambrian era (over 500 million years old) known for their great rigidity and strength. This strength and the region’s shape are the origin of the name “Shield.” The region is characterized by its innumerable lakes and rivers (Canada possesses as much as a quarter of the world’s total supply of fresh water, largely concentrated in the Shield), by its rugged nature (a combination of rock and bog that makes much of the area inaccessible) and by its lack of agricultural soil. However, the region is also the source of much of the country’s extensive mineral, forest and hydroelectric wealth.
Great Lakes/ St. Lawrence Lowlands
Despite their comparatively small size, these lowlands, which extend south into one of the great industrial and agricultural belts of the continent, are home to over 50 percent of the country’s inhabitants. They were created in Palaeozoic times (200 million–500 million years ago) when great stretches of the region were flooded by the sea for long periods. During this flooding thousands of feet of sedimentary rock accumulated on top of the Canadian Shield, providing fertile soil that has made the region important for agriculture today. This factor, combined with a favourable climate and proximity to the US, has made these lowlands Canada’s richest and most industrialized area as well as its most populous.
Prairies and Mackenzie Lowlands
The geologic history of these lowlands is similar to those of the Great Lakes/St. Lawrence region. Material eroded from the Shield and the marginal mountains (in particular, the Rockies) was first deposited in shallow seas. Subsequently swept by glaciers, the flat plains in the south consist of fertile soils ideal for wheat and general farming. The Mackenzie Lowlands begin north of a low divide between the Saskatchewan and Athabasca rivers, and support little agriculture because of their northerly latitude. In places where the Mackenzie Plain joins the Shield, a series of large natural basins form great lakes—Winnipeg, Athabasca, Great Slave, Great Bear and others.
Hudson Bay and Arctic Archipelago Lowlands
The northern counterpart of the Great Lakes/St. Lawrence region, these lowlands are widely scattered portions of a partially drowned plain of Palaeozoic rock that once covered the northern part of the Shield. They slope gently away from the Shield with little relief. Owing to its northerly latitude, severe climate and frozen soil, this area supports little except a vegetation of moss, lichens and small hardy shrubs in sheltered areas.
About 200 million years ago, these mountains, which stretch from Alabama in the US to Newfoundland, were the first to be folded on the edges of the continent. Since then, extensive erosion by ice, rivers and sea has reduced them to mere stumps of their former heights. Today the region is a series of generally flat to rounded uplands, with few sharp peaks rising to no more than 1,280m/4,200ft. Prince Edward Island, and the Annapolis, Ristigouche and Saint John River valleys are notable areas of plains where ancient glacial lakes have left fertile soil.
The Canadian Cordillera consists of five major parts (from east to west): the Rocky Mountains, the interior basins and plateaus, the Coast Mountains, the Inside Passage along the coast and, finally, the outer system of islands. Covering the western quarter of the country, this great sweep of mountains is part of North America’s long mountain system known as the Western Cordillera.
The Canadian Cordillera is a relatively recent geological development. About 70 million years ago, enormous earth forces thrust these mountains up with a great deal of faulting, folding and volcanic activity. Since then, erosion and uplifting by glaciers, and partial drowning by sea have produced a deeply indented coast.
These mountains in the extreme north of the country probably rose after the Appalachians. They consist of two fairly distinct parts: the rounded hills of the Parry Islands and the folded peaks of Ellesmere Island.
The flora of Canada consists of roughly 4,200 species, about 30 percent of which have been introduced. The tree line crosses Canada in a rough diagonal from the Mackenzie Delta to Hudson Bay and the Atlantic. The tundra lies north of this line, a land of lichens, sedges and stunted shrubs. Because the growing season is too short to allow vegetation to germinate and produce seed, most flowering plants are small perennials, sprouting large flowers to attract insect pollinators. Farther north, ice and bare rock dominate, yet some hardy species flourish here, growing as dense mats wherever moisture, heat and nutrients create favourable microhabitats.
South of the tree line, the boreal forest of spruce, tamarack and other conifers gradually begins, interspersed with innumerable bogs, marshes and other wetlands. Farther south, broadleaf trees such as birch, aspen and poplar appear, and some wetlands support commercial cranberry and blueberry farms. More deciduous trees are found until mixed forest predominates.
In the east, forestry, agriculture and urbanization have left only isolated pockets of old-growth forest. Hardwoods such as maple, birch and beech compete for well-drained soils with commercial stands of conifers like spruce and pine, while stands of cedar and alder occupy wetter areas. Only in Southern Ontario are the conifers of the north completely left behind and a true deciduous forest exists. The remaining wetlands support cattails, water lilies, sedges and ferns, as well as successful alien species like purple loosestrife, which came from Europe some 200 years ago as seeds in cattle fodder.
In the west, conifers give way to vast groves of aspen and poplar as one travels south from the tree line, until trees almost completely disappear once again, replaced by rolling prairie grasslands. The region is now highly cultivated, producing much of Canada’s grain crops, so that only scattered remnants of the natural grasses remain in their native state. The mountain region of the West also has its own vegetation pattern, the trees thinning out as they approach the alpine tree line in the same way as they do in the North. Along the Pacific Coast, temperate rain forests with the highest biomass per hectare on earth flourish due to a combination of year-round mild temperatures and very heavy rainfall. As clouds move eastward, they deposit most of their moisture on western slopes, leaving pockets of the interior mountain region dry and dominated by sparse grasses, sagebrush and cactus.
Canada’s varied landscape hosts several species of animals typical of regional fauna. Vast forests provide habitat for white-tailed deer, black-tailed deer and mule deer, while wapiti, also known as the American elk, populate mountainous terrain and prairieland. Largest of the deer family is a distinctively Canadian animal, the moose, which inhabits the forests of Newfoundland west to British Columbia, as do woodland caribou, another member of the deer family. Also distinct is the Canada lynx, previously located throughout the country but now surviving in the northern mainland and in Newfoundland. Rare in Canada is the wolverine (of the weasel family), found in sparse populations in the western and northern part of the country. The grizzly bear and particularly the black bear are common denizens of Canada’s coniferous and deciduous forests. Trapped nearly to extinction, beavers once again thrive across Canada, occupying the streams and ponds of forested regions. Once common to forest, prairies and tundra, wolves reside primarily in the northern wilderness.
Populating Arctic coasts and islands are polar bears that feed on Canada’s varied seal population, such as the grey, harp and hooded seals. Over 30 species of whales ply Canada’s coastal waters, including the humpback and fin (off Newfoundland); the orca and the grey (off British Columbia); and the beluga, blue, fin and minke (St. Lawrence estuary). The Arctic tundra supports musk-oxen, lemmings, foxes and wolves as well as barren-ground caribou.
Wildlife of the prairies includes the gopher, jackrabbit and grouse in addition to pronghorns and bison (cattle family), known more commonly in North America as buffalo. Once numbering in the millions, bison were nearly extinct by 1885, hunted for their hides and meat. Wood Buffalo National Park protects a large population today.
Roaming the mountains of western Canada are mountain goats and mountain sheep. Thinhorn or Dall sheep are found along Canada’s Alaska Highway, while bighorn sheep frequent British Columbia’s south-central ranges and the Canadian Rocky Mountains.
Canada’s bird population ranges from waterfowl such as the Canada goose, Atlantic puffin and piping plover to the interior’s peregrine falcon and rare whooping crane. The bald eagle breeds in parts of northern and eastern Canada, but is most commonly seen along the British Columbia coast. Although most species are migratory, over 400 species of birds have been documented as breeding in Canada.
Canada’s climate is as varied and extreme as its geography. In a large area of the country, winter lasts longer than summer, yet the latter, when it comes, can be very hot. In the north, long hours of daylight in the summer cause prolific plant growth. The central provinces of Canada receive the most snow, far more than the Arctic, which in fact receives the least precipitation of any region.
One major factor influencing climate is proximity to large bodies of water: chiefly, the Pacific and Atlantic oceans, Hudson Bay and the Great Lakes. Such expanses tend to make winters warmer and summers cooler. Regions distant to them are inclined, therefore, to have much colder winters and hotter summers. But terrain is also a factor. In the West the high Coast Mountains shield the interior of British Columbia and the Yukon from the mild and moist Pacific air, making their climate more extreme than their location would indicate. The Rockies intensify this trend, leaving the prairies vulnerable to both Arctic winds and hot southern breezes.