Quaternary Vertebrate Fossils

Quaternary Vertebrate Fossils

  The most productive ICE AGE (Quaternary - the last 2 million years) faunas occur around the margins of the relatively barren, formerly heavily-glaciated Precambrian SHIELD. In variety of species represented, quantity of FOSSILS and sequences of fossil-bearing deposits of different ages, perhaps the most significant sites are in the Yukon (Mountainous zone) and the Prairies (Flat sedimentary zone). The richest known sites in Canada are in the Old Crow and Dawson City areas of the Yukon. Since Canada is bound by three oceans, Quaternary marine mammal faunas (Coastal zone) are important, and some of the most significant ones conclude this summary.

Mountainous zone
The unglaciated areas of the Yukon Territory within the Cordilleran part of the mountainous zone contain the most productive Pleistocene (about 2 million to 10 000 years ago) VERTEBRATE fossil localities in Canada. Nearly three-quarters of the Yukon Pleistocene mammals came from Eurasia, the remainder reaching the Yukon from southern North America. The vertebrate fossils include a wide variety of species (about 7 species of fishes, 1 amphibian, 40 of birds and 70 of mammals). They extend from the earliest known fauna at Fort Selkirk (about 1.6 million years old) to the Old Crow Loc. 11(1) fauna (nearly 12 000 years old), by which time most of the larger ice age mammals (eg, woolly mammoths, American mastodons, HORSES and steppe BISON) had become extinct in the Yukon. Although the cause of this extinction is not known, perhaps it can be attributed to rapid climatic changes near the close of the Pleistocene, exacerbated by human hunting. Indeed the Yukon holds important evidence of the earliest-known people in North America (e.g. artifacts made from mammoth, caribou and bison bones from Bluefish Caves, Old Crow and Dawson City areas).

The OLD CROW BASIN is the richest area for ice age vertebrate remains in Canada, having yielded more than 50 000 specimens representing nearly 60 mammal species. The bones are mainly exposed through natural erosion of the winding Old Crow River. They range in age from about 1.4 million years ago to about 12 000 years ago. Approximately 150 fossil localities are known within the Basin. Old Crow Loc. 94 is nearly 1.4 million years old and represents an Early Pleistocene interglacial. This fauna contains giant pika, several primitive rodents, mammoth and horse. Old Crow Loc. 47 is more than 180 000 years old and includes fish, bird, SHREW, "rabbit", giant BEAVER and other rodents, "weasel", WOLF, FOX, steppe mammoth, horse, CARIBOU and bison. The Old Crow Loc. 44 fauna of last interglacial age (about 130 000 years ago) contains remains of 7 fish, 7 bird and 31 mammalian species. Many of these (e.g. fish, DUCK, GOOSE, shorebird, beaver, giant beaver, MUSKRAT) are aquatic, and suggest the presence of shallow ponds and lakes in a river floodplain, with spruce-larch forest nearby.

 BLUEFISH CAVES (I-III) is one of the most important cave sites in Canada because it contains: (1) evidence of some of the earliest people in North America (from about 25 000 to 10 000 years ago); (2) a well-marked transition between Pleistocene and Holocene (10 000 years ago to the present) sediments, flora and fauna; and (3) a substantial variety of fossils of both large and small mammals adapted to northern conditions, as well as those of migratory birds. A significant specimen from Cave II is a mammoth limb bone flake (a fragment removed by human percussion or pressure) and its parent core dating to 23 500 years ago. Further, a split caribou tibia like a broken human-made fleshing tool has been dated to 24 800 years ago. The Pleistocene vertebrate fauna includes: 2 fish species, at least 23 bird species, many smaller mammals including 9 species of rodents, wolf, brown BEAR, steppe ferret, COUGAR, American lion, mammoth, Yukon horse, WAPITI, MOOSE, caribou, saiga ANTELOPE, steppe bison, tundra MUSKOX, and Dall SHEEP. This fauna evidently lived in a grassy steppe-tundra environment drained by the proto-Bluefish River during the cold, dry conditions of the Last Glacial Maximum (about 18 000 years ago).

Ice age vertebrate remains near Dawson City are mainly exposed during placer mining for gold. Nearly 70 fossil localities are recorded in the region. Most of the bones are Late Wisconsinan (about 30 000 to 15 000 years ago) in age. One of the most spectacular specimens from the area is a partial Yukon horse carcass from Last Chance Creek that dates to about 26 000 years ago. Other remarkable specimens are most of a left forefoot of a steppe bison covered with dried muscle, skin and chestnut brown hair from Nugget Gulch; and a mummified, hairless lower hindfoot of an immature steppe bison from Dawson Loc. 10 dated to 20 370 years ago. Nearly 90 % of the finds from Dawson Loc. 10 include: steppe bison (46%), Yukon horse (19 %), mammoth (11 %), Dall sheep (11 %) and caribou (3 %). At Nugget Gulch, a volcanic ash layer covered an original grassy surface on which lay indirect human evidence in the form of a steppe bison forelimb bone evidently broken to expose the edible marrow, and excellent specimens of wolf, Yukon horse, and Dall sheep dating to about 30000 years ago. One of the oldest sites is at Midnight Dome, overlooking Dawson City, where fine sands underlying a volcanic ash layer at least 1.5 million years old has produced Early Pleistocene remains of VOLES and LEMMINGS.

At Thistle Creek, southwest of Dawson City, three layers of sediment have produced mammalian fossils. The Middle Pleistocene interglacial beds (about 740 000 years old) contain 14 taxa including a shrew, the first Beringian (BERINGIA was an unglaciated landmass extending from Siberia to the Yukon and adjacent parts of the Northwest Territories) record of a giant PIKA, and a CHIPMUNK; two new rodent species, two kinds of lemming, mammoth, and small horse. Last interglacial and Middle Wisconsinan layers contain remains of ground SQUIRREL, collared lemming, tundra vole, chestnut-cheeked vole, white-footed mouse, horse and caribou.

 At Sixtymile, gold placer sites near the Alaskan border, west of Dawson City, yielded hundreds of excellent Middle Wisconsinan (about 50 000 to 25 000 years ago) specimens. They include remains of GRIZZLY BEAR, woolly mammoth, Yukon horse, the rare western camel, caribou, steppe bison, helmeted muskox, tundra muskox, and Dall sheep. However, the most remarkable specimens are nearly complete carcasses of a black-footed ferret (now barely surviving in northern United States) and an arctic ground squirrel that gave radiocarbon ages of about 39 500 and 47 500 years, respectively.

At Fort Selkirk, near the junction of Yukon and Pelly rivers, geologist Lionel Jackson and his team found many specimens of the most primitive vole, as well as shrew, BAT, pika, HARE, ground squirrel, primitive collared, brown and bog lemmings, WEASEL and caribou. It represents a full-glacial assemblage, and seems to be slightly younger (1.6 million years old) than the earliest-known Eastern Beringian (unglaciated areas of Alaska, Yukon and adjacent Northwest Territories) Pleistocene fauna (about 1.8 million years old) from Cape Deceit, Alaska. Indeed, caribou probably evolved in Eastern Beringia.

Also within the Cordilleran part of the mountainous zone, two British Columbia cave faunas are worth considering. Charlie Lake Cave near Fort St. John is of interest mainly because of its Lateglacial (about 10 500 to 9000 years ago) fossils. The site was visited occasionally by people who left stone artifacts and bones. It was also visited by predators carrying their prey, and by various animals that lived there. The commonest vertebrate remains from the site represent SUCKERS and other unidentified fishes; FROGS; birds, including most commonly Horned GREBE, GROUSE and PTARMIGAN, American COOT, Short-eared OWL and Cliff SWALLOW; and mammals, the commonest being snowshoe hare, ground squirrel and smaller rodents like the collared lemming, as well as bison. These fossils indicate that during this period the landscape was open with some water, marshes and patches of forest - changing to forest about 10 000 years ago. By 9000 years ago, the fauna was modern.

Of several caves on Vancouver Island that have yielded vertebrate remains, perhaps Port Eliza Cave, a raised sea cave near the northwestern coast, is most interesting. A diverse fish, amphibian, bird and mammal fauna (about 3600 specimens) was recorded from basal silty-sandy sediments. The fauna, yielding ages of 18 000 to 16 000 years ago, includes: SALMON, cutthroat TROUT, threespine STICKLEBACK, greenling, pollock, FLATFISH, Irish lord, SCULPIN, tomcod (seeCOD), western TOAD, LOON, small seabird (alcid), CORMORANT, duck, Horned LARK, Savanna SPARROW, Townsend's vole, long-tailed vole, heather vole, MARMOT, American MARTEN, noble marten, as well as mountain sheep. Fishes suggest that the seashore was close enough for predators to have brought this material to the cave. The land fauna indicates a cool, open environment with maximum summer temperatures cooler than present. People could have survived here on a mixed marine-terrestrial diet, demonstrating the possibility of southward human migration along the Pacific coast during the Last Glacial Maximum.

In Alberta, faunal remains from January and Eagle caves are best known. January Cave, located on Plateau Mountain in the Front Range of the Rocky Mountains, some 100 km southeast of Calgary, has yielded remains of: arctic GRAYLING, shrew, pika, hare, hoary marmot, Columbian ground squirrel, woodrat, POCKET GOPHER, long-tailed vole, DEER MOUSE, several small carnivores and bighorn sheep. Roughly 90% of all identified fossils were rodents - probably most were derived from raptor pellets and carnivore droppings. The fauna represents a cool, dry Middle Wisconsinan interstadial (33 000 to 23 000 years ago). Eagle Cave is situated in Crowsnest Pass about 10 km west of Coleman. Like January Cave, the fossil-bearing sediments were deposited during the Middle Wisconsinan (more than 33 000 to 23000 years ago). Pocket gopher and water vole are perhaps the most interesting specimens in the fauna. The water vole represents the oldest known fossil of the species, and its presence in southwestern Alberta suggests equable climate during the Middle Wisconsinan.

In the Appalachian part of the mountainous zone, preliminary collections of undated vertebrate remains from sediments in caves near La Rédemption (Trou Otis and Spéos de la Fée), Québec, have yielded seven mammalian species: eastern long-eared bat, Ungava lemming, American PORCUPINE, red fox, grizzly bear, moose and caribou. The lemming and grizzly bear are of great interest because they are rare in the faunal record of eastern North America. Perhaps they occupied Gaspésie when patches of tundra-like habitat existed there in the Early Holocene (about 10 000 to 5000 years ago).

Flat sedimentary zone

Many important ice age vertebrate sites in Canada lie within the flat sedimentary zone. At Medicine Hat in southern Alberta, a thick sequence of glacial and interglacial (as warm as, or warmer than, the present interglacial) deposits, containing nine faunas ranging in age from Middle Pleistocene (about 1 million years ago) to present, are exposed in bluffs along the South Saskatchewan River. Significant is the earliest record of ground sloth in Canada, perhaps indicating shrubs and trees in what is now a prairie environment. Primitive wolves also appear in this fauna. However, following that period a basically similar dry-grassland fauna evidently prevailed in this region.

A Middle Wisconsinan (about 43 000 to 20 000 years ago) fauna based on a collection of over 10 000 bones from 10 Edmonton area gravel pits include: ground sloth, wolf, short-faced bear, American lion, American mastodon, woolly mammoth, horse, western camel, wapiti, caribou, bison, and tundra muskox. Analysis of more than 30 radiocarbon-dated specimens from across Alberta shows a chronological gap between 20 000 and 11 000 years ago. Evidently, before that period the province was a steppe-like landscape followed by about 10000 years of ice coverage. Archaeological data suggest that people did not enter the area (Vermilion Lakes site, Banff National Park) for another thousand years. However, the human evidence from Bluefish Caves and Dawson, Yukon, indicates that people were positioned to enter the heart of the continent about 30 000 years ago.

Wally's Beach near Cardston, Alberta, is a Late Pleistocene (about 11 000 years ago) archaeological/paleontological site including: birds, human-modified tools and bones, as well as remains of RABBIT or hare, several rodents, canids, BADGER, horse, camel, caribou, ancient bison, and helmeted muskox. Analysis of blood traces on stone tools indicates that CLOVIS hunters killed horses there. Remarkably, many tracks preserved at the site are of woolly mammoth, horse, ancient bison, western camel and caribou, often preserving information on the behaviour of these species.

Wellsch Valley, north of Swift Current, Saskatchewan, has yielded the best evidence of an Early Pleistocene (about 1.7 million years ago) fauna. It consists of several rodents, an extinct bone-eating dog, a primitive mammoth (perhaps one of the earliest in North America) and muskox.

Other Saskatchewan faunas worth mentioning are Saskatoon and Fort Qu'Appelle - both probably of last interglacial age (about 130 000 years ago). The former includes: hare, about eight rodent species including muskrat, COYOTE, fox, horse, extinct camel, llama, deer, PRONGHORN, giant bison and helmeted muskox. The latter consists only of larger mammals: badger (a good grassland indicator), Columbian mammoth, horse, western camel, Scott's moose (probably adapted to parklands), giant bison and helmeted muskox. Five of these species are reported from the Saskatoon site.

Except for a Late Pleistocene (about 40 000 years ago) fauna (which includes woolly mammoth, bison and tundra muskox) from Grunthal Quarry southeast of Winnipeg, Manitoba is not known for its ice age faunas. The Grunthal fauna indicates that the mammoth fauna represented at Edmonton had spread at least as far east as Manitoba during the Middle Wisconsinan.

Farther east at Toronto, Ontario, remains of PIKE, CATFISH, groundhog, giant beaver, large bear, giant moose and another species of deer, and bison have come from the Don Formation of last interglacial age. Basal parts of the Don Formation contain pollen of plants that would have flourished in temperatures nearly 3C warmer than present.

Another last interglacial site near Innerkip, Ontario, has yielded remains of Blanding's turtle, muskrat, vole, and white-tailed deer. The site had a locally rich and varied flora and fauna that probably developed in or near a well-vegetated pond. Studies of insects preserved in the sediments suggest temperatures like those found in southern Ontario today.

Coastal zone

  Canada is bounded by three oceans, Atlantic, Arctic and Pacific, a fact that is obvious when Quaternary marine mammal remains are considered. A few Quaternary vertebrate localities or areas in what is now (or was once) the Atlantic coastal zone deserves mention. Remains from CHAMPLAIN SEA (a western arm of the Atlantic Ocean which covered the Saint Lawrence Lowlands of Québec and Ontario between about 12 000 and 9400 years ago) deposits include five species of WHALES (about 80% represent white whales while others are of harbour PORPOISE, humpback, common finback and bowhead whales). SEALS, especially those adapted to breeding on land-fast ice, such as the ringed seal, and those adapted to breeding on pack ice, such as harp and bearded seal also occupied this sea. Harbour seal and WALRUS have also been recovered from Champlain Sea deposits. At Saint-Nicolas, Québec, tidal current sands of Lateglacial (about 10 000 to 9800 years ago) age preserve an exceptional marine fossil fauna including: fish (STURGEON, Atlantic wrymouth, eelpout, capelin and a salmonid); SEABIRDS (Oldsquaw, Thick-billed MURRE and a larger bird); and marine mammals (ringed seal, walrus and white whale).

More than 400 radiocarbon dates on bowhead whale remains collected from ancient raised beaches help to reconstruct the history of sea ice in the Canadian Arctic Islands over the past 10 000 years. From 10 000 to 8500 years ago, a large bowhead population extended in summer from the Beaufort Sea to Baffin Bay. From 8500 to 5000 years ago, bowheads were excluded from most of the Canadian Arctic Islands because most of the channels failed to clear of sea ice; summer conditions for most of this time were colder than during historical times. From 5000 to 3000 years ago, bowheads reoccupied the central channels of the Canadian Arctic Islands, and their range extended beyond historical limits, suggesting warmer summers than now. From 3000 years ago to the present, sea ice excluded whales from the central channels, as it does today, indicating cooling. The pattern of walrus remains found on raised beaches in the Canadian Arctic Islands reinforces paleoclimatic inferences from the bowhead fossils. The currently fashionable view of global warming may thus be seen in better perspective.

In the Pacific coastal zone a Late Pleistocene (about 12 500 years old) vertebrate fauna was found at the Lerwick Road site near Courtenay, British Columbia, with a partial skeleton of a Steller SEA LION pup - the most complete fossil of this species from Canada. Other Steller sea lion fossils from Bowen Island and Vancouver show that this species occupied both coasts of the Strait of Georgia some 13 000 to 12 000 years ago. Fish remains (mainly Pacific cod and walleye pollock with some salmon) from the site probably reflect selection of prey by adult sea lions at a Late Wisconsinan rookery. White-Fronted Goose was also identified from the site. Associated MOLLUSK remains indicate that marine climate of the fossil locality was considerably colder than now.

See alsoPALEONTOLOGY.