|The Pleistocene epoch (IPA: ['pla?st??si:n or 'pla?stosi:n]) on the geologic timescale is the period from 1,808,000 to 11,550 years BP (Before Present). The name Pleistocene is derived from the Greek p?e?st?? (pleistos "most") and ?a???? (kainos "new"). The Pleistocene follows the Pliocene epoch and is followed by the Holocene epoch..||the PLEISTOCENE
|The Pleistocene is the third epoch of the
Neogene period or 6th epoch of the Cenozoic
era. The end of the Pleistocene corresponds
with the end of the Paleolithic age used
The Pleistocene is divided into the Early Pleistocene, Middle Pleistocene and Late Pleistocene, and numerous faunal stages.
Wikipedia, the Free Encyclopedia
We express appreciation for information gleaned
from Wikipedia, the Free Encyclopedia
for some of the material from that website, which has been used on this and other geological age pages,
on this website. We also have used material from other sources, which we try to note, and research done by
your Curator. More will be added and changes will be made in time, with more research on this geological age.
For now, to provide some information, we have borrowed heavily on Wikipedia and make such acknowledgment here.
Moving from the Holocene Epoch, i.e. the present geological age in which we now live, back one geological age, we arrive at the Pleistocene Epoch. The Pleistocene Epoch is better known to most people, than many more ancient epochs. Partly because it preceded the present epoch, and partly because we recognize that some of the terrain in our country was caused by the glaciers, of the Ice Age, in the Pleistocene and we can see the evidence of that age in our geography today. Also partly because remains of Ice Age animals are found regularly. Near the end of the last Ice Age, was the extinction in North America of many animals, of which we have seen artist's renditions of what they looked like. Fortunately, paleontologists and others also have been able to recover the actual frozen remains of some of these Ice Age animals, in places like Siberia in Russia and in Canada and other places to the far north, including within the Arctic circle.
At the end of the Pleistocene Epoch, many of the Ice Age animals became extinct near the close of that Epoch. This included such things as the Probicids (elephants such as Columbian Mammoths, Woolly Mammoths), Mastodons (which were not elephants), and other animals like the Woolly Rhinoceros, Saber Tooth Tiger, Dire Wolf, Irish Elk, Cave Bear, Cave Lion, Giant Hyena, and many others. However, some Ice Age animals did survive, such as Muskox, Polar Bears, Seals, Walruses, Whales, and many others.
Let us look at some of the Ice Age animals,
starting with those which lived during
and/or evolved during the Ice Age, and survived to the Holocene Epoch.
POLAR BEAR (Ursus maritimus)
Only recently in evolutionary time have bears adapted to life on arctic seas, but these great creatures have mastered the water and ice environment superbly. Over time they evolved a luxuriant white coat and layer of blubber for camouflage and warmth. Oversize feet serve as paddles for extensive swimming and spread their weight, helping this largest of modern carnivores (excepting Orcas) to traverse ice too thin to support a person.
During the Ice Age, seals adapted to life in icy northern seas. Their need to breathe and reproduce at the surface put a rich year-around food resource within reach of a population of brown bears that began to live more and more out on the ice. Natural selection favored those bears best able to catch seals, and they became more thoroughly carnivorous than other bears. By 100,000 years ago they had evolved into something like the polar bear of today. Although polar and brown bears now look and act rather differently, their genetic closeness is demonstrated by matings in zoos that produce fertile offspring.
Polar bears' range is circumpolar. A few
have been spotted close to the pole, but
heavy perennial ice there provides poor seal
hunting, so most are found further south
where the ice is thinner and less continuous.
Formerly it was believed that polar bears migrated freely all across the Arctic, but modern research suggests that there are actually a number of more or less distinct populations. Russian and American are investigating the possibility that Beringian bears comprise a single group which during winter is distributed from Wrangel Island south along the Asian coast and in the central Bering Sea as far as St. Mathew Island. In summer, those wintering in the Bering Sea return to the north with the retreat of pack ice. Beringian bears seldom mingle with another population found in the Beaufort Sea east of Pt. Barrow, Alaska.
In 1981 the IUCN Polar Bear Specialist Group agreed that the world population was between 20,000 and 40,000. As of 1988 the most accepted estimate for the Alaska populations was 3,000-5,000.
Ringed seals are the bears' principal prey.
They also hunt bearded seals and occasionally
the more dangerous walrus. Normally solitary
hunters, they have an impressive range of
strategies, learn quickly, and show immense
patience, power and speed. It has been calculated
that their caloric needs require one ringed
seal every six and a half days. Arctic foxes
live on the sea ice in winter by scavenging
polar bear kills.
Since their prey is available year-round, polar bears do not hibernate like brown bears, except pregnant females, who spend about five months in dens to give birth to their cubs. The female must greatly increase her weight, mostly in fat, to carry off a successful pregnancy and denning. The cubs, usually two, are born in December or January, weighing only 0.5 to 0.9 kilograms (one to one and a half pounds). By the time the family breaks out of the den in March or April the cubs weigh 10-15 kilograms (25-30 pounds). Cubs generally remain with their mother for two and a half years. Females are therefore able to bear young only every three years. This low rate of reproduction is balanced by a long life and low rates of natural mortality.
Moving in autumn from drifting ice to suitable denning sites requires a remarkable and little understood navigational ability. An important denning area for the Beringia population is on Wrangel Island. Denning also occurs on the northeastern coast of Alaska, although a majority of the Beaufort population dens on sea ice.
About 4,000 years ago the ancestors of present
day Eskimos moved into an ecological niche
not yet occupied by people: hunting marine
mammals of the northern seas. Once they learned
this life-style they spread quickly along
Arctic coasts. They had discovered much the
same niche as the polar bear and may even
have learned from bears, for their seal hunting
methods are strikingly similar.
Polar bears have a preeminent place in Eskimo cultural and spiritual life. The spiritual guardians of shamans were usually polar bears, and it was believed that the spirits of people and bears sometimes interchanged. Killing a bear was a major event, requiring ceremonial propitiation of its spirit. Sometimes it was the bear who killed the person, for the predator-prey relationship went both ways.
The above information on Polar Bears is from the webpage on Polar Bears of the Bering Land Bridge National Preserve, which webpage is http://www.nps.gov/archive/bela/html/polar.htm. Our appreciation for this information.
MUSKOX (Ovibos moschatus)
The Muskox (Ovibos moschatus) is an arctic mammal of the Bovidae family, noted for its thick coat and for the male's strong odor, hence the name.
It belongs to the Caprinae subfamily, being
more closely related to goats than to oxen,
but is in its own genus, Ovibos. Both sexes
have long curved horns. Muskoxen are usually
around 2.5 m (8.2 ft) long and 1.4 m (4.6)
high at the shoulder. Adults usually weigh
at least 200 kg (440 lb) and can exceed 400
kg (880 lb). Their coat, a mix of black,
gray, and brown, includes long guard hairs
that reach almost to the ground.
During the summer, Muskoxen live in wet areas, such as river valleys, moving to higher elevations in the winter to avoid deep snow. They graze on grasses, reeds, sedges, and other ground plants, digging through snow in the winter to reach their food.
Muskoxen are social and live in herds, usually of around 10–20 animals, but sometimes over 400. Winter herds consist of adults of both sexes as well as young animals. During the mating season, which peaks in mid-August, males compete for dominance, and one dominant bull drives other adult males out of the group. Non-breeding males will often form male only herds of 3-10 or wander the tundra alone. During this period all males are extremely aggressive. Bulls will even charge birds if they are close by.
The last known Muskox from outside North America, that lived on the Taymyr Peninsula of Siberia, died out about 2,000 years ago. Muskoxen are native to the Arctic areas of Canada, Greenland, and Alaska. The Alaska population was wiped out in the late nineteenth or early twentieth century, but Muskoxen have since been reintroduced to Alaska. The species has also been reintroduced from Banks Island to northern Europe, including Sweden, the Dovre region of Norway, and Russia and from Ellesmere island to Eastern Canada, in the province of Quebec. Muskoxen were close to extinction at one point, but have recovered after being protected from hunting. The world population (as of 1999) is estimated at between 65,000 and 85,000, with two thirds living on Banks Island. It is increasing, especially in the areas where the animal was introduced in the 20th century. All of the above information on Muskoxen is from Wikipedia with a link http://en.wikipedia.org/wiki/Musk_ox.
One reason that Muskoxen purportedly came close to extinction is that the defensive mechanism of the large males, upon danger, would form a line facing outward, shoulder to shoulder making a living fence. However, it also made for a steady unmoving line for firearm use to mow down a line of Muskoxen.
The history of musk ox dates back to thousands of years. Already before the last ice age musk oxen roamed the Arctic Tundra with mammoths, rhinoceros, and Greenland caribous. One can assume musk ox roaming in Northern Europe, possibly even in the regions of Ranua, at least 40 000 years ago. Musk ox survived ice age in Greenland and on the Arctic Islands of Canada. Nowadays these animals are to be found amongst others in Northern Canada, where about 80 % of all 100 000 musk ox species in the whole world are living. In Greenland the estimated amount of musk ox is 20 000. Musk ox has been transplanted, amongst others, in Alaska, in the Spitzbergen and Russia. The wild musk oxen, living closest to us, are to be found in Norway in the regions of Dovrefjäll, where they were transplanted from Greenland in the fifties. Some of these musk ox species, nowadays to be found in a herd of less than 10, have moved to Sweden in the regions of Härjedalen. This paragraph from the Wildlife park Ranua-Lapland's website at http://www.ranuawildlife.fi/?deptid=18227.
SABER-TOOTHED CAT (X)
GIANT GROUND SLOTH (X)
WOOLLY RHINOCEROS (X)
CAVE LION (X)