Woolly Mammoths - Mammuthus Primigenius
A mammoth is any of a number of an extinct genus of elephant, often with
long curved tusks and, in northern species, a covering of long hair. They
inhabited the northern regions of the world, in Europe, northern Asia, and
North America.
Many types of mammoth lived in temperate and northern climes: the frozen
remains of woolly mammoths have been found in the northern parts of Siberia.
Frozen mammoth corpses, when removed from the ice, often prove remarkably
fresh: dogs accompanying the finders sometimes ate the flesh. There have
been proposals to clone freshly defrosted mammoths in order to revive the
species.
In addition to occasional frozen mammoths, large amounts of mammoth ivory
were found in Siberia, and were an article of trade for many centuries.
It is a common misconception that mammoths were much larger than modern
elephants, an error that has led to "mammoth" being used as a adjective
meaning "very big". The largest known species, the Imperial Mammoth of
California, reached heights of at least 4 meters at the shoulder. However,
most species of mammoth were about as large as a modern Indian elephant, and
fossils of a species of dwarf mammoth have been found on remote islands off
the east coast of Siberia.
The mammoths diverged from the Asian elephants after the latter group split
from the African elephants, meaning that the mammoths were in fact more
closely related to the modern Indian elephant than the African elephant is.
Since there is a known case in which an Indian elephant and an African
elephant have produced a live offspring, it has been theorised that if
mammoths were still alive today, they would be able to interbreed with
Indian elephants, and this has led to the idea that perhaps a mammoth-like
beast could be recreated by taking genetic material from a frozen mammoth
and combining it with that from a modern Indian elephant. However, not
enough genetic material has been found in frozen mammoths for this to be
attempted.
Woolly mammoths are often considered to be symbolic of the last ice age
(Quaternary the last 2 million years) because of their large size, broad
geographic distribution, relative abundance during the last glaciation, and
adaptation to cold environments.
A great deal is known about the appearance of these hairy elephants as a
result of the discovery of several well-preserved carcasses in frozen ground
in Siberia. Other information has come from the study, in European caves, of
many detailed carvings, engravings and murals by Stone Age (Paleolithic)
artists. Woolly mammoths grew to the size of Asiatic elephants (about 3 m
high at the shoulders) and had similar teeth. Their cheek teeth were
massive, comprising a large series of tightly appressed enamel plates filled
with softer dentine, all surrounded by cementum, which anchored the teeth in
the jaw. As these teeth wore, the enamel ridges stood out and were excellent
grinding mills for the relatively tough, dry grasses on which these animals
habitually fed. As in modern elephants, during a complete lifetime six
molar-like teeth developed in each side of each jaw, making 24 teeth in all.
Of the six sets of teeth, never more than two were in use at the same time,
because there was not enough space in the mouth. Successive teeth grew
forward from the back of the jaw replacing earlier, smaller teeth as they
wore, moved forward, and dropped out.
The coats of woolly mammoths were similar to those of muskoxen, consisting
of long, (up to 90 cm), dark guard hairs and fine underwool, underlain by
dark-grey skin and an insulating fat layer, which in some cases was up to 90
mm thick. Evidently woolly mammoths, like muskoxen, moulted in summer.
Other features characteristic of this species were: a high, peaked head that
appears knob-like in many cave pictures, a high hump resulting from the long
spines of the neck vertebrae (possibly accentuated by fat deposits and thick
hair), a trunk (1) shorter than those of the living Asiatic or African
elephants (Elephas maximus or Loxodonta africana), and large (up to 4.2 m),
elaborately curved tusks. The tusks of females are smaller than those of
males. The undersides of the tusks often show wear, suggesting that they
were used in scraping snow and ice off vegetation or were worn against the
ground during feeding. Rarely, while one tusk developed to normal size, the
other remained a mere stub perhaps due to damage in youth or to abnormal
genetic control. Elephant tusks are, in fact, only transformed second upper
incisor teeth.
Woolly mammoths were first recorded in deposits of the second last
glaciation (possibly 150,000 years ago) in Eurasia, and were derived from
steppe mammoths (Mammuthus trogontherii). As time progressed, several
changes occurred in the cheek teeth of woolly mammoths. The series of enamel
plates became more numerous and crowded and the tooth enamel became thinner.
Apparently, at the same time, the tusks became more curved and body size
decreased. Such changes were advantageous in chewing tougher tundra
vegetation, and probably the decrease in body size (accompanied by reduction
of extremities such as the ears and trunk) and development of a thicker pelt
enabled the mammoths to survive under increasingly cold conditions.
Remains (especially the durable molar teeth and tusks) of this species have
been found in the northern parts of Eurasia and North America. Woolly
mammoths probably originated in north-central Eurasia, spreading westward to
England and Spain, and eastward via the Bering Isthmus (2) to the
tundra-like regions of North America.
During the last glaciation, when most of Canada was covered by ice, the
species was isolated in refuges north and south of the ice sheets.
In the northern area, one of the best preserved specimens consists of much
of the front part of the body of a young woolly mammoth from Fairbanks
Creek, Alaska, tentatively radiocarbon dated at about 21,000 years old.
In life this baby, called "Effie", would have weighed about 100 kg. One of
the best Canadian specimens from this area is a skeleton from Whitestone
River, Yukon Territory (Figure 2).
The mammoth died there about 30,000 years ago, according to a radiocarbon
date. In the southern refuge, remains of woolly mammoths have been found in
the southern parts of British Columbia, Alberta, Saskatchewan, Manitoba and
Ontario, in addition to North Dakota, South Dakota, Minnesota, New York,
Virginia and the Atlantic continental shelf off Virginia.
The habitat of the woolly mammoth is clearly indicated by its physical
appearance and eating habits. All evidence points to its adaptation to cold
climate. Generally in North America its remains are reliable indicators of
deposits of the last glaciation (about 90,000 to 10,000 years ago) and
tundra-like conditions: tundra, tundra-boreal forest margin, or cold
loess-steppe (an environment resulting from massive deposits of fine
windblown dust at the edge of ice sheets).
In 1977, the well-preserved carcass of a baby woolly mammoth, subsequently
named "Dima", was recovered from permafrost on a tributary of the Kolyma
River in northeastern Siberia. It was 115 cm long by 104 cm high and, at
death, weighed approximately 100 kg.
Chestnut-coloured hair was preserved, particularly on the lower parts of the
legs. According to radiocarbon dating, the animal died about 40,000 years
ago. "Dima's" internal organs do not differ significantly from those of
living elephants, but its ears are only one-tenth the size of those of an
African elephant of similar age (7 to 8 months).
Scimitar cats (Homotherium serum) and American lions (Panthera leo atrox)
may have preyed on the young, but adults would have been formidable
adversaries. Paleolithic hunters apparently killed woolly mammoths in large
numbers in Eurasia, particularly in Ukraine, where the species was of great
economic importance. In the Old Crow Basin of the Yukon, mammoth limb bones
often show signs of breakage by humans, who probably developed special
methods for making and using tools of mammoth bone. In Alaska, a fluted
point made by an early hunter was found with bones of a young elephant,
probably those of a woolly mammoth.
A great variety of Paleolithic structures, tools and carvings have been made
from mammoth bones and tusks. Examples are: ice age huts (more than 70 were
found across the Russian Plain), needles, awls, harpoons, boomerangs,
cleavers, shaft wrenches, musical instruments, figurines, dolls, bracelets,
beads, pendants and combs.
Woolly mammoths could not cope with the rapidly changing environment and
increasing human predation toward the close of the last glaciation, and most
became extinct about 11,000 years ago. However in 1993 came the startling
announcement that dwarf woolly mammoths radiocarbon dated between 7,000 and
3,700 years ago lived on Wrangel Island. So while the pyramids and
Stonehenge were being built in Egypt and England respectively, dwarf
mammoths roamed the relic mammoth steppe on this small island off the coast
of northeastern Siberia!
- Wikipedia