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Saturday, October 25, 2014

All about extinct Woolly - Wiki

The woolly mammoth was one of the last in a line of mammoth species, beginning with Mammuthus subplanifrons in the early Pliocene. M. primigenius diverged from the steppe mammoth, M. trogontherii, about 200,000 years ago in eastern Asia. The closest extant relative of the species is the Asian elephant. The studies on these species were done extensively with the discovery of frozen carcasses in Siberia and Alaska. The woolly mammoth appeared to extinct soon after the evolution of modern man. There are depiction of these creatures in the prehistoric cave paintings. In 1796 Georges Cuvier identified the giant creature as extinct species.
The woolly mammoth was larger than its closest relative Asian elephant. It is almost the same size that as of a modern African elephants. Male has a height ranging from 9 to 11 feet and weighed around 6 tonnes. The female mammoths height varied from 9 to 10 feet and weighed nearly 4 tonnes. A newborn mammoth calf can weigh up to 90 kilograms.
The woolly mammoth was very well adapted to the last ice age since it is covered in long furs. The behavior of mammoths were similar to modern elephants. They use the tusk and trunk to manipulate objects. They had a vegetarian diet with grass and leaves. The life span of of these species are estimated to be 60 years.
Wooly mammoths near the Somme River, AMNH mural.
Wooly mammoths near the Somme River, AMNH mural.
Source: wikimedia
A mammoth tusk with carvings of scenes on the Yukon River, 19th century, Yukon, Alaska. On display at the De Young Museum in San Francisco.
A mammoth tusk with carvings of scenes on the Yukon River, 19th century, Yukon, Alaska. On display at the De Young Museum in San Francisco.
Source: wikimedia
The woolly mammoth coexisted with early modern humans. The species was also hunted for food by man during early days. It disappeared from its mainland range at the end of the Pleistocene 10,000 years ago, most likely through a combination of climate change, consequent disappearance of its habitat, and hunting by humans, though the significance of these factors is disputed. Isolated populations survived on Wrangel Island until 4,000 years ago, and on St. Paul Island until 6,400 years ago. After its extinction, humans continued using its ivory as a raw material, and this tradition continues today. Some are in the opinion the same species can be recreated through cloning. The possibility is not yet feasible as the remaining genetic material is degraded.
In the year 1738, Johann Philipp Breyne suggested that mammoth fossils represented some kind of elephant. He was unable to prove why their fossils were found in coldest part of the continents such as Siberia. He postulated they could have carried away by the Great Flood. In 1796, Georges Cuvier was the first anatomist to identify the woolly mammoth are not remains of modern elephants which were carried away to Arctic by flood, instead it is an entirely new species which was extinct. He is the first person to postulate the species had gone extinct and no longer existed. But Cuvier's theory was not generally accepted during his time.
Following Cuvier's identification, Johann Friedrich Blumenbach gave the woolly mammoth its scientific name, Elephas primigenius, in 1799, placing it in the same genus as the Asian elephant. The meaning of the name is "the firstborn elephant". In a turnaround in 1828 Joshua Brookes recognised the species was distinct enough to warrant a new genus, and reclassified it as Mammuthus primigenius. Still the origin of the word mammoth is not clear.

Evolution of Mammoths

The earliest known proboscideans, the clade which contains elephants, existed about 55 million years ago around the Tethys Sea. The closest known relatives of the Proboscidea are the sirenians and the hyraxes. The family Elephantidae existed six million years ago in Africa and includes the modern elephants and the mammoths. Among many now extinct clades, the mastodon is only a distant relative of the mammoths, and part of the separate Mammutidae family, which diverged 25 million years before the mammoths evolved. Based on hyoid characteristics asian elephants are the closest descendant of woolly mammoths.
The chromosomal DNA of woolly mammoth was mapped. During the analysis of the same, it showed that it is 98.55% to 99.4% identical to African elephants.

Humans and mammoths

Even today the relationship between the woolly mammoth and ice age humans are widely debated. Some say both humans and mammoths coexisted but there is no clear evidence for this theory. Mammoths are the third most widely painted animal in ice age cave paintings after horses and bisons.
Several mammoths fossils suggest that they were hunted down by the humans by the cuts and marks of stone weapons. It is also debated humans scavenged on the mammoths rather than hunting them. A Siberian specimen with a spearhead embedded in its shoulder blade shows that a spear had been thrown at it with great force.

Extinction

Most woolly mammoth populations disappeared during the late Pleistocene and early Holocene, alongside most of the Pleistocene megafauna, during the Quaternary extinction event. Scientists still debate over how mammoths got extinct. Some are in the opinion it is due to climate change, some postulates it is due to hunting. There is also another theory which states, due to shrinkage in habitat space mammoths extincted. Habitat of mammoths shrink drastically towards its extinction period and the remaining population was hunted down by humans. A study in 2010 suggest that since the extinction of the mammoths the temperature of the northern hemisphere could have slightly increased approximately to .2 degree Celsius. This is because the primary diet of mammoths were birch forests. Birch forest can absorb more sunlight than that of grasslands. Since the mammoths extinct, there is an increase in birch forest area resulting in regional warming.