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A mammoth is any species of the extinct genus Mammuthus. These proboscideans are members of Elephantidae, the family of elephants and mammoths, and close relatives of modern elephants. They were often equipped with long curved tusks and, in northern species, a covering of long hair. They lived from the Pliocene epoch from around 4.8 million to 4,500 years ago. The word mammoth comes from the Russian mamont, probably in turn from the Vogul language.

Size



Like their modern relative the elephant, mammoths were quite large; in English the noun "mammoth" has become an adjective meaning "huge" or "massive". The largest known species, Songhua River Mammoth (Mammuthus sungari) , reached heights of at least 5 meters (16 feet) at the shoulder. Mammoths would probably normally weigh in the region of 6 to 8 tonnes, but exceptionally large males may have exceeded 12 tonnes. An long mammoth tusk was discovered north of Lincoln, Illinoismarker in 2005. However, most species of mammoth were only about as large as a modern Asian Elephant. Fossils of species of dwarf mammoth have been found on the Californian Channel Island (Mammuthus exilis) and the Mediterranean island of Sardinia (Mammuthus lamarmorae). There was also a race of dwarf woolly mammoths on Wrangel Islandmarker, north of Siberia, within the Arctic Circle.

Based on studies of their close relatives the modern elephants, mammoths probably had a gestation period of 22 months, resulting in a single calf being born. Their social structure was probably the same as that of African and Asian elephants, with females living in herds headed by a matriarch, whilst bulls lived solitary lives or formed loose groups after sexual maturity.

Well preserved specimens

In May 2007, the carcass of a one-month-old female woolly mammoth calf was discovered in a layer of permafrost near the Yuribei River in Russia, where it had been buried for 37,000 years. Alexei Tikhonov, the Russian Academy of Science's Zoological Institute's deputy director, has dismissed the prospect of cloning the animal, as the whole cells required for cloning would have burst under the freezing conditions. Nonetheless, DNA is expected to be well enough preserved to be useful for research on mammoth phylogeny and perhaps physiology. However, Dr Sayaka Wakayama from the RIKEN Center for Developmental Biology in Kobe, Japan, believes that a technique she has used to clone mice from specimens frozen for sixteen years could be used successfully on recovered mammoth tissue: she argues that in her experiments the dead mice had been frozen to -20°C under simulated natural conditions, without using the usual preservative chemicals.

Researchers at Penn State Universitymarker have sequenced about 85% of the gene map of the woolly mammoth, using DNA taken from hair samples collected from a selection of specimens, advancing the possibility of bringing the woolly mammoth back to life by inserting mammoth DNA sequences into the genome of the modern-day elephant. Although the samples were washed with bleach to remove possible contamination from bacteria or fungi, some DNA bases identified may be from the contaminating organisms and these have yet to be distinguished, by comparison with the genome of the African elephant currently being generated by scientists at the Broad Institute. The information cannot be used to synthesize the mammoth DNA, but Dr Stephan Schuster, leader of the project, notes that the mammoth’s genes differ at only some 400,000 sites from the genome of the African elephant and it would be possible (though not with presently available technology) to modify an elephant cell at these sites to make it resemble one bearing a mammoth's genome, and implant it into a surrogate elephant mother.

Extinction



The woolly mammoth was the last species of the genus. Most populations of the woolly mammoth in North America and Eurasia, as well all the Columbian mammoths in North America, died out around the time of the last glacial retreat, as part of a mass extinction of megafauna in northern Eurasia and the Americas. Until recently, it was generally assumed that the last woolly mammoths vanished from Europe and southern Siberia about 10,000 BC, but new findings show that some were still present there about 8,000 BC. Only slightly later, the woolly mammoths also disappeared from continental northern Siberia. A small population survived on St. Paul Island, Alaska, up until 3,750 BC, and the small mammoths of Wrangel Islandmarker survived until 1,650 BC.

A definitive explanation for their mass extinction is yet to be agreed upon. The warming trend that occurred 12,000 years ago, accompanied by a glacial retreat and rising sea levels, has been suggested as a contributing factor. Forests replaced open woodlands and grasslands across the continent. The available habitat may have been reduced for some megafaunal species, such as the mammoth. However, such climate changes were nothing new; numerous very similar warming episodes had occurred previously within the ice age of the last several million years without producing comparable megafaunal extinctions, so climate alone is unlikely to have played a decisive role. The spread of advanced human hunters through northern Eurasia and the Americas around the time of the extinctions was a new development, and thus probably contributed significantly.

Whether the general mammoth population died out for climatic reasons or due to overhunting by humans is controversial. Another theory suggests that mammoths may have fallen victim to an infectious disease. A combination of climate change and hunting by humans has been suggested as the most likely explanation for their extinction.

Data derived from studies done on living elephants suggests human hunting was likely a strong contributing factor in the mammoth's final extinction . Homo erectus is known to have consumed mammoth meat as early as 1.8 million years ago. (2006): Clashing with Titans. BioScience 56(4): 292-298. DOI:10.1641/0006-3568(2006)56[292:CWT]2.0.CO;2 PDF fulltext

However, the American Institute of Biological Sciences also notes that bones of dead elephants, left on the ground and subsequently trampled by other elephants, tend to bear marks resembling butchery marks, which have previously been misinterpreted as such by archaeologists .

The survival of the dwarf mammoths on Russia'smarker Wrangel Islandmarker was due to the island's very remote location and lack of inhabitants in the early Holocene period . The European discovery of the island (by American whalers) did not occur until the 1820s . A similar dwarfing occurred with the Pygmy Mammoth on the outer Channel Islands of Californiamarker, but at an earlier period. Those animals were very likely killed by early Paleo-Native Americans, and habitat loss caused by a rising sea level that split Santa Rosae into the outer Channel Islands .

See also



References

Bibliography

  • (2006): A nuclear DNA phylogeny of the woolly mammoth (Mammuthus primigenius). Molecular Phylogenetics and Evolution 40 (2) 620–627. (HTML abstract). Supplemental data available to subscribers.
  • (2006): Clashing with Titans. BioScience 56(4): 292-298. DOI:10.1641/0006-3568(2006)56[292:CWT]2.0.CO;2 PDF fulltext
  • (1994): Mammoths. MacMillan, London. ISBN 0-02-572985-3
  • (2005): Twilight of the mammoths: Ice Age extinctions and the rewilding of America. University of California Press, Berkeley. ISBN 0-520-23141-4
  • (1885): The Lenape Stone or The Indian and the Mammoth. DjVu fulltext PDF fulltext
  • (2001): Mammoth: The resurrection of an Ice Age giant. Fourth Estate, London. ISBN 1-84115-518-7


Notes

  1. Oxford English Dictionary:Mammoth (2000).
  2. Recently discovered long Woolly Mammoth tusk on display at the Illinois State Museum Illinois Department of Natural Resources press release, August 14, 2006
  3. Anthony J. Stuart, Leopold D. Sulerzhitsky, Lyobov A. Orlova, Yaroslav V. Kuzmin and Adrian M. Lister: The latest woolly mammoths (Mammuthus primigenius Blumenbach) in Europe and Asia: a review of the current evidence Quaternary Science Reviews Volume 21, Issues 14-15, August 2002, Pages 1559-1569 online
  4. Kristine J. Crossen, “5,700-Year-Old Mammoth Remains from the Pribilof Islands, Alaska: Last Outpost of North America Megafauna”, Geological Society of America Abstracts with Programs, Volume 37, Number 7, (Geological Society of America, 2005), 463.
  5. David R. Yesner, Douglas W. Veltre, Kristine J. Crossen, and Russell W. Graham, “5,700-year-old Mammoth Remains from Qagnax Cave, Pribilof Islands, Alaska”, Second World of Elephants Congress, (Hot Springs: Mammoth Site, 2005), 200-203
  6. Kh. A. Arslanov, G. T. Cook, Steinar Gulliksen, D.D. Harkness, Touvi Kankainen, E. M. Scott, Sergey Vartanyan, and Ganna I. Zaitseva, S. L. Vartanyan, “Consensus Dating of Remains from Wrangel Island”, Radiocarbon, Volume 40, Number 1, (Tucson: Radiocarbon, 1998), 289-294.
  7. Sergei L. Vartanyan, Alexei N. Tikhonov, and Lyobov A. Orlova, “The Dynamic of Mammoth Distribution in the Last Refugia in Beringia”, Second World of Elephants Congress, (Hot Springs: Mammoth Site, 2005), 195.


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