A mammoth is any species of the extinct genus Mammuthus. These proboscideans are members of the elephant family 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 4.8 million years ago to around 4,500 years ago. The word mammoth comes from the Russian мамонт mamont, probably in turn from the Vogul (Mansi) language.
A definitive explanation for their mass extinction is yet to be agreed upon. About 12,000 years ago, warmer, wetter weather was beginning to take hold. Rising sea levels swamped the coastal regions. Forests replaced open woodlands and grasslands across the continent. The Ice Age was ebbing. As their habitats disappeared, so did the bison and the mammoth.
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 is the most likely explanation for their extinction.
New data derived from studies done on living elephants (see Levy 2006) suggests that though human hunting may not have been the primary cause for the mammoth's final extinction, human hunting was likely a strong contributing factor. Homo erectus is known to have consumed mammoth meat as early as 1.8 million years ago (Levy 2006: 295).
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's Wrangel Island was because the island was very remote and uninhabited in the early Holocene period. The actual island was not discovered by modern civilization until the 1820s by American whalers. A similar dwarfing occurred with the Pygmy Mammoth on the outer Channel Islands of California, 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 the Santa Rosae into the outer Channel Islands.
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, the Imperial Mammoth of California, reached heights of at least 5 metres (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. A long mammoth tusk was discovered north of Lincoln, Illinois 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 Islands (Mammuthus exilis) and the Mediterranean island of Sardinia (Mammuthus lamarmorae). There was also a race of dwarf woolly mammoths on Wrangel Island, 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.