Mammoth

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A mammoth is any species of the extinct elephantid genus Mammuthus. They lived from the late Miocene epoch (from around 6.2 million years ago) into the Holocene until about 4,000 years ago, with mammoth species at various times inhabiting Africa, Asia, Europe, and North America. Mammoths are distinguished from living elephants by their (typically large) spirally twisted tusks and in some later species, the development of numerous adaptions to living in cold environments, including a thick layer of fur.

Mammoths and Asian elephants are more closely related to each other than they are to African elephants. The oldest mammoth representative, Mammuthus subplanifrons, appeared around 6 million years ago during the late Miocene in what is now southern and Eastern Africa.<ref name=":22">Template:Cite book</ref> Later in the Pliocene, by about three million years ago, mammoths dispersed into Eurasia, eventually covering most of Eurasia before migrating into North America around 1.5–1.3 million years ago, becoming ancestral to the Columbian mammoth (M. columbi). The woolly mammoth (M. primigenius) evolved about 700–400,000 years ago in Siberia, with some surviving on Russia's Wrangel Island in the Arctic Ocean until as recently as 4,000 years ago, still extant during the existence of the earliest civilisations in ancient Egypt and Mesopotamia.

Etymology and early observationsEdit

According to The American Heritage Dictionary, the word "mammoth" likely originates from *mān-oŋt, a word in the Mansi languages of western Siberia meaning "earth horn", in reference to mammoth tusks.<ref>“mammoth”, in The American Heritage Dictionary of the English Language, 5th edition, Boston, Mass.: Houghton Mifflin Harcourt, 2016, →ISBN.</ref> Mammoths appear in the folklore of the indigenous people of Siberia, who were impressed by the great size of their remains. In the mythology of the Evenk people, mammoths were responsible for the creation of the world, digging up the land from the ocean floor with their tusks. The Selkup believed that mammoths lived underground and guarded the underworld, while the Nenets and the Mansi (the latter of whom, along with the Khanty, conceived mammoths as giant birds) believed that mammoths were responsible for the creation of mountains and lakes, while the Yakuts regarded mammoths as water spirits.<ref name=":10">Template:Cite journal</ref>

The word mammoth was first used in Europe during the early 17th century, when referring to maimanto tusks discovered in Siberia,<ref>Template:Cite book</ref> as recorded in the 1618 edition of the Dictionariolum Russico-Anglicum.<ref>"Mammoth" Oxford English Dictionary 2000</ref> The earliest scientific research paper on mammoths was by Vasily Tatishchev in 1725.<ref name=":10" /> John Bell, who was on the Ob River in 1722, said that mammoth tusks were well known in the area. They were called "mammon's horn" and were often found in washed-out river banks. Bell bought one and presented it to Hans Sloan who pronounced it an elephant's tooth.<ref>John Bell, Travels from St Petersburg in Russia to diverse parts of Asia, Edinburgh, 1806, pages 383-386</ref>

In the American colonies around 1725, enslaved Africans digging in the vicinity of the Stono River in South Carolina unearthed molar teeth recognised in modern times to belong to Columbian mammoths, with the remains subsequently examined by the British naturalist Mark Catesby, who visited the site, and later published an account of his visit in 1843. While the slave owners were puzzled by the objects and suggested that they originated from the great flood described in the Bible, Catesby noted that the slaves unanimously agreed that the objects were the teeth of elephants similar to those from their African homeland, to which Catesby concurred, marking the first technical identification of any fossil animal in North America.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Cite journal</ref>

In 1796, French biologist Georges Cuvier was the first to identify woolly mammoth remains not as modern elephants transported to the Arctic, but as an entirely new species. He argued this species had gone extinct and no longer existed, a concept that was not widely accepted at the time.<ref name="Switek">Template:Cite book</ref><ref name="cuvier1796">Template:Cite journal</ref> Following Cuvier's identification, German naturalist Johann Friedrich Blumenbach gave the woolly mammoth its scientific name, Elephas primigenius, in 1799, placing it in the Elephas, the genus which today contains the Asian elephant (Elephas maximus). Originally the African elephants, as well as the American mastodon (described in 1792) were also placed in Elephas. Cuvier coined the synonym Elephas mammonteus for the woolly mammoth a few months later, but E. primigenius became the widely used name for the species, including by Cuvier.<ref name="Lectotypes">Template:Cite journal</ref> The genus name Mammuthus was coined by British anatomist Joshua Brookes in 1828, as part of a survey of his museum collection.<ref>BROOKES, J., 1828. A catalogue of the anatomical and zoological museum of Jeshua Brookes, Esq., F.R.S. etc. Part 1. R.Taylor, London. 76 pp.</ref>

Thomas Jefferson, who famously had a keen interest in paleontology, is partially responsible for transforming the word mammoth from a noun describing the prehistoric elephant to an adjective describing anything of surprisingly large size. The first recorded use of the word as an adjective was in a description of a large wheel of cheese (the "Cheshire Mammoth Cheese") given to Jefferson in 1802.<ref name="oed">Simpson, J. (2009). "Word Stories: Mammoth Template:Webarchive." Oxford English Dictionary Online, Oxford University Press. Accessed 05-JUN-2009.</ref>

EvolutionEdit

The earliest known proboscideans, the clade that contains the elephants, arose about 55 million years ago on the landmass of Afro-Arabia. The closest relatives of the Proboscidea are the sirenians and the hyraxes. The family Elephantidae arose a million years ago in Africa, including the living elephants and 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.<ref name="Lister 2007">Template:Cite book</ref>

Following the publication of the woolly mammoths mitochondrial genome sequence in 1997, it has since become widely accepted that mammoths and Asian elephants share a closer relationship with each other than either do to African elephants.<ref>Template:Cite journal</ref><ref name=":52" />

The following cladogram shows the placement of the genus Mammuthus among other proboscideans, based on hyoid characteristics and genetics:<ref name="Shoshani_etal_2007">Template:Cite journal</ref><ref name=":52">Template:Cite journal</ref>

Template:Clade It is possible to reconstruct the evolutionary history of the genus through morphological studies. Mammoth species can be identified from the number of enamel ridges/lamellae on their molars; the primitive species had few ridges, which increased gradually as new species evolved and replaced the former ones. At the same time, the crowns of the teeth became longer, and the skulls became higher from top to bottom and shorter from the back to the front over time to accommodate this.<ref name="Mammoth evolution">Template:Cite journal</ref>

The earliest mammoths, assigned to the species Mammuthus subplanifrons, are known from southern and eastern Africa, with the earliest records dating to the Late Miocene, around 6.2–5.3 million years ago.<ref name=":22" /> By the Late Pliocene, mammoths had become confined to the northern portions of the African continent with remains from this time assigned to Mammuthus africanavus.<ref name=":2">Template:Cite book</ref> During the Late Pliocene, by 3.2 million years ago, mammoths dispersed into Eurasia via the Sinai Peninsula. The earliest mammoths in Eurasia are assigned to the species Mammuthus rumanus.<ref>Template:Cite journal</ref> The youngest remains of mammoths in Africa are from Aïn Boucherit, Algeria dating to the Early Pleistocene, around 2.3–2 million years ago (with a possible later record from Aïn Hanech, Algeria, dating to 1.95–1.78 million years ago).<ref name=":2" />

Mammuthus rumanus is thought to be the ancestor of Mammuthus meridionalis, which first appeared at the beginning of the Pleistocene, around 2.6 million years ago.<ref name=":3">Template:Cite journal</ref> Mammuthus meridionalis subsequently gave rise to Mammuthus trogontherii (the steppe mammoth) in Eastern Asia around 1.7 million years ago. Around 1.5–1.3 million years ago, M. trogontherii crossed the Bering Land Bridge into North America, becoming ancestral to Mammuthus columbi (the Columbian mammoth).<ref>Template:Cite journal</ref> At the end of the Early Pleistocene Mammuthus trogontherii migrated into Europe, replacing M. meridionalis around 1–0.8 million years ago.<ref name=":3" /> Mammuthus primigenius (the woolly mammoth) had evolved from M. trogontherii in Siberia by around 600,000–500,000 years ago, replacing M. trogontherii in Europe by around 200,000 years ago, and migrated into North America during the Late Pleistocene.<ref name="Lister 107693">Template:Cite journal</ref>

Several dwarf mammoth species, with small body sizes, evolved on islands as a result of insular dwarfism. These include Mammuthus lamarmorai on Sardinia (late Middle-Late Pleistocene),<ref name=":02">Template:Cite journal</ref> Mammuthus exilis on the Channel Islands of California (Late Pleistocene),<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and Mammuthus creticus on Crete (Early Pleistocene).<ref name=":1">Template:Cite journal</ref>

DescriptionEdit

Template:See also Like living elephants, mammoths typically had large body sizes. The largest known species like Mammuthus meridionalis and Mammuthus trogontherii (the steppe mammoth) were considerably larger than modern elephants, with mature adult males having an average height of approximately Template:Convert at the shoulder and weights of Template:Convert, while exceptionally large males may have reached Template:Convert at the shoulder and Template:Convert in weight.<ref name="probos_mass">Template:Cite journal</ref> However, woolly mammoths were considerably smaller, only about as large as modern African bush elephants with males around Template:Convert high at the shoulder, and Template:Convert in weight on average,<ref name=":54">Template:Cite journal</ref> with the largest recorded individuals being around Template:Convert tall and Template:Convert in weight.<ref name="probos_mass" /> The insular dwarf mammoth species were considerably smaller, with the smallest species M. creticus estimated to have a shoulder height of only around Template:Convert and a weight of about Template:Convert, making it one of the smallest elephantids known.<ref name="probos_mass" />

The number of lamellae (ridge-like structures) on the molars, particularly on the third molars, substantially increased over the course of mammoth evolution. The earliest Eurasian species M. rumanus have around 8-10 lamellae on the third molars,<ref>Template:Cite journal</ref> while Late Pleistocene woolly mammoths have 20-28 lamellae on the third molars. These changes also corresponded with reduced enamel thickness and increasing tooth height (hypsodonty).<ref name="Lister 107693" /> These changes are thought to be adaptations to increasing abrasion resulting from the shift in the diet of mammoths from a browsing based diet in M. rumanus, towards a grazing diet in later species.<ref>Template:Cite journal</ref><ref name=":4">Template:Cite journal</ref>

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Both sexes bore tusks. A first, small set appeared at about the age of six months, and these were replaced at about 18 months by the permanent set. Growth of the permanent set was at a rate of about Template:Convert per year.<ref>Template:Cite book</ref> The tusks display a strong spiral twisting.<ref>Template:Cite journal</ref> Mammoth tusks are among the largest known among proboscideans with some specimens over Template:Convert in length and likely Template:Convert in weight with some historical reports suggesting tusks of Columbian mammoths could reach lengths of around Template:Convert substantially surpassing the largest known modern elephant tusks.<ref>Template:Cite journal</ref>

The heads of mammoths were prominently domed.<ref name=":53">Template:Cite journal</ref> The first several thoracic vertebrae of mammoths typically had long neural spines.<ref>Template:Cite journal</ref> The back was typically sloping, with the body being wider than that of African elephants. The tails of mammoths were relatively short compared to living elephants.<ref name=":53" />

File:Woolly mammoth model Royal BC Museum in Victoria.jpg

Life restoration of a woolly mammoth at Royal BC Museum

While early mammoth species like M. meridionalis were probably relatively hairless, similar to modern elephants,<ref name="Giants">Template:Cite book</ref> M. primigenius and likely M. trogontherii had a substantial coat of fur, among other physiological adaptations for living in cold environments. Genetic sequencing of M. trogontherii-like mammoths, over 1 million years old from Siberia suggests that they had already developed many of the genetic changes found in woolly mammoths responsible for tolerance of cold conditions.<ref name=":03">Template:Cite journal</ref> Scientists discovered and studied the remains of a mammoth calf, and found that fat greatly influenced its form, and enabled it to store large amounts of nutrients necessary for survival in temperatures as low as Template:Convert.<ref name="Moore2008">Template:Cite book</ref> The fat also allowed the mammoths to increase their muscle mass, allowing the mammoths to fight against enemies and live longer.<ref>Template:Cite journal</ref> Woolly mammoths evolved a suite of adaptations for arctic life, including morphological traits such as small ears and tails to minimize heat loss, a thick layer of subcutaneous fat, and numerous sebaceous glands for insulation, as well as a large brown-fat hump like deposit behind the neck that may have functioned as a heat source and fat reservoir during winter.<ref>Template:Cite journal</ref>

Behaviour and palaeoecologyEdit

Template:See also Based on studies of their close relatives, the modern elephants and 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 living elephants, with females and juveniles residing in herds headed by a matriarch, whilst bulls lived solitary lives or formed loose groups after sexual maturity,<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> with analysis of testosterone levels in tusks indicating that adult males experienced periods of musth like modern elephants, where they entered a state of heightened aggression.<ref>Template:Cite journal</ref>

The earliest mammoth species like M. subplanifrons and M. rumanus were mixed feeders (both browsing and grazing) to browsers. Throughout mammoth evolution in Eurasia, their diet shifted towards mixed feeding-grazing in M. trogontherii, culminating in the woolly mammoth, which was largely a grazer, with stomach contents of woolly mammoths suggesting that they largely fed on grass and forbs. M. columbi is thought to have been a mixed feeder.<ref name=":4" />

Like living elephants, mammoth adults may have been largely invulnerable to non-human predation,<ref>Template:Cite journal</ref> though evidence has been found for the hunting of mammoth calves by predators, such as by the scimitar-toothed cat (Homotherium).<ref name="desantis etal 2021">Template:Cite journal</ref>

In living proboscideans, broken tusks sometimes occur during, for example, fights between males or when elephants of both sexes shove each other to reach critical resources such as water. The fracture surface of the remaining (rooted) tooth then becomes smoothed from use. It is very likely that this also occurred in extinct proboscideans such as mammoths as seen from a tusk found at Fenstanton Gravels (Cambs, UK) which still had some of the outer layers of cementum preserved and had a smooth, polished surface on an old, fractured surface ('faceting').<ref>Template:Cite journal</ref>

Relationship with early humansEdit

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Evidence that humans interacted with mammoths extends back to around 1.8 million years ago, with a number of bones of Mammuthus meridionalis from the Dmanisi site in Georgia having marks suggested to be the result of butchery by archaic humans, likely as a result of scavenging.<ref>Template:Cite journal</ref> During the Last Glacial Period, modern humans hunted woolly mammoths,<ref name=":6">Template:Cite journal</ref> used their remains to create art and tools,<ref name=":7">Template:Cite journal</ref><ref name=":6" /> and depicted them in works of art.<ref name=":7" /> Remains of Columbian mammoths at a number of sites suggest that they were hunted by Paleoindians, the first humans to inhabit the Americas.<ref name=":8" /> A possible bone engraving of a Columbian mammoth made by Paleoindians is known from Vero Beach, Florida.<ref>Template:Cite journal</ref>

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ExtinctionEdit

Template:Further Following the end of the Last Glacial Maximum, the range of the woolly mammoth began to contract, disappearing from most of Europe by 14,000 years ago.<ref name=":9">Template:Cite journal</ref> By the Younger Dryas (around 12,900-11,700 years Before Present), woolly mammoths were confined to the northernmost regions of Siberia. This contraction is suggested to have been caused by the warming induced expansion of unfavourable wet tundra and forest environments at the expense of the preferred dry open mammoth steppe, with the possible additional pressure of human hunting. The last woolly mammoths in mainland Siberia became extinct around 10,000 years ago, during the early Holocene.<ref name=":0">Template:Cite journal</ref> The final extinction of mainland woolly mammoths may have been driven by human hunting.<ref name=":9" /> Relict populations survived on Saint Paul island in the Bering Strait until around 5,600 years ago, with their extinction likely due to the degradation of freshwater sources,<ref>Template:Cite journal</ref> and on Wrangel Island off the coast of Northeast Siberia until around 4,000 years ago.<ref name=":0" />

The last reliable dates of the Columbian mammoth date to around 12,500 years ago.<ref>Template:Cite book</ref> Columbian mammoths became extinct as part of the end-Pleistocene extinction event where most large mammals across the Americas became extinct approximately simultaneously at the end of the Late Pleistocene.<ref>Template:Cite journal</ref> Hunting of Columbian mammoths by Paleoindians may have been a contributory factor in their extinction.<ref name=":8">Template:Cite journal</ref> The timing of the extinction of the dwarf Sardinian mammoth Mammuthus lamarmorai is difficult to constrain precisely, though the youngest specimen likely dates to sometime around 57–29,000 years ago.<ref name=":12">Template:Cite journal</ref> The youngest records of the pygmy mammoth (Mammuthus exillis) date to around 13,000 years ago, coinciding with the reducing of the area of the Californian Channel Islands as a result of rising sea level, the earliest known humans in the Channel Islands, and climatic change resulting in the decline of the previously dominant conifer forest ecosystems and expansion of scrub and grassland.<ref name=":13">Template:Cite journal</ref>

ReferencesEdit

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