American mastodon

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American mastodon
American mastodon skeleton

American mastodon skeleton

Temporal occurrence
Pliocene to Late Pleistocene
10 million years to 10,000 years
Locations
Systematics
Tethytheria
Russell animals (Proboscidea)
Elephantimorpha
Mammutids (Mammutidae)
mammoth
American mastodon
Scientific name
Mammoth americanum
( Kerr , 1792)

The American mastodon ( Mammut americanum ; plural: American mastodons) is a species of proboscis from the extinct genus Mammut , a relatives of the mammutids (Mammutidae; in German sometimes also called "real mastodons"). It lived in North America from the early Pliocene to the beginning of the Holocene . Regardless of its name, the genus Mammut is not closely related to the mammoths (genus name Mammuthus ) - for a while the genus Mammut was called Mastodon , but the name Mammut is still valid. The American mastodon was first described by Robert Kerr in 1792 with the scientific name Elephas americanus . In 2019, the western population was separated as a separate species under the name Mammut pacificus .

Original skeletons of American mastodons are in numerous museums, including a. in the Senckenberg Natural History Museum in Frankfurt am Main.

distribution

The genus mammoth was widespread in Eurasia and Africa from the early Miocene to the beginning of the Pleistocene and appeared in North America from around the middle Miocene. This is where the American mastodon ( Mammut americanum ) formed, which survived until the arrival of the first humans and only died out at the beginning of the Holocene, 9,000 to 12,000 years ago. One of the recent discoveries is the Overmyer mastodon from Indiana , which is a radiometric has aged 10,032 years ago. This species of proboscis inhabited almost the entire North American continent and was found everywhere between Alaska and Mexico . Their southernmost occurrence so far is an isolated find from Honduras . The American mastodon was particularly common on the east coast and in the Great Lakes area, presumably because woody habitats were more appealing to it than the grassy areas of the west. In the western part of the continent the species was replaced by the mammoth pacificus , which appeared at the same time . The shape is proven there especially in present-day California , some finds also come from southern Idaho .

Appearance

Live reconstruction of an American mastodon
Tooth, side view
Tooth, view of the chewing surface

In terms of habit, the American mastodon differed significantly from the mammoths that lived in the same area at the same time. At 2.7 to 3.4 m shoulder height it was significantly lower than this, but longer (up to 4.5 m) and stockier. As a result, it could weigh 6.5 to 9 t, which roughly corresponded to that of a mammoth. The tusks were curved up a little. The most important feature of the American mastodon, however, were its primeval teeth. In contrast to mammoths and elephants , it had the typical teeth of the original mammoths. With their cone-shaped tips, they were ideal for crushing branches and leaves, but the animal could not crush larger amounts of grass with them. The American mastodon may have had fur; rare finds of hair have come from the Milwaukee Mastodon Site near Milwaukee in the US state of Wisconsin , which adhered to some skull fragments together with remains of skin.

Way of life

As its tooth structure reveals, the American mastodon was a leaf and twig eater that ate branches as well as leaves and needles. This assumption is corroborated by the findings of some teeth on which there were remains of coniferous branches. In addition, marsh plants such as mermaid herbs , pondweed plants or water lilies and mosses were found between the teeth. Fossilized stomach and intestinal contents, so u. a. from the Burning Tree mastodon from Ohio and from the Heisler mastodon from Michigan , also contained remains of leaves, twigs and fruits, such as spruce , birch , willow , ash and pine , as well as various grasses such as sedges and swaths or herbs , for example spawning herbs and fever clover . The animals also swallowed mushrooms and invertebrates rather than “bycatch”. Because of this diet and also because of the increased number of finds in the damp east of the North American continent, it is assumed that this mastodon was primarily a forest dweller and left the open prairies to the mammoths. Nevertheless, its large distribution area suggests that it was a very adaptable animal that probably got along in savannas and forest steppes . Since powerful predators such as short-faced bears , saber-toothed cats and lions hunted in North America at the time of the American mastodon , it must have lived in herds, if only to be able to better defend the calves. Possibly it lived similar to today's elephants.

die out

The American mastodon was a highly successful species that survived for millions of years. It even withstood competition from the mammoths who later immigrated and lived successfully alongside them for a long time. When the last glacial period came to an end, like many other large animal species, it died out. There are various theories about the reasons for the extinction .

At the time of extinction, the first humans appeared in America and there is evidence to suggest that they preyed upon the mastodon. A bony spearhead is stuck in the rib of an American mastodon that was discovered in 1977 on the Olympic Peninsula in Washington State . The animal initially survived this attack, which can be seen from the fact that the injury was able to heal, but was later slaughtered by humans. Its bones are estimated to be around 14,000 years old. A few thousand years later, the species was extinct across North America. This suggests that humans could have exterminated the American mastodon along with many other large animal species through overhunting ( overkill hypothesis ).

Another possible cause could have been climate change at the end of the Pleistocene . One study named the profound climate changes as the main cause, but only for a separate region in Alaska. When the forests there were replaced by tundra cover around 70,000 years ago , to which the American mastodon was probably not adapted, this could have contributed to its extinction. This event does not coincide with the discussed extinction wave about 10,000 years ago in southern North America.

Others point out that pathogens could have been introduced by humans or animals or pets following them. The populations of large animals, which could not adapt to change quickly enough because of their long generation times, were additionally weakened. A tuberculosis epidemic is being considered as a possible cause of the extinction. Of 113 specimens examined, 59 showed symptoms on their leg bones that are typical of tuberculosis. This indicates a high proportion of infected animals. American mastodons may have lived with this disease for millennia, so it may not be the sole cause of its disappearance. Some researchers suggest that the disease over many generations chronically ran until the load in combination with stress as a result of environmental deterioration and the hunting by the immigrant glacial people on hand took.

literature

Web links

Commons : American Mastodon ( Mammut americanum )  - Collection of images, videos, and audio files

Individual evidence

  1. ↑ a b c Jeffrey J. Saunders: North American Mammutidae. In: Jeheskel Shoshani, Pascal Tassy (Ed.): The Proboscidea. Evolution and palaeoecology of the Elephants and their relatives. Oxford / New York / Tokyo, 1996, pp. 271-279.
  2. ^ Neal Woodman, John W. Branstrator: The Overmyer mastodon (Mammut americanum) from Fulton County. Indiana. In: American Midland Naturalist . 159, 2008, pp. 125-146.
  3. ^ Neal Woodman, Nancy Beavan Athfield: Post-Clovis survival of American Mastodon in the southern Great Lakes Region of North America. In: Quaternary Research . 72, 2009, pp. 359-363.
  4. ↑ Spencer G. Lucas and Guillermo E. Alvarado: Fossil Proboscidea from the Upper Eozoic of Central America: Taxonomy, evolutionary and paleobiogeographic significance. In: Revista Geológica de América Central . 42, 2010, pp. 9-42.
  5. ↑ Alton C. Dooley Jr, Eric Scott, Jeremy Green, Kathleen B. Springer, Brett S. Dooley, and Gregory James Smith: Mammut pacificus sp. nov., a newly recognized species of mastodon from the Pleistocene of western North America. PeerJ 7, 2019, p. E6614, doi: 10.7717 / peerj.6614
  6. ↑ Asier Larramendi: Shoulder height, body mass and shape of proboscideans. Acta Palaeontologica Polonica 61 (3), 2016, pp. 537-574, doi: 10.4202 / app.00136.2014 .
  7. ↑ Kimberley Sawtelle: Mastodont hair gives clues to habitat. Mammoth Trumpet 6 (4), 1991, p. 8.
  8. ^ Jan van der Made: The evolution of the elephants and their relatives in the context of a changing climate and geography. In: Harald Meller (Hrsg.): Elefantenreich - Eine Fossilwelt in Europa. Halle / Saale, 2010, pp. 340-360.
  9. ↑ Hilary H. Birks, Bas van Geel, Daniel C. Fisher, Eric C. Grimm, Wim J. Kuijper, Jan van Arkel and Guido BA van Reenen: Evidence for the diet and habitat of two late Pleistocene mastodons from the Midwest, USA . Quaternary Research, 2018, pp. 1–21, doi: 10.1017 / qua.2018.100 .
  10. ↑ Michael R. Waters, Thomas W. Stafford Jr., H. Gregory McDonald, Carl Gustafson, Morten Rasmussen, Enrico Cappellini, Jesper V. Olsen, Damian Szklarczyk, Lars Juhl Jensen, M. Thomas P. Gilbert, Eske Willerslev: Pre -Clovis mastodon hunting 13,800 years ago at the Manis site, Washington. In: Science , Volume 334, October 21, 2011, pp. 351-353, doi : 10.1126 / science.1207663 .
  11. ↑ Grant D. Zazula, Ross DE MacPhee, Jessica Z. Metcalfe, Alberto V. Reyes, Fiona Brock, Patrick S. Druckermiller, Pamela Groves, C. Richard Harington, Gregory WL Hodgins, Michael L. Kunz, Fred J. Longstaffe, Daniel H. Mann, H. Gregory McDonald, Shweta Nalawade-Chavan, John R. Southon: American mastodon extirpation in the Arctic and Subarctic predates human colonization and terminal Pleistocene climate change. In: PNAS , Volume 111, No. 52, 2014, pp. 18460-18465, doi : 10.1073 / pnas.1416072111 .
  12. ↑ Bruce Rothschild and Richard Laub: Hyperdisease in the late Pleistocene: validation of an early 20th century hypothesis. Natural Sciences 93 (11), 2006, pp. 557-564.