Pygmy mammoth
| Pygmy mammoth Temporal range: Late Pleistocene to Early Holocene,
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| Species: | M. exilis
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| Mammuthus exilis (Stock & Furlong, 1928)[1]
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The pygmy mammoth or Channel Islands mammoth (Mammuthus exilis) is an extinct species of dwarf elephant descended from the Columbian mammoth (M. columbi). A case of island or insular dwarfism, from a recent analysis in 2010 it was determined that M. exilis was on average, 1.72 m (5.6 ft) tall at the shoulders and 760 kg (1,680 lb) in weight.[2] A stark contrast to its 4.3 m (14 ft) tall, 9,100 kg (20,100 lb) ancestor.[3]
Remains of M. exilis have been discovered on three of the northern Channel Islands of California since 1856: Santa Cruz, Santa Rosa, and San Miguel, which together with Anacapa were the highest portions of the now mostly submerged superisland of Santa Rosae. The late Pleistocene elephant may have lived on the islands until the arrival of the Chumash people during the early Holocene, between 10,800 and 11,300 years ago. Radiocarbon dating indicates M. exilis existed on the island for at least 47,000 years prior (which is the approximate limit of the dating method).[4]
Modern elephants are excellent swimmers, and the ancestors of M. exilis most likely swam the 4 mi (6.4 km) to Santa Rosae. As the population of mammoths increased, the lack of large predators and the loss of habitat caused by the rise of sea levels at the end of the ice age as Santa Rosae split into four islands favored smaller animals.[3]
M. exilis should not be confused with the mammoths of Wrangel Island or Saint Paul Island, which were small races of the woolly mammoth (M. primigenius) and which died out around 1700 B.C. and 4000 B.C., respectively.
See also
1994 Discovery
In June 1994 Tom Rockwell and Kevin Colson found bones representing the axial skeleton of a large land vertebrate on the Santa Rosa Island. On August 1994, they decided there was enough evidence to start excavate and salvage the skeleton. They recovered 90% of a mature male Pygmy Mammoth's skeleton. The small bones were preserved in life position, which indicated it had died where it was found rather than being scattered around. The bones were returned to the Santa Barbara Museum of Natural History. Cite error: There are <ref> tags on this page without content in them (see the help page). http://doc.rero.ch/record/31563/files/PAL_E647.pdf#page=35
References
- ^ Chester Stock and E. L. Furlong (1928). "The Pleistocene elephants of Santa Rosa Island, California". Science. 68 (1754): 140–141. Bibcode:1928Sci....68..140S. doi:10.1126/science.68.1754.140.
- ^ Agenbroad, L. D. (2010). ". Mammuthus exilis from the California Channel Islands: Height, Mass and Geologic Age" (PDF). Proceedings of the 7th California Islands Symposium. p. 17. Retrieved 13 June 2012.
- ^ a b "The pygmy mammoth". Channel Islands National Park. U.S. Department of the Interior National Park Service. 2006-09-01. Retrieved 2008-06-14.
- ^ Agenbroad, L. D. (2001-10-19). "Channel Islands (USA) pygmy mammoths (Mammuthus exilis) compared and contrasted with M. columbi, their continental ancestral stock" (PDF). La terra delgli Elefanti: Atti del 1st Congresso Internazionale (The World of Elephants: Proceedings of the 1st International Congress). Roma: Consiglio Nazionale delle Ricerche. pp. 473–475. ISBN 88-8080-025-6. Retrieved 2008-06-14.
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