Pygmy mammoth
| Pygmy mammoth Temporal range: Late to Early Holocene, 0.06–0.011 Ma |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Proboscidea |
| Family: | Elephantidae |
| Genus: | Mammuthus |
| Species: | M. exilis |
| Binomial name | |
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Mammuthus exilis (Stock & Furlong, 1928) |
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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) of mainland North America. This species became extinct during the Quaternary extinction event in which many megafauna species became extinct due to changing conditions to which the species could not adapt. 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, in stark contrast to its 4.3 m (14 ft) tall, 9,070 kg (20,000 lb) ancestor. Another estimate gives a shoulder height of 2.02 m (6.6 ft) and a weight of 1,350 kg (2,980 lb).
Mammoth remains have been known on the northern Channel Islands of California since 1856. They were first reported in scientific literature in 1873.
In 1994 the National Park Service called in scientists to inspect an uncovered, unidentified skeleton found on the northeast coast of Santa Rosa Island. They found bones of the axial skeleton of a large land vertebrate on the Santa Rosa Island. They decided there was enough evidence to start to excavate and dig up the skeleton. They recovered 90% of a mature male pygmy mammoth's skeleton. The mammoth was about 50 years old when it died. The small bones were preserved in life position, which represented that it had died where it was found rather than being scattered around the island. The bones were returned to the Santa Barbara Museum of Natural History. After the discovery of the skeleton, a pedestrian survey of the island was started, which resulted in the discovery of 160 new locations of mammoth remains, the vast majority being found on Santa Rosa Island. This was the first discovery of a nearly complete specimen of the pygmy mammoth. Fortunately enough, the skeleton of the mammoth was only missing a foot, a tusk, and a couple of vertebrae. The remains were covered by a sand dune, which prevented the bones from scattering and kept them intact.
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 elephant appears to have survived on the islands until the arrival of the humans associated with Arlington Springs Man around 13,000 years ago and the last known mammoth occurrence was 13–12.9 thousand years ago which predates the later Chumash people's arrival 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).
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