Primeval: More Facts About The Columbian Mammoth (Mammuthus columbi) aka Monty That Lester Probably
1909 restoration by Charles R. Knight, based on the AMNH specimen
Morphology:
The Columbian mammoth could reach 4m (13 ft) at the shoulder and weighed up to 10 tonnes (22,000lbs) - larger than both the woolly mammoth and the African elephant, both of which reached about 2.7 - 3.4 m (8.9 - 11.2 ft). Males were generally larger and more robust than the females, although the best indicator of sex is the size of the pelvic girdle (wider in females than males). Like other mammoths, the Columbian had a high, single-domed head and a sloping back with a high shoulder hump, a result of the spinal processes of the vertebrae decreasing in length. However, calves had convex backs similar to Asian elephants.
Skeleton of a juvenile at the Natural History Museum of Utah
Little is known about their appearance due to a lack of soft tissue, but as they lived south of the woolly mammoths, in warmer climes, it can be assumed they lacked many of that species adaptations to the cold. The tail's length was intermediate between that of modern elephants and the woolly mammoth.
Red hair positively identified as coming from a Columbian mammoth has been discovered in the Bechan Cave in Utah. Although it is coarse and identical to that of the woolly mammoth, it comes from an area far south of their range and is unlikely to belong to a woolly mammoth. How the hair was distribution over the animal and how dense it was is unknown, but it probably had less than the woolly mammoth due to its warmer habitat.
Dentition including tusks:
They had four functional molars at a time - two in the upper jaw and two in the lower - which were replaced 5 times. About 9/10th of the tooth was within the jaw and the crown was pushed upwards and forwards as it was worn. The tooth consisted of quite wear resistant ridges of enamel covered in 'prisms' held together of cementum and dentine. The molars grew larger and had more ridges with each set - the first set was about the size of a human molar (1.3cm/0.51”), the six (and last) was 30cm (1 ft) long and weighed 1.8kgs. The number of ridges increased with each set and varied across individuals. The second set erupted at 6-24 months of age, the last set at 30 and the mammoth died of starvation when its teeth wore out.
Underside of the skull of a male La Brea specimen nicknamed "Zed", showing upper molars
The Columbian mammoth had very long tusks (modified incisor teeth), typically more curved than those of modern elephants. The largest known mammoth tusk belonged to a Columbian and measured 4.9m (16 ft) long, although others ranged between 3.5m (11 ft) and 4.121m (13.52 ft). Most were about the same length as those found in woolly mammoths (4.2m or 14 ft). The tusks of females were much smaller and thinner. About a quarter of the length was within the socket and the tusks grew spirally in opposite directions and continued in a curve until the tips pointed at each other, sometimes crossing. This kept most of the weight near to the skull and the spiralling reduced the torque (rotational force on the tusks).
The tusks were usually asymmetrical and showed considerable variation, with some curved down instead of outwards and some were shorter due to breakage. Columbian mammoth tusks were usually less twisted than those of the woolly mammoths. Calves developed milk tusks of a few centimetres long at six months, replacing them with permanent tusks a year later. Tusks continued to grown throughout their lives and grew by 2.5 to 15cm (0.98 to 5.91”) each year, slowing when the animal reached adulthood.
The tusks might have been used in intra-species fighting, e.g. territorial fights or over mates. Displays of large tusks by the males could have been used to attract females and to intimidate rivals. Because of their curvature, the tusks were not suitable for stabbing, instead they might have thrust, swiped or crashed them into their target. Evidence for fighting comes from two Columbian mammoths found in Nebraska who died with their tusks interlocked.
Growth:
Modern elephants have gestation periods of 21-22 months, and Columbian might have as well. The lifespan of mammals is related to their size - modern elephants can reach 60, it is believed woolly mammoths (of a similar size) did as well, while the larger Columbian could have lived to 80. The age of a mammoth can be approximately determined by counting the growth rings in the tusks, although the earliest years are not represented due to the tips usually being worn off. Each major line represented a year, and weekly and daily ones are found between them. Dark bands correspond to summer so the time of year a mammoth died can be determined. Mammoths continued to grow past adulthood, unfused limb bones show that males grew until 40 and females until 25.
Adult mammoths could effectively defend themselves from predators with their tusks, trunks and size, but juveniles and weakened adults were vulnerable to predators such as sabre-toothed cats (Smilodon and Homotherium), the American lion (Panthera atrox) and the Short-Faced bear (Arctodus).
Interesting (and miscellaneous) facts:
1) The pygmy mammoths of the Channel Islands, California were half the size of their mainland relatives and are considered either a separate species or subspecies of the Columbian mammoth. As these islands were never linked to the mainland, it supports the idea that the mammoths were good swimmers.
2) Nick (in 2.6) said the Columbian was the biggest elephant that ever lived - at least some of the websites suggest that the Steppes mammoth was bigger. And if we go for elephants, the Asian straight-tusked elephant (Palaeoloxodon namadicus) had a possible height of 5.2m at the shoulder and 22 tonnes in weight, although not enough fossils have been discovered to confirm these measurements.
References:
http://eol.org/pages/4454743/details - Encyclopedia of life
https://en.wikipedia.org/wiki/Columbian_mammoth
http://www.prehistoric-wildlife.com/species/m/mammuthus-columbi-columbian-mammoth.html
http://dinopedia.wikia.com/wiki/Columbian_mammoth
Palaeoloxodon namadicus - https://en.wikipedia.org/wiki/Palaeoloxodon_namadicus
https://www.smithsonianmag.com/smart-news/rare-mammoth-hair-found-californian-artichoke-farm-180952624/
http://westerndigs.org/first-columbian-mammoth-with-hair-discovered-on-california-farm/