The woolly Mammoth, Mammuthus primigenius (1799)
Phylum : Chordata
Class : Mammalia
Order : Proboscidea
Family : Elephantidae
Genus : Mammuthus
Species : M. primigenius
- Pleistocene/Early Holocene (15 000 - 4 000 years ago)
- 5,4 m long and 6 000 kg (size)
- Eurasia (map)
The earliest known proboscideans, the clade which contains elephants, existed about 55 million years ago around the Tethys Sea. The closest known relatives of the Proboscidea are the sirenians and the hyraxes. The family Elephantidae existed six million years ago in Africa and includes the modern elephants and the 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.
Adult woolly mammoths could effectively defend themselves from predators with their tusks, trunks and size, but juveniles and weakened adults were vulnerable to pack hunters such as wolves, cave hyenas and large felines. The tusks may also have been used in intra-species fighting, such as territorial fights or fights over mates. Because of their curvature, the tusks were not suitable for stabbing, but may have been used for hitting, as indicated by injuries to some fossil shoulder blades. As in modern elephants, the sensitive and muscular trunk worked as a limb-like organ with many functions. It was used for manipulating objects, and in social interactions. The very long hairs on the tail probably compensated for the shortness of the tail, enabling its use as a flyswatter, similar to the tail on modern elephants. As in reindeer and musk oxen, the haemoglobin of the woolly mammoth was adapted to the cold, with three mutations to improve oxygen delivery around the body and prevent freezing. This feature may have helped the mammoths to live in high latitudes.
Like modern elephants, woolly mammoths were likely very social and lived in matriarchal family groups. This is supported by fossil assemblages and cave paintings showing groups. It is therefore probable that most of their other social behaviour was similar to those of modern elephants. Accumulations of modern elephant remains have been termed “elephants’ graveyards”, as these sites were erroneously thought to be where old elephants went to die. Similar accumulations of woolly mammoth bones have been found; it is thought these are the result of individuals dying near or in the rivers over thousands of years, and their bones eventually being brought together by the streams, or due to animals being mired in mud. Some accumulations are also thought to be the remains of herds that died together at the same time, perhaps due to flooding.
Trackways made by a woolly mammoth herd 11,300–11,000 years ago, have been found in the St. Mary Reservoir in Canada, showing that there were in this case almost equal numbers of adults, sub-adults and juveniles. The adults had a stride of 2 m, and the juveniles ran to keep up. The well-preserved foot of the adult male “Yukagir mammoth” shows that the soles of the feet contained many cracks that would have helped in gripping surfaces during locomotion. Like modern elephants, woolly mammoths walked on their toes and had large, fleshy pads behind the toes.
Evidence of several different bone diseases has been found in woolly mammoths. The most common of these diseases was osteoarthritis, found in 2% of specimens. One specimen from Switzerland had several fused vertebrae as a result of this condition. The “Yukagir mammoth” had suffered from spondylitis in two vertebrae, and osteomyelitis is also known from some specimens. Several specimens have healed bone fractures, showing that the animals had survived these injuries. Parasitic flies and protozoa were identified in the gut of the calf “Dima”.