The Teeth of Mammoths
The lower jaw of the mammoth excavated at West Runton, 1992-1995, showing the two teeth.When we think of creatures of the ice ages, it's probably mammoths with their tusks and big cats with two ferocious front teeth that come to mind. Fossils of both were found on the Norfolk coast by Alfred Savin and his fellow collectors. John Gunn came to Cromer in the 1870s to find where the teeth of a mammoth had been found when the Gangway was built; in the 1990s, an almost complete mammoth was found and excavated at West Runton. We can be sure that there are hundreds more fossils of mammoths in the Ice Age deposits of north Norfolk.
Mammoth or Elephant?
Mammoths and the elephants of today are in the same biological family. While today elephants are found only in Africa and south-east Asia, we can think of the mammoth as the elephant of the northern hemisphere. The mammoth story goes back five or six million years; they were flourishing until 20,000 years ago and became extinct about 4,000 years ago. Some of our knowledge comes from the many cave drawings of them by humans.
An upper second molar tooth of Mammuthus meridionalis, the ancestral ('southern') mammoth, in the Savin collection at the Natural History Museum, showing the partial evolution of the enamel ridges.
Another source of much of our knowledge on how they evolved is found from studying their teeth. The collecting undertaken by Alfred Savin and his fellow collectors played an important role that later would enable scientists to understand how mammoths moved from eating forest foods such as leaves, bark, and fruits to tougher grasses and grittier foods.
The mammoths of north Norfolk were not the woolly mammoths of the later, colder episodes. The local weather was much as it is today and a visit to Upton Fen in the Broads National Park will give an idea of the landscape in which the Norfolk mammoths lived.
Teeth for Grinding
As they developed from eating the forest foods to the grasses, mammoths' molar teeth developed an increasing number of enamel ridges that ground past each other and made it possible to eat the coarser food, including grasses. Examples of the earlier Mammuthus rumanus have fewer and broader ridges and by the time of Mammuthus primigenius, the woolly mammoth adapted to the iciest of climes, there are multiple ridges. In between those times are Mammuthus meridionalis and Mammuthus trogontherii, the examples found most commonly by Savin and fellow collectors.
An upper second molar tooth of Mammuthus trogontherii, in the Savin collection at the Natural History Museum, with the further development of the enamel ridges.
Wearing Down the Teeth
Another particular feature of mammoth teeth fossils is how tall they are – the scientific word is hypsodont. Their teeth evolved to be extra deep so they would last longer while wearing from eating abrasive vegetation. The teeth were also renewed, like today's elephants; there was one tooth for each jaw, four in action for chewing at any one time. Through their lifetime, mammoths like modern elephants had six sets of teeth, moving forward from the back of their jaw, pushing out the worn ones.
The tusks of mammoths are modified incisor teeth from the upper jaw. Their main function was as weapons but they probably also served for clearing grass and uprooting roots for food.
Our Understanding of Mammoths
Of all the extinct species, mammoths are probably the best understood. Because our ancestors saw them alive and drew them, right through to our recent ability to analyse their DNA, we have a very good understanding of them. The discovery in Siberia of the woolly mammoth known as Lyuba even provides information on skin and colouring.
