Tuskology, the Study of Mammoth Tusks
A Dendrochronological Approach to Studying Extinct Mammoths
Feb 11, 2009
Dendrochronology is a study that uses the rings of trees to tell of environmental factors present in a given tree’s life. Characteristics of the rings reveal intake of water and nutrients at certain times, designating environmental phenomena such as rainfall levels, floods, erosion, and soil composition historically present in a particular area. Rings in the tusks of mammoths do virtually the same thing: reveal the animal's nutritional condition and diet, which help to explain why mammoths fared as they did in a given location.
Tuskology
Adult mammoth tusks generally reached a length of about ten feet, and a width of around six inches at the base. The study of their tusks, deemed “tuskology,” reveals far more about the lives of individual mammoths than can be guessed by studying their closest relatives, Asian and African elephants. Cores (cylindrical samples perpendicular to the length of the tusk) are taken by boring out a section of tusk which contains a line where each ring passes through that section of tusk, and tests can be performed on the rings of the core, which are relative to the animal’s age at the time the ring was formed.
Chemicals found in the rings of tusks reveal the aspects of the subject's diet and therefore may describe what edible vegetation was present in the region. The rings determine if a given mammoth was malnourished, and in examining multiple mammoths of a given area, scientists may come to conclusions regarding the status of the species in the region where the remains where found.
Tuskological Application
Adam Rountree, a graduate student studying geology at the University of Michigan, and his adviser Daniel Fisher have been determining the ages at which juvenile mammoths become independent of their mothers, and high nitrogen levels in the inner rings of their tusks indicate young mammoths’ consumption of milk. The age at which a given mammoth weaned is most likely determinate of the environmental conditions that it experienced. During harsh winters, a mammoth would have sustained itself on its mother’s breast milk even as it was nearing six years of age, and nitrogen in the tusks pinpoint such times in a young mammoth’s life. As modern elephants feed on their mothers’ milk until nearly age six during times when food is scarce, multiple young mammoths having done this at any given location portrays the surroundings as unforgiving and void of adequate vegetation, which may help to explain the decline of mammoths in the area.
Physical Features of Tusks
Much like lightening scars on trees, physical features of a tusk explain physical moments that occurred in a mammoth’s life. When an indentation or ridge in a mammoth’s tusk near its base is found (generally in males), it signifies that the tusk had been jolted back into the socket as the animal had rammed something earlier, and as the mammoth grew, its tusk protruded further and the scar on the tusk moved out from the socket. Not surprisingly, a common cause of death in male mammoths was a shattered upper jaw (terminating the animal’s ability to chew), which resulted from a solid hit from a rival’s tusk, confirming the assumption that mammoths sparred during mating season.
The Purpose of Tuskology
Although our knowledge of these animals is still very limited, dendrochronological approaches on mammoths’ tusks (tuskological practices) are beginning to reveal more and more about the lives and surroundings of the animals, and these studies may eventually lead to a better understanding of this ancient elephant’s recent extinction.
