A stable isotope is one that does not change or decay radioactively. The proportions of these isotopes (nitrogen, hydrogen, oxygen, carbon) in plants, water, animal and air are determined by various environmental factors. So, by analysing these proportions, scientists are able to determine these different factors and how these specific ecosystems work.
For example, a tail hair that displays a low carbon-13-to-carbon-12 ratio is indicative of the elephant's eating trees and shrubs while that hair was growing (as opposed to grasses and crops). Similarly, if the elephant has a high ration of nitrogen-15-to-nitrogen-14, it would show that the elephant has spent their time in more arid plains. In lush periods of vegetative growth, elephants will feed off grass. In drier periods, they will resort to trees and shrubs.
Diet is essential, particularly to elephant bulls, who trek vast distances to find a receptive female with whom to mate. When food is short or inappropriate to the nutritional needs of the animal, his life is in danger and, with it, the strength of his potential herd.
While this exciting new method of tracking looks positive, it is recommended that it be partnered with another tracking method, such as satellite tracking, in order to support the findings. This method offers scientists a greater volume of information regarding the movements and motivations of these insightful animals. This then prompts them to make informed, realistic decisions about their conservation and care.