To figure out what grizzly bears have been eating over a course of several months, scientists have developed a technique that could provide the answer — just by analyzing a single strand of hair.
In a study published in the journal Science of the Total Environment, researchers elaborated that the technique can also be used to check how much mercury a bear is ingesting. Last year, a study was released determining that two out of three grizzly bears sampled in the coastal areas of British Columbia registered mercury levels beyond the neurochemical effect threshold recommended for polar bears.
Charles Robbins, an author for the study and director of Washington State University's Bear Research, Education and Conservation Center, said that it was easy to establish that bears eat salmon. After all, bears can be readily observed chasing down the fish. However, this knowledge doesn't provide a complete picture of what a bear's diet is like. Instead, the researchers are looking for something more specific — like knowing the "where" and "how much" of the protein and energy in a bear's diet.
Understanding what bears are eating will help bear researchers introduce the necessary changes in their habitats to ensure the bears get what they need to reproduce. Grizzly bears are categorized as threatened, according to the Endangered Species Act, so ensuring that they are well cared for is very important.
A bear's hair grows throughout its active season, and as hair is mostly composed of protein, it's a good (and readily available) indicator of how bears are getting their protein. The technique the researchers developed focuses on analyzing trace elements bound to sulfur atoms within keratin, the fibrous protein in hair.
This isn't the first time that hairs have been used as an assessment tool, but it is groundbreaking as just one piece of hair is necessary. Before, hair had to be analyzed in bulk or segment by segment.
To analyze bear hairs, researchers use a laser, running it down the length of a strand. As the hair is vaporized, gases are released and are then analyzed by a mass spectrometer. The technique is still in its infancy, but the researchers are confident that it can be developed for a number of applications.
Other authors for the study include Marie Noel, Jody Spence and Jennie Christensen.
Photo: Tim Evanson | Flickr
