Field Journal: Tracking and Trapping a Bear

From the Field posts

Rae Wynn-Grant is a conservation science research and teaching postdoctoral fellow jointly appointed with the Center for Biodiversity and Conservation and the Museum's Education department. Her work explores the influence of human activity on large carnivore ecology. Dr. Wynn-Grant is currently studying the impacts of human activity on landscape use, habitat suitability, and habitat connectivity of black bears in Nevada, where she was conducting her research when she wrote this field journal last month.

We’ve trapped a bear! It took quite some time and a lot of patience, but when we checked one of our bear traps recently, it was occupied by a bear who had been exploring the area—which is near one of the popular ski resorts in the region—and apparently couldn’t pass up a free meal in one of our traps.

Bear Tooth Exam

While this male black bear is tranquilized, we check his teeth for signs of wear to help determine his age and health status.  

© R. Wynn-Grant


The caged bear was a cinnamon-furred male, about five years old and weighing around 250 pounds. Though this animal was cinnamon in color, it was still a black bear—many people don’t realize that as a species, black bears can display a variety of colors, including grey, brown, and even occasionally white. Despite the fact that he had just emerged from a long hibernation, this guy was in excellent physical condition. 

We tranquilized the bear, then carried him out of the trap in order to take measurements, collect hair and blood samples used in DNA analysis, and place an identification tag on his ear, as well as a GPS collar around his neck. These collars emit a signal that connects with a satellite, giving us a reading of the animal’s longitude and latitude every 3 hours. This information is stored in a database that helps in the development of habitat selection models. 

Bear Night Vision Camera Trap

The combination of GPS collars, ear tags, and camera traps help to track bear populations. 

© R. Wynn-Grant


GPS collars are especially useful during the winter months, because they can tell us where bears are making their winter dens, which is a priority for our research. We’re extremely interested in what type of habitat is preferred by black bears for dens, especially in terms of the proximity to human-dominated areas. We are also curious about what different bears look for in dens. Are there significant differences between the locations of dens for males and females? What about females with cubs? Having all of this information is important to creating effective models for managing human-bear relationships in the area and minimizing conflicts between the two species.

Also notable was the fact that this bear didn't have an ear tag, which means it had never been trapped before. This is always exciting because it means that we’re getting information from a brand new individual to add to our database. We’re all eager to see where this bear spends most of his time, and now we'll be able to track his movements throughout the year. 

To learn more about Dr. Wynn-Grant's work, you can read here first post from the field here and here.