Want to monitor bears? Try checking their saliva

Scientists may very well be drooling over a tasty bear monitoring method in Alaska, and the key ingredients are bear saliva and salmon.

The technique involves gleaning genetic information from salmon that brown bears have munched on, and researchers report that it works better, and is cheaper, than previous methods like using feces to identify the bears. Luckily for science, bears don’t always finish their salmon meals, and that means that the fish carcasses are a great place for scientists to get ursine DNA, according to a new study.

“When salmon are plentiful, bears rarely eat the entire fish. In some cases, they only eat the brain, and we’ve found that swabbing along the edges of the braincase gives us the best results for extracting DNA,” Rachel Wheat, first author on the new study, said in a statement. “We also had success with swabbing inside distinct bite holes, and in the muscle tissue where the bears have stripped the skin off the salmon.”


The researchers focused on two types of salmon, chum and sockeye, in two watersheds in southeast Alaska, and got their data from 156 fish bodies. As a comparison, they also took swabs from bear scats. It turns out that they were more likely to get genetic information from the fish carcasses than the bear feces: more than 50 percent of the fish provided bear DNA, compared to just 35 percent from the bear scat. The saliva method was also much cheaper, with the fish’s braincase providing better info than bite holes.

The technique is a “promising method” towards monitoring animals like bears, according to the study, which was published this month in the journal PLOS ONE.

“This advance will help allow us to more effectively – and more economically – study one of the largest bears on the planet,” Wheat said in the statement.

Follow Rob Verger on Twitter: @robverger