Rubbing their backs on trees, fence posts and even power poles does more than scratch an itch for grizzly bears. It’s a way for the big animals to leave behind their scent.
This is an important way for the animals to communicate. Scientists in Alberta, Canada, completed a recent study that also found the grizzlies making the most rubs had more cubs. Likewise, bears that rubbed more often also had more mates.
The scientists think the reason for this is that bears in better physical shape rub more often. The study also found these rubs helped females avoid larger males, which are known to kill cubs. By identifying where the big males were, females could move to places farther away to protect their babies.
To steer clear of the big males, females would choose areas closer to buildings and roads — places the males avoided.
Scientists used hair left on these rub sites to make their findings. By collecting the hairs, they could analyze them for DNA. DNA is a molecule that scientists can use to identify plants, animals and even bacteria. In other words, they could use the hair to identify specific bears. DNA can even tell them if the bears are related.
The scientists collected hair from 899 rub spots over four years. From the hairs they were able to identify 213 individual bears. They then used these results to create a family tree, showing which bears were related, by using DNA from another 2,043 bears in the area.
The use of bear and other animal hairs, such as wolverine, has been a huge help for scientists trying to estimate how many animals may be in an area, such as Glacier National Park.
Who knew your hair could reveal so much more about you than your hairstyle?
— Brett French, email@example.com