Brown bears love rubbing their backs on trees, and a recent study shows that bears who rub more trees than their trees are seen as more attractive to the opposite sex.
Scientists at the University of Alberta analyzed genomes of 213 individual brown bears in the Alberta Rocky Mountains and compared them to earlier DNA data to create a family tree.
They found that brown bears not only rub their backs on trees because the team found bears have hundreds of sites that they rub themselves against, such as poles and posts.
Researchers said that the rubbing behavior of brown bears could have a fitness component that makes them look more attractive to the opposite sex.
Bears Rubbing Their Backs on Trees
Live Science reported that grizzly bears rub their backs on trees to communicate with each other and not just trying to scratch an unbearable itch.
Some researchers in the past theorized that female bears might be rubbing their backs on trees when they are most fertile, while other researchers believe that this behavior is for bears to have a good scratch and cover the with sap as an insect repellant.
While ecologist Owen Nevin of the University of Cumbria said that bears, specifically males, have rubbed trees for generations to mark trees as they go look for their female mate.
Males usually become violent as they fight for a chance to mate. So when they smell other bear's scent on the tree, they know that they are in for a fight. Similarly, they also get aggressive to cubs of females and try to kill them to mate with the mother.
Cubs have been observed to rub against trees to acquire the scent of males because they tend to be less aggressive to their relatives.
Bears Rubbing on More Trees Have More Cubs
University of Alberta scientists described in their study, "The smell of success: Reproductive success related to rub behavior in brown bears" published in PLOS One, showed how both male and female grizzly bears have more mates and offspring when they rub on more trees.
The team also observed that females with more mates rub at more objects and on more occasions than those females who have fewer mates.
The Daily Mail reported that for every additional rub object and occasion during a female bear was detected, the chances of having more cubs is increased by 1.42 and 1.55 times respectively.
"It seems bears that are in good condition are more vigorous and they rub more, and that could be correlated with reproductive success," co-author Mark Boyce said.
Female Bears With Cubs Avoid Territories of Male Bears
Male bears tend to be too aggressive at times that they even kill cubs, which is why those female bears with cubs avoid their territories and often choose marginal habitat near ranch buildings or closer to roads.
They know that big male bears would not go near a building, but it is a risk that the females are willing to accept to escape the aggressive males.
The study also showed that male bears would fight for their territories and that includes their mates. They could sometimes have up to four females as their mates.
But females have a say in who they want to father their cubs. The study also showed that they choose the males based on the information they gathered from the scent of trees where male bears rub.
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