The results of an extensive study on bear cubs and their mothers suggest that human hunting, and how it has been more strictly regulated in recent years, has played an important role in influencing how mother bears raise their young.
Typically, adult female Scandinavian brown bears spend only an average of 1.5 years with their cubs, according to Norwegian University of Life Sciences professor Jon Swenson. It was rare in the past, he added, that mother bears and their cubs would travel in the same group for 2.5 years. But, as Phys.org noted, cubs are more likely to stay with their mothers for about a year longer than they did about 15 to 20 years ago, with Swenson stressing that people are “now an evolutionary force” influencing the behavior of bears, including the Scandinavian brown bear, which Norwegian and Swedish scientists have been keeping track of for more than three decades.
All in all, Swenson and his colleagues have followed more than 500 Scandinavian brown bears since 1984, putting his team’s research among the two longest-running bear studies in existence. As the study progressed, Swedish hunters shot down more bears, with the five-year average from 2010 to 2014 being somewhere around 300 a year. However, the research offered an unusual takeaway, that mother bears don’t necessarily change the way they act to keep their cubs from being shot, and possibly killed, by human hunters.
According to the researchers, local hunting laws in countries where bear hunting is legal might be responsible for bear cubs being attached to their mothers for a longer period of time. These laws include those that prohibit hunters from killing bear families, which invariably result in a disproportionate amount of single bears killed, as opposed to those with cubs.
“A single female in Sweden is four times more likely to be shot as one with a cub,” said Swenson.
According to the findings of the study, which was published this week in the journal Nature Communications, the percentage of female Scandinavian brown bears who keep their cubs for 2.5 years instead of the usual 1.5 years has increased dramatically between 2005 and 2015, from 7 percent to 36 percent. There were no changes in individual behaviors observed in the mother bears, as their traits appeared to be “fixed” regardless of human hunting trends. Unfortunately, the researchers noted that this has also resulted in hunters focusing more on female bears who only stay with their cubs for about a year or so.
The growing tendency of Scandinavian brown bears to keep their cubs for an extra year might have a mixed impact on bear populations in other ways. According to SlashGear, mother bears who care for their young for longer tend to give birth to fewer cubs, though it’s also possible that this trend could be offset by these bears living longer than they normally would.