Winter may appear to be the most dangerous season for a young animal. However, the next few weeks could mean the difference between life and death for Scandinavian brown bear cubs. Do you know how mama bears keep their cubs safe?
Mama bears are so protective of their cubs that they actively seek out human-occupied areas because they know male bears, who want to kill their cubs to increase the chances of a mate, will avoid human contact.
The Need for Mating Against All Odds
Martin Leclerc, a PhD student in biology at Quebec’s Université de Sherbrooke, was conducting field research as part of a more extensive study on how bears interact with humans. The anecdote is not from his thesis work, but it illustrates the type of behavior he studied. One unexpected finding from that study, published in the Proceedings of the Royal Society B, suggests that female bears with cubs may use humans as a shield to avoid infanticide.
As cities expand worldwide, many animals are devising novel ways to compensate for the loss of prime habitat due to human development. While we may see their presence as a breach in the imaginary line we’ve drawn between nature and civilization, the animals themselves make colder calculations based on survival and relative danger.
Male Eurasian brown bears approach family formation in a somewhat Machiavellian manner. During mating season, some males will kill the cubs of a female they encounter, knowing that she will become open to reproducing again in a few days.
The main reason they kill the cubs is to gain higher sexual opportunity.
Martin Leclerc, PhD Student in Biology at Quebec’s Université de Sherbrooke
(Source: The Smithsonian Magazine)
The Human Shield Against Male Bears
On the other hand, male bears are often wary of approaching human civilizations, which may provide an opportunity for females. From 2005 to 2012, Leclerc and his colleagues examined extreme cases in which all of a bear’s cubs survived or were killed because males intent on guerrilla family formation usually wipe out the entire litter if they can.
GPS data and spot-checking from the ground and helicopters to see if cubs survived the mating season revealed that the most successful mothers hung out more frequently and relatively close to humans. In contrast, those who avoided human infrastructure frequently lost cubs.
In a way it’s the best of two evils to go close to humans, In other words, humans may stress bears out, but for mother bears this danger is trumped by the fear of male bears in mating season. The moment that mating season is over and when the chance of her cubs being killed by a male is over, she instantly switches back to avoiding humans. It’s very much that she takes the opportunity of this time window when the humans are perceived as less threat than the males that come and victimize her.
Leif Egil Loe, Professor of Wildlife Biology at the Norwegian University of Life Sciences
(Source: The Smithsonian Magazine)
Image from Newsela