After spending the summer resting on the coast lines of James Bay and Hudson Bay, the polar bears are feeling a change. The days are beginning to get shorter, snow has started and the bears are beginning to get more active. In the summer and early fall, from early June right through to mid November, the bears of the Southern Hudson Bay population are forced onto land as the sea ice melts and retreats north. With the warmer temperatures and lack of access to their primary food source, seals, polar bears spend the majority of their time resting. A fasting polar bear loses approximately 1kg of weight per day, therefore remaining inactive is the best way to preserve energy stores until the ice returns. During the summer months, age and sex classes of bears are often found segregated. Mature males remain solitary and close to the coast where it is cooler, whereas females with cubs and sub adult males can be found further inland. Although not common, large males have been observed predating on small cubs so it is understandable why females keep a safe distance from males.
A female and her cubs, most likely yearlings, surveying the area. Photo credit: Manuel Menrath, taken near the town of Forth Severn on the Hudson Bay coast.
A solitary bear on the coast. Photo Credit: Manuel Menrath, taken near the town of Fort Severn on the Hudson Bay coast.
As fall wears on, males of all ages will begin to congregate closer to the coast. Older, larger males will remain solitary although activity levels of all bears will begin to increase. Young males engage in wrestling matches, also known as play fighting or sparring. This behaviour is an important part of a young bear’s development as it teaches them the skills they will need when fighting with other males over resources such as food or females. It has also been suggested this behaviour helps to re-strengthen their muscles after the summer period of inactivity.
Wrestling matches often begin with two males opening their mouths to one another, known as going mouth to mouth or mouthing. This will then evolve into both bears standing on their hind legs with their heads down, mouths open and front legs partially held up. Bears will push against one another’s neck and shoulders with the apparent aim of knocking the other over. If one bear does indeed get knocked over, the dominating bear will pin the other on the ground, biting the face and neck of the other bear. Although this behaviour can appear rough, with each bear capable of inflicting wounds to the other, they usually do not. This behaviour is all done in the name of play and often ends with one bear retreating with ease. Opponents are chosen based on size, with the winner of a tussle sometimes being challenged by another male onlooker. Energy expenditure from this type of interaction can be high therefore bouts are often only three to four minutes, although some last considerably longer.
Polar bears sparring. Photo credit: Explore.org
Join us tomorrow as we take a look at the behaviours shown at this time of year by the bears at The Cochrane Polar Bear Habitat.