Hormones, Courtship and Hairy Legs!

Hormones. The body's chemical messengers that through the blood stream to our organs, muscles and other tissues. They control our growth, metabolism, reproduction, sleep cycles and many other bodily functions. But why are we telling you this? It's because polar bears are no different!

Throughout the year (not to mention as they age), a polar bear's hormones rise and fall, and as a result, their wants, needs, preferences and overall behaviour also changes. One of the key hormones in the control of a male bears' behaviour is called testosterone. Testosterone is an extremely important hormone for male polar bears, as it promotes courtship and reproductive behaviour, as well as sperm production and secondary sexual trait production (think of the very long hairs on the back of Inukshuk's forelegs). For a species that is largely solitary in the wild, testosterone is what drives male polar bears to search over thousands of square kilometers to find females to breed with, helping to ensure the next generation of this threatened species. Testosterone begins to peak in early spring, when the days are getting longer and the ice platforms are still strong. This peak, also known as the 'breeding season' will last right through until the late summer, and in that time, a male will breed with as many females as he can. The testosterone coursing through his body will suppress his appetite, even causing him to leave behind a fresh seal kill if he catches the scent of a female. Once he finds a female, he will breed with her over the following couple of weeks, until the time when she loses interest and no longer participates in courtship behaviours. To ensure his genes are successful in being passed onto the next generation, he will guard the female from other competing males. Male polar bears can weigh up to 1500lbs, therefore body posturing between males will come first. If that doesn't get the message across, intense physical altercations will occur. The winning male will be the largest, strongest bear, meaning that the largest, strongest genes will be passed on.

Inukshuk's beautiful leg hairs let females know that he has strong male genes. In other words, he is very attractive!

As the warm summer days pass by, testosterone levels will begin to fall and with it, their interest in searching for and mating with females. A male polar bear's food drive will increase quite rapidly, urging him to gain as much weight as possible before the sea ice melts and retreats north, which makes hunting for seals almost impossible. In the fall, when their testosterone levels are at their lowest, male polar bears become quite social and can be seen congregating close to the coast, while they wait for the sea ice to freeze up once again. Small groups of males can be seen wrestling, sparring and sleeping together; a distinct difference from the breeding season when they are entirely solitary. Once the sea ice reforms, they will separate and go about hunting and travelling in preparation for another year's breeding season.

Now that we have spoken about testosterone in wild bears, what does that mean for bears in human care like Ganuk, Henry and Inukshuk? Well, to put it bluntly, it means exactly the same thing. We begin to see a change in their behaviour in mid-February, with Henry becoming more vocal when Ganuk is not in sight, Inukshuk staying close by to Henry, and Ganuk showing more interest in Inukshuk. As the testosterone rises, this increased interest in one another becomes stronger, and the Animal Care Team will alter their daily management of the bears to suit their change in needs. Working with only polar bears means that our team is able to predict and act preemptively, resulting in a smoother transition into what can be a very challenging time of year. As we do not house female polar bears, our males' natural drive to search for and court a female is directed toward each other. Unfortunately, they are not receptive to each other's advancements and aggression is much more likely. To ensure their safety, the bears are housed separately, but always in a way that allows them to see one another, which has proven to greatly reduce stress and foster a calm environment. As with wild bears, their interest in food drops substantially, and they will often ignore offers of food in favour of sitting and watching one another. These behaviours will continue through the spring and into the summer. Then, almost like a switch has been flipped, they will begin to show more independence. Henry, especially, will shift his interest from Ganuk onto the Animal Care Team, who will be increasing his diet as his appetite quickly grows. By the end of July or beginning of August, Henry and Inukshuk will show interest in being housed together again, and Ganuk will choose to spend his time napping in big beds made of straw. When the weather really begins to cool in October, sparring and wrestling behaviours between Henry and Inukshuk become a daily occurrence, whereas Ganuk will show interest 'playing' with the Animal Care Team through the fence. Once again, the Team will have to completely change their management of the bears, to keep up with their change in needs.

Inukshuk (left) and Henry (right) enjoying time together in the winter. Photo credit: Austin McIntosh

When you are planning your visit to The Habitat, we encourage you to think about how their behaviours change throughout the year and how this could affect your experience. While our Animal Care Team is always here to provide a rich, educational experience, the likelihood of seeing the bears acting in certain ways varies greatly with their hormonal changes. In the spring and summer months, there may be a higher chance of seeing them swim, but when they are not swimming, they may sometimes remain out of sight for long periods of time if they have settled into watching one another. If you would like to see them interacting and eating more frequently, the fall and winter are the best times to visit. Although it may be colder for us, this is prime polar bear viewing time.

Ganuk taking a stroll in the snow. Photo credit: Austin McIntosh

As always, we are here for our bears and to meet their needs, not the needs of people. The Polar Bear Habitat is a unique place to learn about and understand polar bears, where lasting memories are made, and opportunities to view bears in a sub-arctic environment are possible. If you visit and don't see a bear, just remember that it is because they are being given the choice and control to act as they wish, allowing them the best possible standards of welfare and care.