Scientists are using thermal imagery to better understand how polar bears regulate their body temperature. New, non-invasive study methods like these can help answer questions about polar bears, their health, and the impacts of climate change. Image courtesy of Daniel Gibson.

1/25/2016 2:45:50 PM

Polar Bears in a Different Light

Working as a scientist at the Churchill Northern Studies Centre while also interning at the Assiniboine Park Zoo has afforded me the opportunity to interact with and observe both wild and captive polar bears and gain valuable information about the bears and their behaviors.

Just as other wildlife biologists always try to improve their methods, our team is looking into new methods of studying bears. Field biology has been moving towards using non-invasive techniques to collect animal data, especially for large mammals and species of conservation concern.

We're interested in how polar bears regulate their body temperature. Climate can influence the overall health and body condition of polar bears on both an individual and population level. As the climate changes, we expect warmer temperatures in the Arctic to affect polar bears on many levels, such as increased difficulty in catching seals due to a longer ice-free season. Further, increasing temperatures may cause thermal stress. For example, polar bears in Churchill must endure warm summer temperatures up to 30°C; how do they stay cool and not overheat? Additionally, for captive bears in the South, how do they stay cool when the temperature is far out of their comfort zone?

Our team is trying to better understand which behaviors contribute to a bear's ability to stay cool in the summer or keep warm in the winter. We are using infrared thermography to non-invasively measure body temperature while simultaneously documenting polar bear behaviors to determine how they may affect body temperature.

Thermography techniques have been used to study polar bears in the past; however, the general conclusion was that the bears are almost too well insulated to measure their body temperature accurately. As thermography technology has continued to improve, though, the use of this technique has become more affordable, and the increased resolution now allows for more precise questions to be answered.

Our first mission was to establish an accurate method to determine a polar bear's core temperature. Thermography has been used successfully in horses to diagnose fever using the eye temperature. Based on the thermal videos of the polar bears at the Assiniboine Park Zoo and in the wild, it appears the eye temperature remains fairly constant, making eyes the perfect candidate for further study. If eyes can provide a window into the internal temperature of the bear, we could potentially use thermography to study how fast bears warm up or cool off after entering or exiting the water.   

Our preliminary results show that the eye temperature is consistently a few degrees cooler than expected body temperature (from literature) and with quick mathematical calculations, we can accurately estimate the internal temperature of the bear.

Using non-invasive methods such as thermography to study polar bears will provide us with a more cost-effective and safer option to answer questions about polar bears, their health, and how climate change may be affecting both individuals and populations as a whole.

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