5/30/2014 4:28:34 AM
After a Long Day on the Ice
We've just returned to Polar Bear Cabin after a successful day of tagging polar bears in Viscount Melville Sound in the Canadian High Arctic. However, we still have much work to do before we can start cooking dinner on the propane stove and relaxing for the night, listening to the wind howling outside.
Our evening work consists of three main things:
• Cleaning and preparing the darts used today for sedating bears from the helicopter so we can use them again
• Labeling and sorting the polar bear tissue samples that we obtained
• Preparing new sample kits (with the necessary number of bags, vials, scalpels, etc.) for the bears we hope to tag and sample over the next days
Every time we have a sedated bear during these tagging trips, we take a number of biological samples from the animal. These samples are small, but help us answer a lot of the questions about the health and biology of the bears, furthering our understanding of these animals.
Each tissue sample can be used for a wide range of different analyses once we are back in the lab in Edmonton. For example, fat biopsies can tell us how polluted the bears are, and also what kind of prey they have been eating. Claw samples also give an indication of the bear's diet. Tooth samples reveal the age of the bear and—in case of female bears—tell us how often and at what age they have had cubs. Hair samples provide information on the bears' genetics and their hormone levels. Saliva likewise gives us DNA but also information on the bears' oral bacterial flora.
From time to time, we collect additional samples, too: for example, blood can tell us many different things about the bears' health, such as vitamin and hormone levels, and the existence of a range of diseases and infections. Small amounts of milk from nursing females help us learn about the composition of polar bear milk and let us study which pollutants, vitamins, etc., are transferred to the cubs from their moms.
Biological tissue samples such as these can obviously tell us a lot about the health and history of an individual bear. But even better: if all the bears that are tagged in the different areas of the Arctic are sampled consistently, these samples will provide insights on the health of the entire polar bear population. We will then be able to make a number of assessments:
• Whether some polar bear populations are more polluted than others, as well as the potential effects of the pollution
• Whether the age composition of the bears that are tagged have changed over the years
• Whether the polar bears' prey choice has changed over the years
• How often polar bears from the different areas mate with each other
In other words, the biological samples give us insights into the life and ecology of polar bears that we would otherwise never be able to obtain. These insights are vital to our understanding of the bears, their environment, and how best to manage and protect them.
So, as you can see, the amount of information we can get about polar bears from this small handful of tissue samples is substantial as well as important. This is why labeling and sorting them out takes precedence over making dinner, even after a long day out on the ice!