Polar Bear footprints used to develop ethical tracking techniques

Written by Science

Swedish scientists working with the WWF Alaska and the Department of Wildlife Management have been able to isolate DNA from left over cellular debris in snow pawprints of polar bears. This is the first time this has been attempted successfully and holds huge potential for understanding these majestic creatures.

Polar bears are significantly under pressure due to climate change. Ice in polar regions are melting much more quickly than first thought and is a huge threat to polar bears and the entire ecosystem that they are part of. This ecosystem is also important for humans as huge amounts of our fish come from these ecosystems. Understanding polar bear numbers and the genetics of the population can provide insight into how climate change is impacting these majestic creatures and what we can do to help them.

Currently, the main way that biological samples are taken from these animals is through sedation and then taking blood. This is extremely stressful for the polar bears and is also dangerous for the scientists who carry out the work. Taking DNA from the environment is a non-invasive and reliable way of collecting this important information.

Working closely with the local Inuit population, Iñupiats, the scientists were able to trace the polar bears and find their pawprints and take samples of snow. However, this had to be carried out at night when temperatures plummet to around -40 degrees because UV light from the sun degrades the eDNA (environmental DNA) in the pawprints. Although this work was successful, little DNA was left behind in each pawprint due to this extreme weather and over 40 samples had to be taken. This is difficult and tiring work but thankfully their hard work paid off when they were able to isolate and use this eDNA for polar bear population research.

The use of eDNA has been happening for a number of years with different organisms. It had mostly be carried out with aquatic organisms because of the ease of collecting their eDNA: through collecting water that these organisms live in. This has given insight into the structure of an ecosystem and evolutionary relationships between organisms. This work with polar bears will give accurate information about which species are in an environment and also their population size and behaviour.

Although this is early days for this new and fascinating technique, it holds huge potential for non-intrusive study of other animals. This work could play a substantial role in the future understanding of organisms and ecosystems.


Last modified: 13th May 2020

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