Adaptable and Resilient: Svalbard’s Deer Survive Despite Challenges in Winter and Genetic Adaptations Over Time

The small-sized deer of the Svalbards struggle in winter due to the lack of better moss, resulting in a loss of about a quarter of their weight. Despite facing challenges, the deer population on these islands has adapted well over time.

After migrating to populate the islands following the ice age, the initial herd of deer faced genetic bottlenecks due to mating between close relatives. This led to a genetic bottleneck that helped eliminate harmful gene variants from the population. In fact, Svalbard’s deer have fewer harmful gene variants compared to other northern deer populations in Russia, Norway, Greenland, and Canada.

While humans wisely avoid having children with close relatives to prevent genetic defects, this was not possible for the initial deer population on Svalbard. Over time, frequent mating between close relatives led to elimination of harmful gene defects as those affected became too ill to reproduce. This phenomenon is also observed in other species like the Indian tiger and New Zealand kakapo.

However, while researchers are relieved that Svalbard’s deer have fewer harmful gene variants than others, they fear that their luck may change due to current warming trends. Having adapted to arctic conditions during their bottleneck period, the deer may struggle to adapt quickly enough to a warming climate. This could pose challenges for their population in the near future.