Past cycles of climate change, along with human exploitation, have led to only small and isolated stocks of Atlantic walrus remaining. The current population is at high risk of the same issues affecting them severely, according to a new study led by Lund University in Sweden.
Now, researchers have examined how walrus coped with past cycles of climate change. Using breakthroughs in ancient genomics, the team was able to extract, sequence and interpret ancient genetic information contained in teeth and bone that survive well in the Arctic's frozen archaeological sites. These DNA results were integrated with modern genetic samples, enabling them to reconstruct how the genetic diversity of Atlantic walrus had changed under earlier cycles of global warming.
In addition, during the last thousand years, human hunting and commercial exploitation has led to numerous local extinction events. These include the expansion of Norse settlers into Iceland and the North Atlantic in pursuit of walrus ivory, which was a valuable trade good, and in more recent times, with industrial scale culling of walrus populations.