Polar bears evolved from brown bears over 38 million years ago. Today there are around 19 known species of them around world.
We all know polar bears live only in Arctic region where they use sea ice as a platform to walk and hunt. Now imagine that platform dissolving in sea water. How are they going to survive?
Simple, they’ll adapt to land just like their brown cousins. Right?
The first problem is time. They took over 10,000 years to evolve from brown bears to big, white ice dwelling creatures we know today. Even if they do somehow “Re-adapt”, the pace would be too slow compared to the warming climate trend.
This brings us to second problem. Polar bears are highly specialized, both physically and physiologically, for a world of sea, ice, and meat: shorter, stockier claws to better grip prey and ice; smaller, more jagged molars and larger, sharper canines, better serving an almost exclusively carnivorous diet; all-white coats to provide camouflage while stalking prey; larger, thicker bodies to increase the ratio of surface area to body mass, helping the bears conserve energy and body heat; and a more elongated body, skull and nose to enhance streamlining and better enable the bears to thrust their heads through snow and ice into seal denning lairs and breathing holes.
These changing adaptations are affecting their reproduction system.
A female polar bear can give birth only once in every three years. And if the female bears are stressed regarding living environment or lack of food, they do not engage in reproducing at all. And at the top of that, 60% of the cubs do not survive more than a year due to changing climate. In 2001-2010, their population has decreased 40% from 1500 to 900. Today there are less than 25000 polar bears in the world.
Ultimately, whether polar bears can adapt to land may be irrelevant. Polar bears are defined by the sea ice ecosystem they inhabit. Without it, polar bears will cease being polar bears. Even if they could somehow manage to persist on land, they would quickly encounter and hybridize with their brown neighbors (as they have already begun to do), and the iconic, white sea bear we recognize so readily today would disappear. For all practical purposes, the species would be lost.
Fortunately, NRDC and others are working hard to prevent that from happening, by combating climate change, protecting polar bear habitat, and working with the international community to ban the global trade in polar bear parts. Through these efforts, we hope to curb rising temperatures, decelerate the loss of sea ice, and buy these emblematic bears as much time as we can.
Will polar bears adapt to land? Or they will just disappear in next 100 years? Let’s do everything we can to make sure we never have to find out.