What is the effect of reduced sea ice on polar bears?
The Arctic’s top predator, the polar bear, is affected both by the reduction in sea ice and by reduced stocks of its primary food, the ringed seal. Polar bears use sea ice as a platform for hunting their prey and for resting. They catch adult seals when they come up through the holes in the sea ice and search out the snow-covered ice caves of seal pups. But sea ice is decreasing throughout their Arctic range due to climate change. Ice reduction decreases the abundance of seals, and increases the amount of energy and time needed for hunting, leaving less energy for reproduction. Rising temperatures mean that large areas of the ocean that were once frozen throughout the year now become open water. Polar bears often have to swim long distances between areas of stable ice. As sea ice becomes thinner and multi-year ice disappears, a greater proportion of females make their dens on land, expending more energy to get there. Decreases in the physical condition of females and in reproduction ha
