Cannibalism: Is climate change causing polar bears to eat each other?

Polar bears were listed as “threatened” under the Endangered Species Act (ESA) in 2008, following a petition by environmental groups. The decision was upheld in the D.C. Circuit Court early in 2013, after a challenge by the State of Alaska, sport hunters and other special interest groups. The polar bear listing represented the first animal placed under ESA protection solely as a result of climate change, which is the cause of melting Arctic sea ice where polar bears live and hunt for food. Cannibalism and infanticide is one of the dark sides of nature and it is not uncommon in many species, but scientists report an increase in polar bears feasting on cubs and females in recent years. Stories of such gruesome activities go back to the late 1800s, but challengers say there are more sightings now due to increased accessibility by researchers with cameras. Recent disturbing eyewitness accounts reported by Discovery Channel told of males taking cubs and attacking females in their dens. One scientist says polar bears, the largest of the bear species, do it “just because they can.” Dr. Susan J. Crockford is a zoologist, who claims polar bears kill each other for a number of reasons. Excerpt from her website: “Male bears kill newborn cubs in the spring to bring females into estrus – so that they are able and willing to mate again with the new male (this only works until perhaps early June at the latest); 2) females may eat their young (probably at any time of year) when they can’t get other food; 3) males will kill adult females, smaller bears and cubs at any time of year and eat them – whether they are thin or fat, truly hungry or not – just because they can.”Nonetheless, other researchers believe starvation is driving polar bears to turn on their own as food becomes less reachable due to melting ice. Dr. Ian Stirling of Environment Canada has been studying polar bears for more than 40 years and he believes early ice melts are the cause of more cannibalism reports. Ice floes melt in summer, with many disappearing totally, making hunting for the bear’s favorite food of seals more difficult, which forces them to roam further and settle for less; like sea birds and their eggs...more