National Geographic has just posted an exclusive video shot mid-summer of 2015 of a male polar bear killing and eating a young cub.
It’s worth watching (23 February 2016; “Polar bear cannialzies cub“) [update: Youtube version posted below]. It was filmed in 2015 in Baffin Bay at mid-summer (during either their July 28-Aug 9 or Aug 7- 19 cruise; pdf of itinerary, dates and prices – oh my god, the prices! here). [Summer is 1 July-30 September]
You’ll soon realize the male bear was not thin or starving (as was true of a much-publicized 2011 event captured on film off Svalbard).
It is also obvious based on the dates listed above that this incident debunks the explanation that cannibalism by adult males is driven primarily by their desire to mate with the mother of the consumed cub: this incident occurred sometime between August 7 and August 19 (as I was informed via email, by a reader on one of those two cruises), which is well past the breeding season for polar bears. A male bear would not still have viable sperm by August and a female could not be forced into estrus. [added 26 February 2016]
National Geographic is already hyping this incident as more evidence of climate change harming polar bears, as the article accompanying the video suggests. However, this is just the typical oversell that accompanies much to do with polar bear these days.
The bear was not “driven to desperation” : he simply took advantage of a rare chance to eat during the summer:
“Without the ability to hunt seals, polar bears may be driven to ever more extreme cannibalism, if they’re not already.”
It’s clear to me that this was an opportunistic kill made at a time of year when few seals are available, as even Stirling admits. It reiterates the point I’ve made many times before, that polar bears on the sea ice in summer have few feeding opportunities.
Incidents of cannibalism cannot be said to be increasing because there is no scientific baseline for which recent occurrences can be compared. Scattered anecdotal reports of any behaviour cannot be touted as evidence for a trend even though they may be of interest and worth recording.
UPDATE 23 February 2016: Video now posted on Youtube, see it copied below: