Beside camping too close to the bear's prowling grounds, most likely, there was some food or smelly gas in the tent. The curious polar bear like all other bear species was attracted by the smell, went to investigate and started to pull the middle one of the three bodies out from the tent. After all, from a bear perspective, anything putrid inside a heavy sleeping bag resembles a seal. When surprised by the squirming body in the sleeping bag, his natural reaction was the "attack".
Bears have 7 times more powerful sense of smell than a dog and can detect an aromatic Prague Sausage over a mile away.
Most bear encounters are caused by surprising a bear and usually can be prevented. Understanding bear behavior and recognizing bear sign are important and basic safety rules should be mandatory when hiking or camping in bear country (applies to black, brown, and white bears).
http://www.env.gov.bc.ca/bcparks/explore/misc/bears/bearsaf.htmlEDIT:
With over 2,000 tourists as reported currently in this area, such accidents are bound to happen.
The polar bear that in 2011 killed in the same area (outside of Longyearbyen) a young Brit, injured four other people, two of them more seriously than Moravec in this year's attack. As mentioned by Slobodan above, three bears are killed every year in this area in "self-defense". This compares with 15 deaths of grizzly bears in Alberta last year, that were struck by vehicles on highways, shot in self-defence or killed illegally. The current grizzly population in entire province of Alberta is estimated at only about 700, so the relative
killing of grizzlies there is twenty times more alarming that of polar bears.
According to the local law, all tourists outside of the settlements in Spitsbergen should be accompanied by a local armed guide. The group of six Czechs went on their own and although they strung a bear alarm fence around their tents, the relatively small bear managed to squeeze under the fence without triggering the fireworks. Similarly, the group in 2001 bear attack installed also a wire alarm fence around their camping area, which failed as well. Either poor quality alarm fences, or insufficient knowledge in setting it up.
The shots from the pistol fired by a woman in the next tent scared the bear who ran away but the inflicted injuries were serious enough for bear's survival and it had to be killed by the local police. After being treated in the hospital, Moravec said that he feels fine, is looking forward to shoot the solar eclipse and would enjoy returning to that area in the future.
