Polar bear expert: 'An incredibly curious species'

A polar bear has mauled a 17-year-old British boy to death in the Arctic and left four other UK tourists badly hurt.

A party of 80 mainly 16 to 23-year-olds were on a trip with the British Schools Exploring Society (BSES) near a glacier on the remote Norwegian island of Svalbard.

Polar bear expert Douglas Richardson explained to BBC News the reasons why a polar bear might initiate an encounter with humans.