The polar bear that mauled Eton schoolboy Horatio Chapple to death was old and suffering from tooth ache which made it more "aggressive and unpredictable," a coroner said.
The teenager, from Salisbury, Wiltshire, was sleeping in his tent when the bear went on the rampage, inflicting fatal injuries to his head and upper body.
Four others were hurt before the bear was shot dead at the Chanzin Fire campsite in the Svalbard islands, Norway on August 5, 2011.
Coroner Ian Singleton said the bear was able to enter the camp at around 7.30am undetected as the tripwire system, which worked "inconsistently" and had parts missing, failed to activate.
He added: "At the time of the attack the polar bear was 24 years of age, hungry and in pain from bad teeth, which more likely than not made it more aggressive and unpredictable."
More top news
Travel industry chiefs have called for universal safety standards to be introduced across Europe, to help prevent future tragedies.
The tragic deaths of two children on a Thomas Cook Corfu holiday in 2006 could lead to a crisis of confidence for the travel industry.
Sunny spells for tomorrow, although the further we go into the weekend then we will see outbreaks of rain moving south eastwards