An inquest has heard how a polar bear which mauled a 17-year-old schoolboy to death was elderly and had been suffering from worn-down teeth which would have led to it becoming stressed and behaving more "aggressively and unpredictably".
Horatio Chapple was was sleeping in his tent on holiday in the Svalbard islands in August 2011 when he was killed as the bear went on the rampage, inflicting fatal injuries.
Assistant coroner Ian Singleton said: "[The bear] had badly aligned teeth causing them to wear down more than normal.
"It's probable it affected the bear's ability to gain food and if the bear is in pain it would have increased levels of stress causing it to behave more aggressively and unpredictably than it would otherwise."
A survivor of a deadly polar bear attack on a schools expedition in Norway has told an inquest he felt safe in the camp before the creature mauled him and his fellow explorers.
Patrick Flinders said the group received training on the use of trip wires on a briefing weekend before the trip with the British Schools Exploring Society "and a couple of days when we were out there".
However, he told the hearing he wasn't involved in the setting up of the system and said he also never had a discussion about a bear watch.
Mr Flinders says he also did some practice shooting with a rifle - shooting four rounds.
A boy who was hurt by a polar bear that killed a fellow teenager has told an inquest that he "saw the bear dragging someone out by his head" when it attacked his group's camp.
Patrick Flinders said he heard "rustling on the tent" when the attack took place in Svalbard, Norway - adding that he "thought people were just messing around from another group [...] until the tent collapsed."
He said he thought the attack he saw was on one of the expedition's leaders, but didn't see the bear attack anyone else, including 17-year-old Horatio Chapple, who died from his injuries.
He added: "Once the tent collapsed i got into a little ball and moved over to [Scott Bennell-Smith, fellow young explorer on the trip]"
The leader of the expedition on which a boy was killed by a polar bear has told an inquest the group had been supplied with an incomplete tripwire system.
The missing materials meant they had to set it up in a triangle formation rather than the advised rectangular shape, 31-year-old Michael Reid said.
He explained that his group also had to improvise using a paper clip to modify the trigger system because the brass fittings were missing.
He said: "The tripwire system in base camp worked inconsistently, the system that we tested at the ice-climbing camp on our first or second night out from the base camp operated 100% when we tested it."
The leader of a schools expedition on which a boy was killed by a polar bear has told an inquest a bear watch was not held on the night of the attack because it would have left the team tired and vulnerable to cold-related illness the next day.
Michael Reid, known as Spike, told the hearing into the death of 17-year-old Horatio Chapple that he wrestled the bear after a rifle failed to fire.
It was then shot dead with a second rifle, by which point lethal blows had been administered to the Eton pupil's head and upper body.
The boy's parents said they examined a risk assessment document with Horatio before he left - adding they "would not have let him go" on the Arctic expedition without believing he would be properly protected.
However, the inquest heard that there was in fact a shortage of trip wires, mines and pen flares available to the young explorers, while Reid told the inquest that his rifle failed to fire upon the attack.
Mr Chapple said the risk assessment also suggested that a bear watch would take place at the camp.