A female zoo worker has died after being mauled by a tiger at South Lakes Wild Animal Park in Cumbria.
Sarah McClay, 24, was attacked by a Sumatran tiger at the zoo in Dalton-in-Furness.
Paramedics said she suffered "very traumatic injuries" to her head and neck and went into cardiac arrest. She was resuscitated and taken by air ambulance to the Royal Preston Hospital but died of her injuries.
Zoo owner David Gill told the BBC there was "no reason" for her to be in the enclosure.
He said she was a "very experienced" staff member who had worked with big cats, was "proficient and passionate" at her job, and had worked at the park for a number of years.
Mr Gill said: "We have very strict protocols and procedures for working with big cats, but it seems she failed to follow correct procedures.
"For inexplicable reasons she opened a door and walked into the enclosure.
"We will never know why she entered without telling anyone. There was no reason for her to go in there."
Mr Gill described Ms McClay as "a very bubbly character, a very happy girl" and described her death as a "tragedy for her family and all the staff".
Police said that Ms McClay's family was "very shocked and distressed".
The attack happened at 4pm BST, during the park's opening hours, and was witnessed by a member of the public.
After the attack, the park was closed early and visitors evacuated from the area, it re-opened as normal today.
Mr Gill said: "The public were not at risk and we followed all our accident procedures to the letter.
"We had a meeting of all staff at 5.30pm and asked what they wanted. There was a huge consensus of opinion that we carry on.
"It would not do any good to close the park as there is no safety issue."
He said the tiger had lived at the park for 10 years since it was a cub and would not be destroyed.
"He didn't do anything wrong. He's a tiger and his natural instinct is to kill. We all know that and that's why all the protocols are in place.
"He didn't make a mistake, he was just there. We don't blame him for what happened."
The attack is being investigated by Cumbria Police and Barrow Borough Council.