Knut the polar bear died of autoimmune illness usually found in humans

Knut died suddenly at Berlin zoo in 2011, but the cause of the illness was a mystery until a researcher noticed similar symptoms in human patients

When a four-year-old celebrity polar bear named Knut died suddenly at Berlin zoo in 2011, vets were at a loss to explain the death.

Knut rose to fame as bear cub when he was rejected by his mother at birth, along with his twin brother who died within days.