CHICAGO (AFP) - An African lioness who gained worldwide fame for developing a mane similar to male lions has died, the Oklahoma City Zoo announced on Thursday (April 5).
Only young male lions typically grow manes when they are about one year old. But 18-year-old Bridget suddenly grew a modest mane last year, initially puzzling zookeepers.
They announced the phenomenon in February - garnering international headlines - and a month later said they had solved the mystery.
After blood tests, they discovered that Bridget had what was believed to be a benign tumour on an adrenal gland that released excess amounts of hormones that led to the mane growth.
She had remained healthy and unbothered by her sudden change, the zoo reported.
Earlier this week, Bridget became lethargic and tests revealed excess fluid build-up around her heart, "indicative of heart failure or infection," the Oklahoma City Zoo said in a statement.
"Given her advanced age and the severity of her condition, the vet and caretaker teams made the difficult decision to humanely euthanise Bridget," the zoo said.
Bridget lived beyond the median life expectancy for African lions, which is 17 years, according to the zoo.
A necropsy was planned to determine the exact cause of death.
African lions are considered vulnerable, with only 20,000 left in the wild, according to the World Wildlife Fund.