(Image: Amanda Sorenson, showing Bridget before her mane growth and after)
An elderly lioness at a zoo in the US city of Oklahoma has baffled her caregivers by growing a mane.
Bridget, an 18-year-old animal who was born in captivity, grew the mane between March and November 2017.
Usually, manes develop in male lions when they are about a year old because of increased testosterone production. Lionesses don’t grow them.
Vets at Oklahoma City Zoo are working to discover what has caused Bridget’s unusual hair growth.
“Aside from a natural genetic component, another potential condition causing the mane growth could be a benign tumour located on her adrenal or pituitary gland as these regulate hormones like testosterone,” the zoo said in a blog post.
Caregivers have trained Bridget to allow them to draw blood from her tail to test – bypassing the need for anaesthesia, which they don’t want to perform because of her age. But Dr Jennifer D’Agostino, her vet, told US publication Newsweek they don’t have quite enough blood yet to confirm what the problem is.
Otherwise, they see no change in Bridget’s state of health and it appears her condition is not completely unheard of.
In 2011, a lioness in a zoo in South Africa grew a mane after an ovarian condition caused excess testosterone production.
Lionesses with manes have also been seen on at least two occasions in the wild. One involved a group of five related lionesses in Botswana and researchers believe a genetic factor in the grouping may have caused the condition.