Story transcript

Bridget the lioness has been rocking a dignified beard since 2017, much to the shock of her keepers at the Oklahoma City Zoo.

"She is in very good health for an 18-year-old girl," Jennifer D'Agostino, the zoo's director of veterinary medicine, told As It Happens host Carol Off.

"Doesn't even seem to be bothered she has a little bit of extra hair around her chin and her neck area."

The zoo is calling Bridget's new look a "mini-mane" and says she grew it between March and November of 2017.

Not the 1st

Male lions grow their manes at about one year of age as a result of testosterone production.

It's highly unusual for a female lion to grow one, but Bridget isn't the world's only bearded lioness.

"Since we've started talking with our colleagues, I definitely think it could be more common than what we realize," D'Agostino said.

Bridget is an 18-year-old lioness who has baffled her handlers at the Oklahoma City Zoo by suddenly growing a small lion's mane. (Sabrina Heise/Oklahoma City Zoo)

Emma, a 13-year-old captive lioness at the National Zoological Gardens of South Africa, sprouted a short mane on her neck and head in 2013.

In 2016, five wild lionesses at the Moremi Game Reserve in Botswana grew big, lush manes and started to behave aggressively like males.

One of them even started mounting other lionesses.

No other changes

But Bridget doesn't seem to be acting any differently now than she did pre-mane, D'Agostino said.

Nor are the other lions in her pride treating her any differently.

"Everyone has been sort of business as usual every day and they don't seem to notice it," she said.

Bridget, right, hangs out at the Oklahoma City Zoo with lioness Tia, left, and lion Hubert, centre. The other lions are unbothered by her beard, staff say. (Gillian Lang/Oklahoma City Zoo )

In Emma's case, scientists found her ovaries were producing excess testosterone. In Botswana, scientists suspect a genetic connection between the maned lionesses.

As for Bridget, the veterinarians are still trying to figure it out. But they have a couple theories.

Linked to her age?

D'Agostino suspects it could be related to her age.

"Maybe this is a condition that we see more in the geriatric population of lions versus the younger ones and something that could potentially be something we need to be on the lookout for as our animals get a little bit older," D'Agostino said.

Lions in the wild rarely live to 18, she said.

It could also be a growth in her adrenal gland, ovaries or pituitary gland.

"She could have a small benign tumour somewhere that's actually secreting testosterone," D'Agostino said.

Bridget appears happy and healthy despite her mystery mane. (Gillian Lang/Oklahoma City Zoo)

But whatever caused Bridget's new 'do, D'Agostino said she appears to be perfectly happy and healthy.

"At this point her behaviour is completely normal [and] her health is otherwise normal," she said.

"So I think this is just sort of an incidental finding and something that makes her look a little bit different."