There Are 4 Of These Rhinos Left In The World, And One Of Them Is Sick

She's one of four northern white rhinos left in the world, and something is wrong with her.

Nola, who is 41 years old and lives at San Diego's Zoo Safari Park, is suffering from an abscess on her hip that won't go away. Veterinarians are trying to get to the source of what's making her sick.

"To get to the source of her infection, Nola underwent a medical procedure in the field today," the zoo wrote on Facebook. "We don't have a definitive answer at the moment, but we're keeping a close eye on our girl and making sure she is comfortable."

Because the subspecies is almost extinct, each northern white is especially precious. Conservationists are racing against time to try to develop groundbreaking technology to breed the few aging northern whites left .

As Nola is undergoing treatment and tests, her southern white rhino friend, Chuck, is being kept apart from her.

Here's hoping Nola recovers completely soon. Watch footage of Nola, one of the rarest animals left on earth, below.