An initial exam indicated Rose had not eaten in weeks, Dr. Alex Herman, the zoo's vice president of Veterinary Services, said in a statement Tuesday. The cub, estimated to be about five months old, weighs just 8.8 pounds. The average female cub her age should weigh about 30 pounds.
"She is excruciatingly thin. To survive, her body resorted to consuming its own muscle mass," Herman said. The cub is also suffering from extreme dehydration, "and her temperature was so low it couldn't even be read."
VIDEO: Mountain lion cubs adopted by Ohio zoo after being orphaned by Redding wildfire
Hikers first spotted Rose at the Thornewood Open Space Preserve in San Mateo County and reported the sighting to authorities, who sent a team of biologists and wildlife officials to find the cub.
The search took five days.
After a day of treatment, veterinarians are guardedly optimistic about Rose's recovery. She is receiving fluids and hydration intravenously and being bottle-fed small amounts of formula several times a day.
"We can already tell she has a feisty spirit and an obvious will to live, and we're thankful for that," Herman said.
VIDEO: Rescued mountain lion cub 'Captain Cal' gets bandages removed from paws at Oakland Zoo
Rose is the 18th orphaned mountain lion cub Oakland Zoo has received and rehabilitated from the state since 2017, zoo officials said.
Three of the 18, Coloma, Toro, and Silverado, still reside at the Oakland Zoo.
Check out more videos of mountain lions here.