SAN DIEGO - When she arrived from Los Angeles, she was comatose, dehydrated, malnourished and severely undersized.
Only round-the-clock emergency care in an aquatic intensive-care unit at the Sea World theme park kept the week-old calf from dying.
Now, 14 months later, J.J., the orphaned California gray whale, is healthy, robust and about to return to her natural environment.
At 30 feet long and 18,000 pounds, she is considered the largest mammal ever kept in captivity.
If a joint operation by Sea World, the Navy and the Coast Guard is successful, she will be lowered back into the Pacific on Thursday.
There she'll join others of her species on their annual 5,600-mile migration from Baja California to the coast of Alaska.
Other sea mammals - principally sea lions - have been nursed back to health at marine facilities and released.
But none was as large as J.J., none had been as near death, none was studied by scientists as closely, and certainly none had captured the public's imagination as strongly.
Beyond being a veterinary medical marvel for her recovery, J.J. has also proved a boon to scientists trying to unlock the secrets of her mysterious species.
From J.J.'s blood, they have developed an antibody serum to aid other whales that are found in distress along beaches and coastal shallows.
But make no mistake: Her return to the ocean is highly problematic.
Will she know how to feed herself, or has she become dependent on handouts?
Will she know instinctively to avoid pods of potentially murderous killer whales?
Will she head north to Alaska or get lost and swim aimlessly in the ocean?
"We understand there are unknowns out there," said Jim Antrim, Sea World's general curator of mammals.
"Nobody has ever done this before."
John Heyning, curator of mammals at the Los Angeles County Museum of Natural History, who helped rescue J.J. and has monitored her recovery, gives her "much better than a 50-50 chance of survival."
He added: "You have to remember that when we first spotted her Jan. 10 (1997), she had zero chance. She's as ready to go as she can be."
A 13-foot-long newborn
When Heyning and an ad hoc squad of Los Angeles police officers, lifeguards, whale experts and gung-ho bystanders intervened, the disoriented whale calf had become separated from her mother, was floundering and still had her umbilicus attached.
At 13 feet, 8 inches, and 1,670 pounds, the week-old whale was so stunted that her ribs and skull were visible beneath her skin.
With a police escort, she was rushed by truck to Sea World.
At Sea World, she has been slowly nursed back to health and given a name (after the late Judi Junes, director of operations for the Friends of Sea Lions Marine Mammal Center in Laguna Beach).
She cannot be kept
Adult female gray whales average 46 feet and 70,000 pounds at maturity, and thus keeping J.J. in captivity forever was never an option.
At 8 months, she was weaned off a gooey white formula of vitamins and pureed fish.
These days she averages 475 pounds of fish a day: white bait, capelin, herring, squid, krill, sardines and small shrimp. Keepers maintain their distance.
"We've wanted to keep her as wild as possible," said senior animal-care specialist Kevin Robinson. "We don't want her to be looking around for humans to feed her or pet her."
One promising sign has been J.J.'s temperament: standoffish.
Her keepers interpret this as self-assurance that will serve her well.
She seemed neither interested nor spooked by a dolphin and two sea lions that were introduced into her solitary pool briefly.
One of the unknowns about J.J.'s return to the ocean is how she will react to killer whales. There have been several instances of killer whales attacking gray whales off the California coast.
This much is known: When the gate between J.J.'s tank and that of Sea World's killer whales was opened, J.J. became agitated as if she sensed danger. Caretakers took that as a good sign.
How J.J. will be set free
Weather and sea conditions willing, J.J. will be lifted from her pool on Thursday morning in a specially fitted 32-foot stretcher hoisted by a 20-ton cargo boom.
She will be eased into a container padded with foam to make a comfy, snug nest.
The container, set on a flatbed truck, will be open to the sky to provide oxygen. J.J. will be kept wet by hoses and misters on the trip to a naval station.
Once on the base, a crane used to put heavy equipment and armaments aboard warships will be used to lift J.J. from the container and onto the deck of the 180-foot Coast Guard buoy tender Conifer.
A Coast Guard helicopter and a Sea World single-engine plane will have scouted the waters off San Diego's Point Loma for any whale pods traveling nearby.
The goal is to release J.J. near a pod in hopes that she joins the group.
To allow her movements to be tracked, researchers will equip J.J.'s back with four transmitters.
The transmitters will collect information on her location as well as her dive depth and duration.
The transmitters will be uplinked to a satellite whenever J.J. surfaces. Ideally, they should last 18 months.
At Sea World, where J.J. has been nursed, fed and cared for, her departure is tinged with sadness.
"Some people have suggested it'll be like watching your child go off to school for the first time," said veterinarian Thomas Reidarson. "It's not. Your children come home again."