One day before its baby elephant was going to turn 3 months old, Pittsburgh is instead mourning the calf's death.

"All of us tried really, really hard and did our best for her," Pittsburgh Zoo and PPG Aquarium President and CEO Dr. Barbara Baker said through tears just one hour after the calf was euthanized. "I believe we're very blessed to have a chance to know her. She's a wonderful spirit."

"This little girl really captured a lot of hearts," she added.

The baby elephant, who Baker referred to as "Little Bit," had a difficult and short life. She was born 30 days premature at the International Conservation Center in Somerset County and transported to the zoo because her mother was not producing milk and showed little interest in caring for her offspring. Officials hoped to eventually introduce her to the zoo's herd, allowing her monitored interactions with the matriarch in the interim.

The calf's painful teething process posed a critical problem. All four molars erupted at once instead of one tooth at a time, and she stopped eating as a result of the pain. Last week, veterinarians surgically inserted an esophageal feeding tube to give the calf nutrients while bypassing the pain in her mouth.

She had maintained weight for brief periods but had never gained any, even after the feeding tube was inserted. The calf weighed 184 pounds at birth--54 pounds less than an average African elephant at birth--but was down to 169 pounds by the time officials opted to intervene with a feeding tube. She was down to 166 pounds at her last weigh-in. A healthy elephant calf is expected to gain about 1 pound every two days.

Elephant manager Willie Thieson, Baker and the zoo's veterinarian team decided last night to euthanize the calf. She died at 10 a.m. today surrounded by her caretakers.

"We really want to thank everybody," Baker said. "We've got a tremendous amount of support, prayers, offers of help from all across the country--really, all across the world. And we really, really appreciate that. They're very helpful, and we really hoped that we would be able to help her gain weight and pull her out."

Caretakers were feeding the calf a diet of half formula and half milk from one of the zoo's adult elephants. They had the mixture analyzed by the Smithsonian Institution to ensure it contained adequate nutrients and fats to help the baby gain weight and grow.

"We suspect because she had not been able to gain weight--" Baker said, pausing to collect herself. "You know, she was a feisty calf, and she had a lot of fight. So we searched high and low to try to figure out why she's not gaining weight. She should be gaining weight, you know? At this point she should be a healthy 200-plus pounds, and at last weight she was 166."

Veterinarians are performing a necropsy to determine why the calf was not able to gain weight even though she met or exceeded all other milestones. They will take a variety of samples from the elephant's body to find any underlying health issues. It will take about 8-12 weeks for those results to come back.

"We've always suspected, particularly over the last month, that we were dealing with some type of birth defect where she could not absorb nutrients and was not able to gain weight normally," Baker said.

After the necropsy, they plan to bury her at the International Conservation Center.

The zoo will also use this experience to aid African elephant care in Pennsylvania and worldwide. Throughout caring for the young elephant, the Pittsburgh Zoo consulted with organizations across the globe, hoping to glean insight that might save the calf. They hope the caretakers' ample notes and necropsy results will help other zoos and elephant organizations in the future.

But animal rights organization PETA is calling for the zoo to end its elephant program altogether.

"This elephant's short life ended without the comfort of her mother or other elephants," PETA said in a statement. "The Pittsburgh Zoo has publicly glossed over the apparent true extent of the health crisis that this unnamed baby must have suffered--and from taking her away from her mother to dropping its accreditation so that it can keep using weapons on elephants, its elephant program is a throwback to a crueler age."

Baker said elephants are a common topic for some animal rights groups and anticipated criticism. She added that their African elephant program involves an intensive process to establish relationships and trust with the animals. They plan to continue the breeding program.

She said the zoo's caretakers are the experts, not animal rights groups.

"I have absolutely no discomfort and no doubt that our team and our staff did everything possible that they could to care for this calf," she said.