The Smithsonian’s National Zoo and Conservation Biology Institute is mourning the loss of a charismatic and pioneering member of its herd. Shanthi, a female Asian elephant who had been under the Zoo’s care for nearly 44 years, was euthanized yesterday to alleviate suffering from advanced osteoarthritis. She was 45.

“Generations of staff and visitors have come to know and love Shanthi and, by extension, Asian elephants,” said the Zoo’s director Steven Monfort said in a statement . “Her contributions to research and medicine have made an indelible mark on our efforts to save her wild counterparts from extinction, as well as improve the lives of her fellow animal ambassadors. Over the past few years in particular, our elephant and veterinary teams have gone the extra mile to ensure Shanthi’s physical, social and mental well-being. They have her best interest at heart, and I am grateful for their professionalism in providing her with extraordinary care and compassion.”

Osteoarthritis is an especially debilitating disease in larger animals, and animal care staff monitoring Shanthi’s condition recognized that her quality of life had significantly diminished recently after several years of successful management.

Researchers know more about the life histories of African elephants in the wild than they do about Asian elephants, but it is known that the median lifespan for female Asian elephants under human care is typically around 46 years.

Although elephants can’t directly tell people when they are experiencing discomfort, changes in behavior, appetite, locomotion and sociability can indicate pain. These changes would be easily recognized by an elephant manager like one of Shanthi’s who had worked with her for 32 years. By using medical testing to monitor stress hormone levels and inflammatory markers, keepers can also gauge the severity of a condition.

The Zoo reported in a press release that keepers and care staff had used several innovative treatments over the years to help mitigate the impacts of Shanthi’s degenerative condition. She was the first of her kind to receive therapies including injections of a protein serum to slow disease progression.

“We were able to do some things to help that wouldn’t be available to an elephant that was in the wild,” says the Zoo’s senior curator Bryan Amaral. “Shanthi is one of the most studied elephants in existence probably, and she helped us with several research projects, [including] some of the early work with artificial insemination and endocrine hormone monitoring, and elements for both the estrus cycle and pregnancy as well.”

Notably, in 1996, Shanthi was the first elephant to be artificially inseminated, using a novel technique with daily hormone monitoring. This process is now used around the world to aid in conservation management efforts. Shanthi’s son Kandula, born via this method in 2001, lives at the Oklahoma City Zoo.

Shanthi came at the National Zoo in 1976, after living roughly the first year of her life at the Pinnawela Elephant Orphanage in Sri Lanka. She arrived as a gift to the United States from the children of Sri Lanka.

Elephants are known for their highly social, intelligent nature. Observational behavioral studies suggest they also engage in a form of grief and mourning, comparable in some ways, to humans. Among Shanthi’s herd mates who were given an opportunity to access her after her passing were Bozie and Swarna, two elephants who were also part of the same group of Sri Lankan orphans to come to America and who were reunited many years later at the National Zoo.

“Bozie and Shanthi were really close. I don't know if that was any sort of residual relationship that they had. If they recognized each other, or they just hit it off better when they reunited, it’s hard to say,” says Amaral.

“We give them access to let them know what it’s all about and to help them move forward, and generally speaking they do that relatively quickly.” Amaral noted that Bozie and Swarna’s behavior toward the deceased Shanthi included normal touching and smelling, which was expected based on their relationships and their previous experiences with death.

The Zoo recently lost another beloved Asian elephant in March when the 72-year old Ambika was euthanized following irreversible health decline. Ambika was the third oldest Asian elephant in the North American population.

Asian elephants are considered endangered; conservation scientists estimate the total world population to be around 30,000 to 50,000 individuals. Shanthi, who readily participated in hundreds of behavioral and biological research studies, will be remembered for her unrivaled contribution to conservation efforts.