Asian elephants like Rani are among the largest land mammals in the world. But on Friday, it was a much smaller animal’s appearance that zookeepers believe led to Rani’s demise.

A small stray dog found its way into the zoo on Friday afternoon, eventually winding up near the Elephant Barn, an area off-limits to the public, the Saint Louis Zoo said in a statement. The dog’s presence — and the subsequent commotion to capture it — “agitated” an elephant outside the barn.

While the chaos to collect the lost dog unfolded outside, Rani was in her bedroom having dinner. But the vocalizations of the other distressed elephants seemed to reach her ears, and the zoo’s Elephant Care team saw her grow agitated in response. The team watched Rani as she briefly circled and vocalized. Then, the 27-year-old elephant collapsed.

The care team jumped to action to provide emergency care, the zoo said.

“Our team of professional animal care experts did everything possible, but we couldn’t save Rani,” Saint Louis Zoo Director Michael Macek said in a statement, describing the staff as “absolutely devastated.”

Rani’s human care team and elephant family spent the rest of the evening saying their goodbyes.

“Rani was a special member of this elephant family group,” Katie Pilgram-Kloppe, zoological manager of the River’s Edge, said in a statement. “She loved playing with her sisters Maliha and Priya. While growing up here in St. Louis, she got to learn from her own mom, Ellie, on how to be an amazing mother herself. She had a great relationship with her animal-care team and all of the other elephants. When socializing with her family she made a unique squeaking noise that her daughter Jade also mimics.”

The initial results from Rani’s necropsy reveled “some preexisting changes in her heart,” the zoo’s pathologist said, but further testing is planned to determine if they played a role in her death.

Rani’s death leaves the River’s Edge elephant family with eight survivors, including her mother and daughter, as well as her father, Raja.

Asian elephants such as Rani are increasingly rare, with their numbers dwindling because of poaching and habitat loss, according to the World Wildlife Fund, which estimates there are 40,000 to 50,000 Asian elephants left in the wild.

The zoo said, following Rani’s death, that the rest of the herd calmed down and is doing well. The stray dog was caught and taken to a local shelter. It’s still unclear how it entered the zoo.