SAN FRANCISCO (CBS SF) — The San Francisco Zoo on Tuesday announced the recent passing of one of its most senior residents last week: an Eastern black rhino named “Elly.”

Elly died on Wednesday, May 3, due to age-related conditions. At 46 years old, Elly was the oldest Eastern black rhino in the country by about five years. In a press release, the San Francisco Zoo said, “Her long life speaks to the incredible care she received from animal staff, veterinarians and wellness experts at the Zoo.”

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Elly first came to the zoo more than 43 years ago in the spring of 1974. Over the years, she gave gave birth to 14 calves and additionally had 15 grand calves, 6 great-grand calves and even a great-great-grand calf.

The SF Zoo’s black rhino “Boone” is her grand calf. Elly has helped in the growth and diversity of the captive black rhino population. It is estimated only between 5,042 and 5,455 of the critically endangered black rhinos are left in the wild.

“As one of our longest-standing residents, Elly was an outstanding animal ambassador for the endangered black rhino species, which faces continued risk from poaching, mainly for its horn,” said San Francisco Zoo President Tanya M. Peterson. “We are grateful to have celebrated many wonderful years with Elly, and she will be dearly missed by the Zoo team as well as millions of guests who connected with and cared for her.”

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Her team of caretakers frequently spoil the roughly 1,800-pound rhino, presenting her with a “cake” made of tree browse in the shape of the number 46 on her 46th birthday. Elly’s presence at the zoo helped educate the community about the importance of rhino conservation and how individuals can make a difference.

She played a key part especially during the San Francisco Zoo’s annual observance of World Rhino Day celebrations, held every year on September 22.

As she got older, the Zoo’s veterinary and animal care staff closely monitored her health and quality of life. On Wednesday, May 3, underwent exploratory surgery to examine one of her legs, which appeared to be bothering her. The veterinarian team of experts concluded her condition had deteriorated and could no longer be treated while still maintaining a positive quality of life. They made the difficult but humane decision was made not to wake Elly from her surgery.

The San Francisco Zoo encouraged fans of Elly to visit the International Rhino Foundation website to learn more about conservation efforts as a way to honor her memory.

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