Sarah the cheetah, who shattered the world record for the standing 100-meter dash in a feat photographed by National Geographic magazine, was euthanized this week at the Cincinnati Zoo.

At 15, Sarah's quality of life was diminishing—a cheetah's average life span is eight to twelve years.

“She lived a full life and was a phenomenal ambassador for her species,” said Linda Castaneda, lead trainer for the Cincinnati Zoo’s Cat Ambassador Program.

“She was a dynamic individual and we were privileged to know her and learn from her. We will all miss the princess cat.”

World's Fastest Runner A high-speed camera captures the cheetah's two-second sprint in slow motion, revealing every stride.

During a photo shoot in 2012, the then-11-year-old cheetah was radar-timed at up to 61 miles (98 kilometers) an hour. In a 100-meter trial, Sarah clocked a time of 5.95 seconds—making Olympian Usain Bolt's world record of 9.58 seconds look positively stodgy by comparison. (Also see "Filming the World's Fastest Runner.")

The record-breaking sprint, which occurred on a USA Track & Field-certified course established by the zoo, is the fastest timed 100 meters ever run by anything on the planet. (See "Super Animals: Fast Fliers, Heavy Lifters, and High Jumpers.")

"She looked like a polka-dotted missile," National Geographic photo editor Kim Hubbard said at the time. "I've never seen anything alive run that fast."

With a flexible spine that enables a 22-foot stride, cheetahs have a perfect body for speed. Their hard, cleat-like claws also give them traction while running.

Cheetahs 101 You may already know that cheetahs are the world's fastest land animal. But did you know their tails play a crucial role in hunting? Check out this and other fun facts about cheetahs.

As astonishingly swift as Sarah's world record time of 5.95 seconds might seem in a human context, it's almost certain that cheetahs in the wild—lean, hungry, chasing down antelopes for their own survival or that of their cubs—have run considerably faster.

However, their speed hasn't helped them tackle threats to their survival in the wild. The big cats, which live in Africa and Iran, have dwindled from about 100,000 in 1900 to an estimated 9,000 to 12,000 individuals today, particularly due to widespread loss of prey and habitat. (See National Geographic photos of cheetahs on the edge.)

The International Union for Conservation of Nature lists the species as a whole as vulnerable to extinction, with smaller populations in Iran and northwestern Africa categorized as critically endangered.