The numbers are staggering: Just 100 years ago, there were 100,000 cheetahs on Earth. Now, 90 percent of these remarkable cats are gone, with human interference hastening their decline.
One woman, Laurie Marker, is at the forefront of the fight to save the world's fastest land animal.
It was 19 years ago that Marker moved from her native California to Namibia, which has the largest cheetah population on Earth. The founder of the Cheetah Conservation Fund, Marker has become perhaps the world's leading expert on -- and fiercest protector of -- these fast and fast-disappearing cats.
Watch "Nightline" at 11:35 p.m. ET TONIGHT for the full story.
"They're so beautiful," she said. "They're the most amazing animal on the face of the Earth."
She introduced "Nightline" to the three 10-month-old cheetahs who live in her backyard: Soraya, Quasar and Phoenix.
These are just three of the 50 cats who live with Marker at her facility in Namibia's Waterberg Plateau. Her foundation now employs 30 people who study and take care of the cheetahs on this sprawling 113,000-acre preserve.
Marker and her team must be sure to provide plenty of exercise for the cheetah cubs -- they are, after all, the fastest land animals on Earth. The cubs chase a rag attached to a pulley, and will eventually graduate to chasing a truck loaded with fresh donkey meat.
Exercise is crucial for the cats, who are designed by nature to chase after prey at speeds up to 80 miles an hour.
The foundation also provides education for students in Namibia and a few of the dwindling number of countries where cheetahs still live in the wild. They learn how to save these animals from their number one predator: humans.
Marker: 'If We Don't Move Rapidly, the Cheetah Is Not Going to Be Around in 20 Years'
"Their extinction is happening now -- and their problems are a man-made and human-caused problem," Marker told a group of students. "If we don't move rapidly, the cheetah is not going to be around in 20 years."
For cheetahs, their greatest asset is also their greatest liability. Their predatory speed has long made them the scourge of farmers, who have retaliated by systematically killing the cheetahs in order to preserve their livestock.
It was a shooting by a farmer that brought Soraya, Quasar and Phoenix into Marker's care.
"They came in when they were 2 days old," Marker said. "A farmer shot the mother, who was term pregnant. And he could see them moving in the stomach. It's kind of a grim story."
She has now come up with a counterintuitive way to stop farmers from shooting cheetahs. She's using dogs to save cats.
One initiative of the Cheetah Conservation Fund is to breed dogs that are then provided to farmers to protect their animals from cheetahs.
In Namibia, the program has been a roaring success. Farmers who have the dogs have almost entirely stopped killing cheetahs, and other countries are following suit.
"They grow up in the flock and then they act as a guardian. So what they do is they bark loudly," Marker said.
She insists that the domesticated dogs can take on the wild cheetahs.
"If they have to ... they will fight to the death," she said.
As it turns out, they usually don't have to: A fascinating cheetah paradox is that while they are ferocious hunters, they are downright timid compared to other big cats.
In fact, for centuries, they've proven easy to domesticate.
"The cheetah has been revered by kings, emperors and princes for thousands of years," Marker said. "Maharajahs had stables of them and would take them hunting."
Their relatively docile personalities, which may endear them to humans, can hinder their survival in the wild.
Some Cheetahs Too Attached to Handlers to Survive in Wild
Cheetahs tend to rely on their extraordinary speed rather than overt aggression. As a result, they often lose their prey to more belligerent predators, like lions and hyenas.
Some of the cheetahs at this reserve -- like Quasar, Phoenix and Soraya -- are too attached to their human handlers to be released back into the wild.
"When you bottle raise them, they become pretty social," Marker said.
Others, however, have been successfully released.
Still, these modest successes may not be enough for this magnificent, but fragile, species. The fate of these beautiful cats is also imperiled by loss of habitat due to human encroachments, and a lack of genetic diversity, which leaves them highly susceptible to disease.
Marker said she is keenly aware of this fact. One of her most beloved cats is Chewbakka, whom Marker adopted 14 years ago. He's been an ambassador for his species and a companion for Marker, but he's reaching the end of the line.
During "Nightline's" visit, she tried to comfort the aging cat.
"Oh, Chewbakka, it's not that easy anymore," she said.
It was a reminder of how much she loves these animals, as well as the difficult road that lies ahead.
"Everything about them is amazing," she said. "They are truly beautiful. They are going away."
For more information on the Cheetah Conservation Fund, CLICK HERE.