A man's best friend, it turns out, can also be best buddies with the world's fastest mammal.
Cheetahs – endangered animals that are skittish and often fail to breed in captivity – are being paired with "companion dogs" who serve as playmates and sometime-guides for the big cats.
"It is all about comforting and reassuring the cheetah," said Janet Rose-Hinostroza, animal training supervisor at the San Diego Zoo Safari Park.
The San Diego zoo is the top U.S. breeder of cheetahs in captivity. In the past 40 years, 135 cheetahs have been born at the park's breeding facility. Of the 19 cheetahs at Safari Park, four have dogs.
The zoo has been pairing dogs with cheetahs for more than 30 years, a practice that has spread to other facilities as well.
The cheetahs most often found at zoos and wildlife parks are not considered good breeding candidates, Rose-Hinostroza said. They don't relate well to other cheetahs, or they are abandoned by their mothers -- but they seem to take easily to companion dogs and look to the dogs for play and example.
The dogs, usually from animal shelters, and cheetah pups generally are introduced when they are about 3 months old. That's the case for Hopper, a 40-pound mutt who hangs out with Amara, the toughest female cheetah on the team, Rose-Hinostroza said.
"His most important role, honestly, is living with Amara -- being comfortable with the cheetah, being her best friend," said one of the zoo's cheetah trainers in a 2011 interview with NBC San Diego.
Hooper and Amara often walk side by side, but when they're traveling in unfamiliar territory, the dog will often go first. If he seems comfortable, Amara will understand "she has nothing to worry about," the trainer said.
One of Safari Park's dogs -- the only non-shelter dog -- is Yeti, an Anatolian shepherd. She works with two cheetahs: Johari and her brother Shiley.
No one is sure when the idea of cheetah dogs started, but Anatolian shepherds helped advance it. The San Diego Zoo was given a pair of cheetahs in 1981 on the condition they be given dogs because they were used to them.
Dogs are the dominant members of their relationships with cheetahs, Rose-Hinostroza said.
"The dog always has the cat's back, but it's never the other way around. Dogs worry about their cats. They protect their cats," she said.
A blog post on the zoo's website recounts the introduction of a 2-year-old domestic female dog and 1-year-old male cheetah. After they got used to each other, the dog began taking the cheetah's leash in her mouth and leading the big cat around.
Although the dogs and cats live together, they are not always with one another. Dogs have play dates with other dogs and humans. Mealtimes always are spent apart. The dogs eat kibble, and the cheetahs eat steak.
"If they ate together," Rose-Hinostroza said, "there would be one really fat dog and a really skinny cheetah."
Below, a 13-week-old Laborador puppy named Max plays with Savanna, a cheetah cub, at the Cincinnati Zoo in September 2012.