It started out as video evidence.
"I was telling people, 'Oh, my rats know how to fetch,' " said Abby Roeser, 16. "But then people would come over and [the rats] would just hide the whole time."
So the Elkins Park teen set up a camera and taped Nami and Pepper doing things adorable (Fetch the ball!), cringe-worthy (Jump onto my leg!), and impressive (Dive underwater!).
Ten months later, Abby's YouTube video "15 Incredible Rat Tricks" has logged 521,693 page views. She's been featured in the New York Post and the Humane Society's national magazine, and was invited to be on America's Got Talent.
She had to turn down the reality TV competition for the same reason she shot the video in the first place - rats are shy.
"They get like this when people are in the room," Abby said in an interview at her home, trying to coax Pepper out of a pouch in her cage. Meanwhile, Blue, another rat, paced the perimeter of the room, occasionally getting close enough to sniff a reporter's boots.
With Abby, the rats are right at home. They cuddle on her while she does her homework, scurry around her room, and peek out from behind her long brown curls in her Facebook profile photo.
Her mother, Mindi, said she has had to gradually desensitize herself to even be in the same room with the rats.
"I think they're very cute," she said. "But it's instinctual, the screams that come out of me."
Abby started out by training her dog, Scruffy, when she was in third or fourth grade. She's had other pets - guinea pigs, hamsters, lizards, etc. - but decided to get rats last August for practical reasons.
"I'm going to college in 2015," she said, and rats only live two to three years. "I didn't want to get something I was going to fall in love with and then have to give away."
She was also attracted to their intelligence and intense focus. Before shooting the video, Abby spent seven months training Pepper and Nami, an hour or two per week.
When she had taught them all the tricks she'd seen on the Internet - spinning and fetching and other feats of agility - Abby came up with some more theatrical ideas.
Like "The Dramatic Teddy Bear Rescue," in which Nami reels in a few feet of string to pull a teddy bear out of the jaws of a hippopotamus and onto the safety of Abby's dresser.
And then there's the video's finale.
"Nami, I need a Band-Aid," Abby says.
The white rat runs over to a first aid box, releases the latch, fetches a bandage, and places it in Abby's hand.
The teen is nonchalant about her training prowess, saying, "When you start training, it just really makes sense. . . . It's all about timing and not expecting too much."
But it's clear she has a knack for it. Training any animal takes a lot of patience and an ability to relate to the animal, "to see it the way that they see it," Abby said.
Her older brother gave up trying to teach Scruffy, a shih tzu, to roll over. "He would just go over to my dog and roll over and expect my dog to understand that and do it, too."
People who watched the video began asking Abby questions about pet rats and animal training. She set up a separate Facebook page to handle the requests, and it's become a forum for more than 1,000 rat-lovers across the country.
"I don't know any of them," Abby said.
She used the forum to raise money this summer when Nami needed to have a tumor removed. And the Facebook friends offered many kind words when Nami didn't make it through the surgery.
Abby has fostered five rats through Philly Rat Rescue, a volunteer group that pledges to find homes for domesticated rats. After Nami's death, she kept one, Blue, as a playmate for Pepper. Abby had bottle-fed the white, red-eyed female from infancy.
This winter, on a four-week break from Germantown Friends School, Abby plans to work as intern at the Philadelphia Zoo.
She said she'll be helping to train some of the rats in KidZooU, and working with miniature horses, pigeons, and parakeets.
Abby said rats can make great pets, but they aren't exactly low-maintenance.
"They're so smart, you can't just put them in a cage and expect them to entertain themselves," she said.
But if you invest the time, they might return the favor by doing some chores. Like trick No. 13 on the video, "Do the Laundry."
That's the one in which Nami takes tiny paper socks and places them in a tiny cardboard washing machine.
5 -- litters in a year for some mating pairs of rats.
15 -- pups in some of the largest litters.
95% -- mortality rate in a rat's first few weeks of life.
5 -- weeks of age when a rat can reproduce.
15 -- weight in pounds of the largest Gambian Pouched Rat.