To most people, the phrase “rat race” denotes a grim struggle to get ahead in life. But to those attending the annual show of the American Fancy Rat and Mouse Association (AFRMA), in Riverside, Calif., the term has a more literal meaning. The racecourse is a three-by-four-foot wooden box divided into narrow lanes, with four rats waiting behind the starting gates. A judge lifts the gate and they’re off!

Or not. One animal plops down to groom herself. Another stops to sniff at something. Though their owners urge them forward (“Come on, Ruby! Come on, Castiel!”), the contestants remain unhurried, oblivious. By the end, only a small brown female named Dusty has crossed the finish line. But in the affirmative spirit of AFRMA, even the laggards get ribbons.

I’m here because, like a growing number of American families, mine has fallen in love with this less-than-conventional pet. I used to associate rats mainly with the Black Death. Last summer, however, my 9-year-old daughter, Samantha, who’s allergic to dogs and cats and unexcited by fish, lizards, or turtles, was begging for a pet, and the rats at the local Petco aroused her snuggling instincts.

Swallowing our misgivings, my wife and I bought a pair of females from a reputable breeder, and they promptly won our hearts. Ounce for ounce, Cookie and Blueberry have more personality than many conventional domestic animals. They run excitedly to their cage door when we enter the room. They enjoy being tickled (scientists recently found that rats can laugh, at a frequency inaudible to humans) and playing peekaboo behind the sofa cushions. Do they occasionally gnaw the furniture? Maybe. But at least we don’t have to take them for walks—a big plus for an overscheduled modern family.

About half a million families own a rat or mouse, based on statistics from the American Pet Products Association—nearly double the number from 2006. That upswing may reflect the low cost of caring for “pocket pets” at a time of tight household finances. But as small critters go, there’s something about rats that generates particular ardor among their owners. “Mice are great, but rats are smarter,” says AFRMA founder and president Karen Robbins. “They know you, and they want to be out with you.”

Fancy rats come in a dizzying array of configurations. Their officially recognized colors include Blue, Champagne, Lilac, Mink, Siamese, and Lynx. There are straight-haired Standards, curly Rexes, and shiny Satins, with markings classified as Hooded, Masked, Variegated, Berkshire, and Dalmatian. There are hairless rats, tailless rats, and big-eared rats called Dumbos.

Many of these varieties (and a few of their mouse cousins) are on display at the AFRMA show in Riverside. In the “curious rat” competition, which challenges the contestant to investigate 10 items in one minute (house keys, hairbrush, toilet-paper tube, and so on), the black-masked Ruby bustles from one to the other like a shopper at an after-Christmas 50-percent-off sale.

Ruby’s owners, Kat and Derek MacElwain, beam as she racks up an impressive score of 80 percent. “Most people think of rats as cockroaches with fur,” says Derek, 43, a manager of a construction-supply company. “But they’re some of the sweetest creatures around.”

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