"I like watching him have fun," Lozach said.
Although the dogs have hunting instincts, it takes training to capitalize on them. Just because your pet runs after backyard squirrels doesn't mean it could ever catch one.
When at its best, the alley pack works together. One dog will sniff out a rat and signal its whereabouts, often by barking. Another leaps at the hideaway to rout the quarry, and then a third lurches to catch it as it flees. A rat that scuttles into the open might get caught in a rundown, or even a tug of war, between dogs that circle and flank it.
After making a kill with a bite or a shake, the hunters trot back, rat in mouth, and allow their owners to take it from their jaws. The night's kill ends up in a trash bin.
There's no official estimate of how many rats rove the city's streets, basements, parks, and subways. But there are plenty.
Officials have tried a number of innovative tactics to rout them, including a 2007 city Health Department initiative that sent inspectors with hand-held computers to map infestations in a Bronx neighborhood and then followed up with owners to address the problems.
But the terrier forays are an unofficial undertaking, and participants say they're less about killing rats than giving dogs the experience of chasing them. The Health Department declined to comment on the hunts.