NEW YORK -- Until he was 10 years old, Petro lived the life of an ordinary house cat.
He was a slim black tom with a white throat who belonged to a family on a street called First Place in Carroll Gardens, Brooklyn. Petro ate and stretched, played with stuffed animals, dozed in a beanbag chair.
When the couple had a second child, something changed.
"He was the baby," said Petro's owner Jennifer Chi. "He wasn't getting enough attention anymore, and he was jealous."
Petro began to seek attention elsewhere.
Everywhere else, in fact.
Upstairs to scratch on neighbors' doors until they let him in, out the front window of his first-floor apartment and onto the sidewalk to demand pats and head-scratches from passers-by.
Now at age 13 he is a local celebrity: Petro, the Cat-Mayor of First Place.
On nice days, Petro, his coat flecked with silver, patrols the block, from the corner of Clinton Street almost to the far end at Court Street. He delights children, greets strangers and friends, poses for photos, terrifies dogs (or imagines he does).
"He'll sit in the middle of the sidewalk," said Richard Fluker, who delivers parcels for the Postal Service. "You have no choice — you have to go around him. He's not afraid of anyone."
From Petro's collar hangs an ID tag shaped like a fish. "We used to get four or five calls a week from people who 'found' him," said Chi's husband, Jason Glenn. "People wake you up at 1 in the morning holding your cat in the doorway. We felt like taping to the tag, 'It's all right for him to be outside.'"
Some experts urge urban cat owners not to let their pets out, to avoid disease or violence. But the outdoors have been pretty good to Petro. He turns out to be allergic to ragweed, but he gets shots. He had a feline rival for a while, but he seems to have vanquished him.
In any case, Petro has constituents to attend to.
"Most cats are kind of like 'I really don't care,'" said Emma Butler, 12, who goes to school nearby. "But a few weeks ago, I saw this little girl, she fell off her scooter. She was crying and bleeding — she was 5 or something. The cat went right up to her, meowed in her face, and she started laughing and hugging him."
When the weather is less agreeable, Petro makes house calls in his five-story brownstone.
"One time he somehow got into my apartment," said Tommy Mulvoy, a teacher who lives on the top floor. "I turn around and this freaking cat is on the back of my couch. How my cat didn't see him, I don't know. He's a sneaky dude."
John Bradshaw, a British anthrozoologist (or student of the human-animal bond) and the author of "Cat Sense," said that while most cats quickly resume their old lives after the disruption of a new baby, a few change permanently.
"It's a common trait among cats that they're constantly kind of reviewing their options and looking for somewhere else to live as a fallback," he said. "My guess is that Petro is an extreme case of that."
This is how Petro spent Feb. 22, a mild, brilliant Monday:
At 11:06 a.m., he squeezed out the window, groomed on the stoop, descended the stairs, stuck his head through the wrought-iron gate and blinked sleepily at the sidewalk.
It was the still of the day. Petro wandered through yards, scratched at the base of a broad tree, returned to the sidewalk. A girl about 4, walking with her grandparents, stopped to pet his head. They pulled her along. She glanced back longingly.
At 12:20 p.m., Petro was sprawled in a sun patch on the sidewalk when he sensed a dog. He jumped up, leaf litter stuck to his flank, and took a strategic position behind the fence.
"Molly, be good," said the man walking the dog.
As the black-and-gray mutt passed by, Petro sprang up, charged — then stopped inside the fence just out of reach, back arched, fur standing.
Molly turned toward him but was yanked away. Mission accomplished.
At 12:25, Petro bounded up the steps of another brownstone three houses from his to greet Erna Blumhardt. She set down her groceries to scratch his head but would not let him in.
"Not today," she said.
Then her downstairs neighbor David Sandholm came home. Petro slalomed between his legs and followed him inside.
"He's the perfect pet for us," said Sandholm's wife, Carolyn. "We don't have to clean out a litter box."
The Sandholms have never met Petro's owners.
David Sandholm gave Petro some treats and sat on the couch with a sandwich. Petro got up on the coffee table to sniff it. After lunch, he took a nap on David Sandholm's computer keyboard.
Around 3 p.m., a young man and woman in Verizon jackets came up the steps of Petro's building. Petro approached questioningly. The man extended a hand for him to sniff.
Petro followed the Verizon reps as they went door-to-door selling high-speed service. When they entered the house on the corner on Clinton, Petro waited for them on the stoop.
But the afternoon deepened and shadows swallowed up the sunny side of First Place.
Petro strolled back to his building and climbed in the window.
It has been a good run, but Petro's tenure on First Place is nearing an end. His family is moving soon to Woodhull Street, a few blocks away.
Petro should find the new surroundings — another brownstone on the sunny side of a street — reasonably homey. The neighbors four houses down have a hummingbird feeder.