Some of the guys who show up for happy hour at the Bark Bar don't bother with formalities when they spot a female.

They get directly to enthusiastic sniffing.

Denver Dog Bars
"Mozie" stands on a picnic table while at the Bark Bar at 4132 W. 38th Ave. with her owner Tauni Clark. The fenced area at the bar was filled with pooches and their owners on Friday, February 28, 2014 for the happy hour, which drew the giant breeds for Big Dogs Big Paws. (Cyrus McCrimmon, The Denver Post)

Of course, dogs can get away with the sort of behavior that would not end well if the mammal at the other end of the leash tried it. The humans do their share of scouting the opposite sex, but they trade puppy tales instead of sniffing each other.

In an age of craft beer and effete cocktails, some pubs literally are deciding to go to the dogs. From Oregon to Florida, bar owners are finding that mixing drinking and dogs is good for business, especially in Denver, which surveys rank among the country's top dog-friendliest cities. And not just those little dogs that fit in purses, either.

Denver Dog Bars
MK Wohlenhaus hugs her dog "Epoch" while at The Bark Bar. (Cyrus McCrimmon, The Denver Post)

Service dogs have always been allowed in these establishments. But dog bars also welcome Great Pyrenees, Bernese Mountain Dogs, mutts, Tibetan Terriers and just about any other relatively obedient canine with a cold, inquisitive nose.

Denver dogs and their owners can visit at least three local bars that offer a canine play area — the Bark Bar, the Watering Bowl, and the Ugly Dog Sports Bar. Local 46 currently allows dogs on-leash in its backyard beer garden, and the Tavern Uptown plans a remodel that will include a dog patio with a self-service bar.

The Bark Bar and the Watering Bowl both offer fenced outdoor spaces that are the equivalent of small dog parks, with outdoor seating and tactfully-placed plastic bags and scoops.

"A dog park is what inspired us — my husband and I at the Berkeley dog park with our two dogs, and he wanted a coffee, and I wanted a craft beer," said owner Catherine Peters.

"I said, 'Wouldn't it be great if there was a dog park bar?' and he said, 'Sweetie, you should do that.' And we opened on Christmas Day last year. Best Christmas present ever!"

It's a concept whose time has come, says University of Denver adjunct professor Shadi Farhangrazi.

"Look at the demographic: In Colorado, we love our dogs, we love being outside, and we love fun, so this idea really is quite innovative. I'd compare it to other innovative trends, like having a Starbucks inside a Barnes & Noble so people buy coffee but maybe a book or magazine also, and having a cafe inside a supermarket like Whole Foods."

Like all restaurants and bars in Denver, dog bars are governed by city health code and animal regulations that require public access to the patio or open area, to prevent dogs from going inside the business. Patrons must fetch their own drinks. Having a private off-leash dog park means jumping another hurdle — getting approval from the board of environmental health.

Each dog bar also imposes its own rules on patrons. The Bark Bar rules allow dogs off-leash but under voice control, but doesn't allow children in the puppy yard. Most dogs romp freely and cheerily. Peters intervenes if unfriendly teeth are bared.

Otherwise, it's Yappy Hour all the time. Happy Hour, however, is only from 4 to 7 p.m., with $1 off wine, draft and well drinks. Happy Hour pricing doesn't apply to specialty drinks, like the Hot Buttered Rump ( Kraken spiced rum, brown sugar, cloves) or the Bowser Beer (chicken broth, glucosamine, malt barley). The former targets humans; the latter is for the puppies.

Megan and Kevin Boniface settled for beers recently. Their Greater Swiss Mountain Dog, Senna, rambled around the Bark Bar's pocket dog park, greeting other dogs according to the nose-to-tail custom.

"How can you beat this?" Kevin Boniface asked, lifting his plastic cup.

"We get to drink beer, and our boy gets to socialize!"

Jason Harlacher , who was there with a beer and Wrigley, his English cream golden retriever, agreed. On Tuesdays, he brings Wrigley for a romp at the Bark Bar yard before taking him home and heading off to Trivia Night at another pub.

"We come here three or four days a week, and a lot on weekends," Harlacher said.

"He knows when we're coming here, and he's very happy. He's a very social dog."

Devany McNeill, executive director of the local independent restaurant association Eat Denver and owner of a West Highland terrier, said she loved "the idea of being able to bring your dog along when the weather is beautiful.

"Although," she added, "I remember being in France 15 years ago, and seeing dogs at tables in nice restaurants, which was sort of gross. But outdoors? I love that we can do that in Denver."

Claire Martin: 303-954-1477, cmartin@denverpost.com or twitter.com/byclairemartin