Dogs from petite papillons to muscular Rottweilers showed off their four-footed agility on Saturday at the Westminster Kennel Club dog show, tackling obstacles from hurdles to tunnels. And next door, so did some decidedly rare breeds for the Westminster world: cats.

For the first time, felines sidled up to the nation's premier dog show, as part of an informational companion event showcasing various breeds of both species.

It included a cat agility demonstration contest, while more than 300 of the nation's top agility dogs vied in a more formal competition.

It didn't exactly mean there were cats in the 140-year-old dog show, but it came close enough to prompt some "what?!" and waggish alarm about a breakdown in the animal social order. Some Twitter users have portrayed the development as a sign of impending cat-astrophe.

A satirical Chicago Tribune column declared that "we can't just let cats start racing across the borders of traditional dog events."

Even some Westminster competitors found the juxtaposition jarring - or "so weird," in the words of Hannah Naiburg of Milford, Connecticut, who guided her terrier mix, Molly, in Westminster's agility contest.

But others tipped their hats to the cats that were padding and prowling around their own course, most of them trying the sport for the first time.

"Good for them," said Tina Ackerman of Goffstown, New Hampshire, who handled her bichon frise, Bubba Watson. "There's no way we could ever have trained any of our cats to do agility."

Bemisu, a 1-year-old sphinx cat nicknamed Misha, had never tried the sport before Saturday. But within a half-hour, she was following owner Blake Gipson's toy-dangling signals to hop through hoops and run through a mesh tunnel - so well that she bested about 30 other cats to win.

If Saturday's "Meet the Breeds" event - sponsored by Westminster, the American Kennel Club and The International Cat Association - gave felines their first chance to share Westminster's spotlight, it also illustrated that there's plenty of everyday crossover between the dog and cat camps.