In one of three "Liberty" sequences, Frédéric Pignon, equestrian co-director, puts Spanish-Friesian stallion Aetes through his paces. The equestrian extravaganza "Cavalia" combines Cirque-style aerial and acrobatic acts with performances by horses and riders.

For centuries, the canine has reigned as humanity's official "best friend."

But the creators and stars of "Cavalia" -- including its 54 equine performers -- make a case for the horse. Of course.

After all, horses and humans lived side by side for thousands of years, notes "Cavalia's" artistic director, Normand Latourelle, a Cirque du Soleil founder who was with the troupe from 1985 to 1990.

"After 5,000 years, we've replaced horses with horsepower," Latourelle says. But "it's the most fabulous creature in the world," he adds. "It's our best friend."

The equestrian extravaganza -- which adds an equine element to Cirque-style acrobatics, music and dance -- continues through Dec. 9 at the Rio, beneath a custom big top that, at 110-feet high, is the largest touring tent in North America. (The Rio run may be extended beyond Dec. 9, Latourelle says; the troupe's next engagement isn't until February in Brussels, Belgium.)

With Latourelle's Cirque background, it's no surprise that "Cavalia" includes elaborate multimedia presentations featuring ethereal music, dramatic lighting and special effects.

For example, a water curtain serves as a screen for ghostly projected images. At certain moments, soap-bubble snow -- and paper leaves -- shower down on audience members. Colorfully costumed acrobats and aerialists soar above the stage, borne aloft by wires or bungee cords.

At other times, however, "Cavalia" celebrates the bond uniting horse and human in enchantingly low-tech fashion -- as equestrian co-director Frédéric Pignon frolics with equine friends who gallop, prance, rear, roll over and bow on command, after just a touch or whisper from their two-legged companions.

"We try to show the personality of each" horse, Pignon says to explain the show's free-spirited "Liberty" sequences. "You want them to play. But you have to be able to control it."

At a "Cavalia" preview, rambunctious buckskin stallion Nacarado (known in the stalls as the show's "rock star" because of the long, lush forelock that falls into his eyes) exemplifies that playfulness, kicking up his heels in a game of try-and-catch-me before lying down to roll around in the dirt -- and revel in his freedom.

"You never have the same show," Pignon acknowledges. "Every day it's different."

Especially when the show's sequences include demonstrations of various equestrian arts, from dressage to Roman riding, where riders stand astride two-horse teams racing around the stage -- while acrobats leap and tumble in their midst.

The combination of humans and horses leads, inevitably, to unpredictability. And that unpredictability, Latourelle says, makes "Cavalia" more challenging to stage than a humans-only production.

"It takes much more time with horses," he says, noting that one minute of the show "takes at least 10 hours of work" with "Cavalia's" equine performers.

Throughout, the show is "following the timing of the horses," he adds. "They're the ones who tell us when we can move."

For "Cavalia" audiences who'd like to get up close and personal with the show -- and its four-legged stars -- a special "Rendez-Vous" package (priced at $115 for children 12 and under and $195 for adults) includes, in addition to the show, souvenirs and refreshments and a behind-the-scenes tour of the "Cavalia" stables.

There, visitors can watch the horses in their stalls while grooms braid their manes after the show (that accounts for their wavy onstage look), or observe them in the outdoor paddock, basking in the desert sun. (It's a big improvement, weather-wise, from the show's previous tour stop: Montreal.)

In the past three years, "Cavalia" has toured from coast to coast, performing more than 700 shows for more than a million people.

Those audiences saw a show that ran more than two hours, including an intermission. In Las Vegas, "Cavalia" runs about 90 minutes without a break.

It's in the same venue, however: a 2,000-seat auditorium set up under a circus-style big top with a stage 160 feet wide.

"The horses needed 160 feet to run at full speed," Latourelle explains. "For the horses, the stage is their playground."