On the outside, children and adults flock to watch and laugh at monkeys, baboons, chimpanzees, orangutans and gorillas.
But it's what happens in the inside is that fascinates director Rachel Mayeri.
"You can actually see the family dynamics and when the alpha males display and stand up on two feet and make a lot of noise," Mayeri said during a phone interview from Claremont, Calif. "As you watch, you realize (that what they're doing) is a primitive form of theatre."
Mayeri, whose film "Primate Cinema: Apes As Family," which is part of the 2013 Sundance Film Festival New Frontier Shorts Competition, expands on that concept and explores the idea of "since the closest primate relative to humans are chimpanzees, what would a film made expressly for chimps look like?"
"Strangely enough, this seemed like the most natural thing for me to do," Mayeri said. "For the past five years or so, I have been making films about primates and the media.
"I also thought about how the species are similar or different than other primates and how they are represented in feature film and documentaries," she said. "Having dealt with media representations of primates, it was time to make a movie for non-human primates as an audience."
With a grant from the Welcome Trust and other organizations, Mayeri began making films that would be shown to primates those lower down the evolutionary tree - squirrel monkeys and baboons.
"They are a much more difficult audience to figure out than chimpanzees," she said with a laugh. "I hope to work my way up the ladder to make a film for human beings."
The film she made for chimpanzees actually started as a two-channel video installation.
"You could watch the movie I made for the chimps on one side and then see the reaction of the chimps to the movie on the other side," she said.
Part of the process involved traveling to Scotland's Edinburgh Zoo to work with the chimpanzee audience to see what kind of films they liked.
"We tested out a bunch of different genres and I filmed human actors in an animatronic chimp suits acting out all sorts of primate politics," Mayeri said.
She showed them cooking shows, nature documentaries, people in costumes, people playing kettle drums and the children's program 'The Teletubbies."
"They loved 'Teletubbies' and the drums," Mayeri said. "They also liked seeing people taking masks off."
From those tests, Mayeri wrote a script that had more of the theatrical aspects of primate life.
"It started as a 20-minute film and then I whittled it down linearly for a human audience," she said. "As a visual artist, I couldn't have imagined such a challenge as to make a film that would stimulate a chimpanzee's mind and have that film triangulate in a way to show us what chimpanzees are like.
"My thoughts were, if we and they could appreciate a film at the same time, we could learn something about what we have in common," she said. "At least that was the theory."
The film's producer Matt Johnstone said humans are fascinated with primates because the species are close in the evolutionary chain.
"I feel the film is a reflection of humanity through primates," Johnstone said. "I look at it as being a mirror for humans to look our ourselves through the prism of our ancestors and cinema and helps us see who are we in a existential and metaphysical sense."
While Mayeri agrees, she also said she made the film out of love for the animals.
"They are endangered and so, fascinating, beautiful and sensitive. I hope there is something in the film that gives people something to think about."
"Primate Cinema: Apes as Family" is part of the New Frontier Shorts program that will screen today, Jan. 19, at the Redstone Cinema 1 at 9:30 p.m., Sunday, Jan. 20, at the Broadway Centre Cinemas in Salt Lake City, at 6 p.m., Tuesday, Jan. 22, at the Yarrow Hotel Theatre at 3 p.m. and on Saturday, Jan. 26, the Holiday Village Cinema at 6:15 p.m. For more information, visit www.sundance.org/festival