Movies where humans and animals converse are a bad idea in principle, and Kevin James’ “Zookeeper” is not here to prove that interspecies ensembles have simply been a misunderstood, underappreciated sub-genre.

“Zookeeper” is as dumb as they come, the movie that finally allows Adam Sandler to lend annoying voice to a Capuchin monkey as it talks incessantly about flinging poop around.

James is dopily likable as the title guy able to commune with his critters. Yet his character and the other humans are so thinly drawn that a melancholy gorilla voiced by Nick Nolte shows more personality and comes off as the movie’s highest primate.

A conscientious animal tender at the Boston zoo, James’ Griffin Keyes is a loser in human relations, still stinging over the way love-of-his-life Stephanie (Leslie Bibb) scorned his elaborate marriage proposal five years earlier.

After Stephanie reappears, Griffin’s old feelings return, and the lions and monkeys and bears that adore him take pity and break the code of the wild — never talk to humans.

They reveal that they’re able to speak in a variety of famous Hollywood players’ voices — Cher, Nolte, Sylvester Stallone, Jon Favreau. And for good measure, Sandler as the monkey seems to be aiming for a screechy impersonation of Gilbert Gottfried, in case that’s something you’ve been dying to hear.

Fearful their faithful zookeeper might fly the coop for a cooler job to impress Stephanie, the animals coach Griffin in the to help him win her back.

So we get to see James strutting and rolling around like a bear, urinating to mark his territory and otherwise behaving in ways that would make his romantic prey declare him a psychotic and seek a restraining order.

Yet some of Griffin’s animal antics work their charms not only on Stephanie, but also on gorgeous zoo veterinarian Kate (Rosario Dawson). The filmmakers at least should have given Dawson a pair of dorky glasses to explain why Griffin somehow failed to rut after her all these years.

Nolte wisely just talks like himself, and his gruff rumble sounds right for Bernie the gorilla, a noble, lonely ape in solitary confinement because of a ruckus with a cruel zoo tender (Donnie Wahlberg).

A few laughs arise out of the weird friendship Griffin forges with Bernie.

As he did in “Paul Blart: Mall Cop” and “Chuck and Larry,” James hurls himself into this sad scenario with energy and teddy-bear charm that makes him impossible to hate. But it’s easy to hate “Zookeeper.”

If we could talk to the animals, they’d probably hate it, too.