Horton may hear a Who, but the rest of us may hear a lot of hoopla, and it’s not all the charming sort you expect from a benign Seussian world.

“Dr. Seuss’ Horton Hears a Who!” succeeds to a point in putting the Hollywood spin on Theodor S. Geisel’s beloved children’s book about an elephant defending a microscopic civilization.

Very young children will find plenty to giggle over in the manic slapstick of this latest computer-animated adventure from Blue Sky Studios, the outfit behind the “Ice Age” flicks. And Blue Sky’s creations are a solid transmutation of Seuss’ odd storybook world into digital images. Seuss’ rhymes generally give way to loud pratfall nonsense, though, as the filmmakers stretch a thin, thin story to fit a feature-length movie.

The result is more amiable than the live-action “Dr. Seuss’ How the Grinch Stole Christmas” starring Jim Carrey, who returns to Who-Ville this time as the voice of Horton the elephant. And “Horton” is a huge leap beyond the atrocious live-action “The Cat in the Hat” with Mike Myers.

All three Seuss renderings share a common problem: The padding needed to take them to the big screen diminish the story, leaving more to gawk at but less to savor.

Computer-animation veterans Jimmy Hayward and Steve Martino, both making their directing debuts, quickly establish the colorful, carefree life in the jungle of Nool, where the happy Horton co-exists with a menagerie of strange critters.

His buddies include the gabby mouse Morton (Seth Rogen), while the creatures of Nool live under the thumb of the self-righteous Kangaroo (Carol Burnett), the snooty equivalent of a small-minded PTA mom.

Horton incurs the wrath and ridicule of Kangaroo as he insists he’s made an astonishing discovery – an endangered land called Who-Ville that exists in a tiny speck resting on a clover.

Kangaroo maintains that if you can’t see something, it can’t exist, forcing Horton to sneak about in communicating with the mayor of Who-Ville (Steve Carell), as the elephant seeks a haven for the tiny town safe from predators and other dangers.

While Carrey and Carell do a lot of jabbering, the voice cast – which also includes Jaime Pressly, Jonah Hill and husband and wife Will Arnett and Amy Poehler – sounds fairly plain and anonymous.

The exception is Charles Osgood, who brings his folksiest manner as narrator, offering up soothing snippets of Seuss’ rhymes.

Screenwriters Cinco Paul and Ken Daurio, whose credits include “The Santa Clause 2” and “College Road Trip,” fill in the gaps around Osgood’s homey narration mostly with frantic, forgettable patter.

There was barely material enough for the 1970 half-hour TV version of “Horton Hears a Who!” so imagine the stretching and stuffing that went into this. Everything Horton does drags on rather tediously.

Still, the animation itself is vibrant, occasionally dazzling, loaded with detail that helps bring the whimsy of Seuss’ world to life. And there’s Seuss’ moral – that a “person’s a person no matter how small.”