Saving Who-ville is a big production

What distinguishes Horton Hears a Who! from the other recent Dr Seuss film adaptations - How the Grinch Stole Christmas and The Cat in the Hat, in case you need reminding - is that it is not one of the worst movies ever made. That's faint praise, I know, and I'm even willing to go a bit further. There are aspects of Horton, directed by Jimmy Hayward and Steve Martino under the auspices of the 20th Century Fox animation unit responsible for the Ice Age movies, that are fresh and enjoyable, and bits that will gratify even a dogmatic and orthodox Seussian.

Unlike The Grinch and The Cat, Horton does not try to flesh out the good doctor's graphical world by means of sets, prosthetic makeup and the other accouterments of live-action moviemaking. The animation is free, supple and brightly colored, and the crazy curves and angles that Seuss arranged on the page pop into three dimensions with rubbery energy and elastic wit. Who-ville in particular - that speck-borne town with its spindly machinery and gravity-defying architecture - is a wondrously kinetic place. And the Jungle of Nool, where Horton passes his time and fights for survival of the Whos, is appropriately lush, inviting and strange.

But if Horton Hears a Who! offers a showcase of the visual inventiveness and technical flair that characterizes Hollywood-financed children's animation these days, it also shows some of the limitations of the computer-animation, talking-animal genre. The filmmakers revel in the imaginative freedom their image-making technology affords, and use it with self-confidence and flair, especially in action sequences. (A chase through a field of bright pink clover is lovely and thrilling.)

When it comes to telling the story, however, and drawing out the dimensions of the characters, this Horton supplements Dr Seuss's fable with pages from the battered, worn-out Hollywood family-film playbook.

GOING THROUGH THE MOTIONS

All kinds of extraneous elements are added to the story. The Mayor of Who-ville, voiced by Steve Carell, is a beleaguered dad who has trouble communicating with his son, a moody emo boy named Jo-Jo. The problem with this father-son reconciliation narrative is not that it is un-Seussian - though such intergenerational melodrama almost never figured in Dr Seuss' work - but that it's tired and sentimental. You don't get the sense that the writers (Ken Daurio and Cinco Paul) actually believe in it. It just feels like something they know they're supposed to do.

The excitable sidekick is another such requirement, and here that duty is taken on by Seth Rogen in the role of Morton, a motor-mouthed mouse who is Horton's best friend. Rogen's casting, like Carell's, is less a stunt than a kind of pop-culture insurance clause. Get some box-office-proven comedians to do the voice work - Jonah Hill, Isla Fisher and Dan Fogler make up part of the B team here, in smaller parts - and you can't fail.

And Horton Hears a Who! probably won't, at least as a commercial proposition. But the star whose presence is clearly meant to be its gold-plated guarantee of success - Jim Carrey as Horton - is also the source of its most egregious failure. Carrey, who also played the Grinch, can be an agile and restrained actor when the mood strikes him. But the steadfast elephant is a vehicle for an endless, grating avalanche of clowning and riffing. Carrey not only breaks character with his goofing, he also all but destroys the nobility and sweetness that make Horton such a durable hero of children's literature.