As computer animation makes the move from novelty to norm, it's only natural that a few familiar elements should emerge. To name a few: sentiment, pop-culture send-ups, characters who hide their affection for one another under layers of snark, and drawn-out setpieces virtually unimaginable in the field of conventional animation. Ice Age, a first stab at feature-length computer animation from Fox and director Chris Wedge, attempts to combine all of the above in a package not quite big enough for the cargo. Providing most of the sentiment, Ray Romano supplies the voice of a watery-eyed wooly mammoth named Manfred, a character largely inspired by John Wayne's lost-soul protagonist in The Searchers. Wandering disconsolately against the tide of migration, Romano picks up unwanted sidekicks in the form of an abandoned sloth (John Leguizamo) and, a bit later, a human toddler. After Leguizamo talks the reluctant Romano into returning the baby to its human tribe, they're joined by a sabertooth tiger (Denis Leary) with dubious motives and a soft spot the size of a glacier. The film looks great, but it only intermittently measures up to its Monsters, Inc.-with-metafauna potential. Better jokes might have redeemed its obvious plot, but instead of stuffing their film with clever moments, Wedge and his writers aimed the majority of the gags at the younger end of their potential audience. The result is a handful of poop jokes and lots of mugging from Leguizamo's sloth. Even the smarter gags, like the flock of survival-impaired dodos, depend on sight gags that are precision-timed but never particularly funny. Kids won't mind a bit, but adults accustomed to Shrek and Pixar will have no trouble spotting what's missing.