Twentieth Century Fox may have shut down its animation department after such costly failures as "Titan A.E." and "Monkeybone," but its parting shot is a winner. "Ice Age," the computer-animated family film from director Chris Wedge, is a clever, pleasingly sentimental tale of prehistoric times. It may not have the cutting-edge sophistication of "Shrek" or the Pixar movies, but it's a close runner-up. Grown-ups will laugh right along with the kids; they will also be struck, as little ones may not be, by the many resemblances to other recent animated movies.

Our odd-couple heroes are a large woolly mammoth named Manfred and his pesky sidekick Sid, a slothful sloth who attaches himself to the more powerful Manny like an unwanted barnacle. Or like a certain fast-talking donkey attached himself to a popular green ogre. The ice age is commencing, and while all the other creatures migrate south, the independent-minded Manny heads north. While trying to ditch the unwanted Sid, he acquires two other unsolicited companions--an abandoned human baby, Roshan, and a saber-toothed tiger named Diego. The tiger offers to be the team's tracker as they head out on a mission to return the infant to its human family, but Diego (to mix animal metaphors) is a wolf in sheep's clothing. He's really there to kidnap the child so that his boss can have the little darling for breakfast.

If the forced migration odyssey reminds you of "Dinosaur," the spectacle of beasts determined to return a human child to its home mimics "Monsters, Inc.," and the saber-toothed tigers look as if they had broken off from the villainous herd in "The Lion King." (Wedge himself calls it "three prehistoric mammals and a baby.") While you're at it, throw in a bit of "The Searchers." The other inadvertent echo here is of the recent Winter Olympics: these creatures, in the course of their hazardous journey, manage to slalom, snowboard and bobsled their way across the Northern Hemisphere, without aid of instant replay.

The vocal casting is first rate. Ray Romano gives the gruff but goodhearted Manny a wry, long-suffering wit. (Ever notice how much his nasal, dried-syrup voice sounds like Joe Mantegna's?) John Leguizamo is a hoot as the jive Sid, whose comic timing is pure borscht belt. The duplicitous Diego, who may not be such a bad cat after all, is a perfect fit for Denis Leary's insinuating switchblade of a voice. The film's funniest creation--a monomaniacal squirrel rat whose obsession with burying a single acorn sets off an avalanche that begins the ice age--has no words at all, only squeaks, screeches and hysterical screams. He's a sort of prehistoric ancestor of the Roadrunner cartoon, and it's easy to imagine him as the star of his own series.

In the time-honored tradition of kids' films, "Ice Age" mixes broad displays of physical cruelty with a sweet message, which in this case is about the need of each member of a herd to look after the other. As a plea for multispecies diversity, "Ice Age" has a magnanimous heart, but there may be those who find its portrait of the clueless, doomed dodo birds defamatory and prehistorically incorrect. These dummies are beyond the pale. And damn funny.