Ice Age: Continental Drift, the fourth installment in the Ice Age cartoon franchise, is amusing but never rousing. The essentialness of the herd - be it blood-based or one of your own choosing - is the film's clarion call. That lesson was first learned in the series' opening salvo, when the dour Manny the Mammoth (voiced by Ray Romano) found unlikely companionship with Sid the Sloth (John Leguizamo) and Diego (Denis Leary), a saber-toothed tiger tamed by fraternal bonds.
Over the course of the series, they've picked up new pals; Manny now has a wife and child. When continental divide sunders Manny, Sid and Diego from their herd, setting them adrift at sea, they must claw their way back to dear ones on dry land who are themselves marching toward a land bridge as the crumbling ice shelf they once called home nips at their heels.
A colorful spectacle with breathtaking line detail, Ice Age: Continental Drift looks terrific. New voices - if not particularly fresh characterizations - include Peter Dinklage's simian baddie, Captain Gutt; Jennifer Lopez's growling first mate, Shera; and Wanda Sykes' turn as Sid's demented Granny, working an old-biddy bark to reliable comic effect. Sykes is a welcome addition, but still: The party's gone on too long.
Is it that the film's wink-wink disregard of historical continuity has gone stale? (The last installment was set during dinosaur times.) Or that it positions a yellow-toothed buccaneer ape as its antagonist? (Pirates are so mid-Aughties.) Or that it is about one more end-times scenario in a summer already sputtering with catastrophe exhaust? Yes on all counts, but the biggest disappointment may be that the filmmakers have found no new thematic ground to tread.