The law of diminishing returns is ruthlessly validated by Ice Age: Dawn of the Dinosaurs, the third and sadly anaemic instalment in a once vigorous cartoon franchise. Whereas the previous chapters were sweetly anarchic, full of wisecracks and narrative digressions but also curious about eco-issues such as global warming and the extinction of species, this effort is dramatically inert and uninspired.

The characters, naturally, are the same, and include Manny (voiced by Ray Romano) the droll mammoth, Sid (John Leguizamo) the cowardly sloth and Scratte (Karen Disher), the acorn-obsessed squirrel. The plot too is lifted untouched from the previous outings, and involves a reluctant and yet incredible journey. Here, however, all pretensions towards real-world topics are jettisoned in favour of the preposterous discovery, by Sid, of an entire community of dinosaurs, complete with active volcanoes and thriving eco-system, living just below the surface of the ice. Which, clearly, makes no sense other than to allow for an agonising musical montage set to the 1987 hit by Was (Not Was), Walk the Dinosaur.

The threadbare narrative essentially involves the rescue of Sid who, after briefly fostering three T. Rex babies, has been kidnapped by their angry mother. Manny and his heavily pregnant partner Ellie (Queen Latifah) are sent in hot pursuit and strangely give the movie plenty of time to discuss the perils of impending parenthood. Indeed, for a children’s film Dawn of the Dinosaurs seems oddly preoccupied, like an anti-teen pregnancy campaign, with underscoring the responsibilities of child-rearing. “Being a parent is a lot more work than I thought,” Sid says archly. “Maybe I’m not ready.”

Otherwise the movie, showing in 3-D where available, is merely a depressing indication of how that format is increasingly resistant to storytelling and addicted to needless visual chicanery. Its six giddy “point-of-view” chases add nothing to the story and, ironically, slow it down considerably. That the most effective 3-D shot is a slowly falling leaf in the first act is missed by a movie addicted to haste and chaos rather than pace.

Finally, and honouring the Ice Age format, the leftfield adventures of Scratte the squirrel are duly littered throughout the film, and this time involve a sassy female opponent with an equally obsessive yen for acorns. They provide moments of occasionally inspired distraction. But they cannot disguise the sense of a franchise, like the mammoths themselves, on its last legs.

U, 96mins

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