This third installment of the “Ice Age” series has all the obligatory touches: sharp animation, cutesy characters, prehistoric perils, dinosaur knockoffs to dazzle kids and clumsy one-liners to amuse adults.

Unfortunately, it all becomes such a mish-mash that it only assists the slow deterioration of the trilogy. The usual voice-over characters are along for the ride as woolly mammoth Manny (Ray Romano) and mate Ellie (Queen Latifah) exult in impending parenthood while sloth Sid (John Leguizamo) saber-toothed tiger Diego (Denis Leary) and possum pair Crash (Seann William Scott) and Eddie (Josh Peck) feel left out among the dwindling herd.

The only breath of fresh air is Simon Pegg (“Shaun of the Dead”) as crazed weasel Buck. Deliriously obsessed with survival in a subterranean, glacial world occupied by dinosaurs, Buck becomes the ringleader when the gang ventures into the abyss to search for Sid, who, feeling pangs of parenthood himself, has taken to mothering three dinosaur eggs he discovers.

If it didn’t get so sappy along the way - replete with a superfluous subplot love story of two squirrels chasing an acorn through the depths of icy caverns - it would be more entertaining, at least for adults.

And that adds to the oddity of this trilogy. Though they seem tailored to children, all three are rated PG-13 due to the scare factor of ominous dinosaurs, overall peril and mildly crude humor. Fox would be better off toning it down or ratcheting it up, rather than trying to straddle the line. In the case of “Dawn of the Dinosaurs,” the question is: Who’s going to get bored faster - the kids or the parents?

Also available Tuesday: “Il Divo” (MPI, $27.98, Blu-ray $34.98); “On the Road With Charles Kuralt” (Acorn Media, $39.99), with featurettes; and “Orphan” (Warner, $28.98, Blu-ray $35.99), with featurette, deleted scenes, digital copy and alternate ending.