"Ice Age: Dawn of the Dinosaurs": Pegg gives a boost to long-in-the-tooth franchise

While it's nice to hear Ray Romano, Denis Leary and John Leguizamo once again voice the comical lead characters in "Ice Age: Dawn of the Dinosaurs," this third entry in the animated series about prehistoric animal pals adds fresh energy with the addition of Simon Pegg to the vocal cast.

Pegg, who was so much fun as the Enterprise's exuberant engineer Montgomery Scott in "Star Trek," is equally at home in "Dinosaurs" as Buck, a half-deranged weasel. His arrival as a madcap hero somewhat offsets the film's perhaps-inevitable staidness, though the 3-D presentation helps, too, by adding a little visual excitement.

"Ice Age" (2002) and "Ice Age: The Meltdown" (2006) concerned the unlikely bonding of wary woolly mammoth Manny (Ray Romano), cynical saber-toothed tiger Diego (Leary) and scatterbrained sloth Sid (Leguizamo) over bold acts of altruism set against deadly climate change. But the new movie begins more like a threadbare, domestic sitcom out of 1950s television.

We find Manny and his mate, Ellie (Queen Latifah), in a family way and nesting like crazy. Their bliss chafes against Diego's natural restlessness, while Sid's own hankering to be a parent results in an impulsive appropriation of three dinosaur eggs found in a cave.

An irritated T-Rex mom carts Sid off, along with her triplets, to a tropical, lost world beneath the familiar snow and glaciers of "Ice Age." Manny, Diego and Ellie mount a rescue, meeting an unexpected ally in the vine-swinging Buck, the only mammal in a Jules Verne-like underground world where dinosaurs exist long past their supposed demise. ("I liked you better when you were extinct," the scoffing Manny says to one of the great beasts.)

Brave but nuts, Buck leads the motley herd through dangerous terrain, and Pegg has a field day with the character's wild abandon. So good is the British actor's performance, it's actually hard not to be moved by Buck's revenge-laced, Captain Ahab-like attachment to a giant dinosaur that blinded him in one eye.

Still, even Pegg's participation doesn't help justify "Dinosaurs," which strains to keep the "Ice Age" franchise going despite exhaustion of the original environmental theme. Even new scenes involving the once-hilarious Scrat, the hapless critter who can't hold onto an acorn, feel worn out. That's when you know it's time to go.

Tom Keogh: tomwkeogh@yahoo.com