As digital animation and 3-D technology continues to improve, it's a shame animated storytelling keeps taking steps backward. The latest "Ice Age" movie, "Dawn of the Dinosaurs," is proof of that.

　　 Mind you, this third "Ice Age" installment isn't as story-thin and half-hearted as its immediate predecessor, 2007's ironically titled "The Meltdown."

　　 But it still feels considerably less fresh than the original, 2002 hit. For one thing, it continues trying to mine jokes that weren't that funny the first time around.

　　 So it's fortunate that the movie has a very good voice cast and characters that youthful audiences, at least, have grown to love.

　　 This follow-up sees the prehistoric woolly mammoth couple Manny (voiced by Ray Romano) and Ellie (the voice of Queen Latifah) preparing to have their first child.

　　 Their saber-toothed pal, Diego (Denis Leary), is feeling a little left out. And their loopy, ground sloth friend, Sid (John Leguizamo), has now decided he wants to play 英语影评"mama" as well. He's found three apparently abandoned dinosaur eggs that are about to hatch.

　　 Once they do, Sid has his hands full with the carnivorous beasts. Worse, the trio's mother shows up and isn't happy.

　　 She drags Sid and the trio of hatchlings to an underground cavern that features a variety of supposedly extinct dinosaurs and other life-forms.

　　 The cast of characters for these films is already too jam-packed as it is. Yet the filmmakers find time to introduce a new one — a crazed, one-eyed weasel named Buck, voiced by Simon Pegg ("Star Trek"). He's a character that is best left in small doses. Instead, he becomes a dominant figure in the film's second half.

　　 And again, the filmmakers can't resist throwing in some cheap humor — of the flatulence and bodily excretion variety.

　　 As usual, the best parts of the film are those involving prehistoric squirrel Scrat (the voice of "Ice Age" co-creator Chris Wedge).

　　 Here, he becomes entangled with the female of the species, with amusing results.