Ice Age 3, Carlos Saldanha, 96 mins, (U)Am I Black Enough for You, Goran Hugo Olsson, 87 mins, (12A)

The third Ice Age movie subjects its child viewers to too many grown-up themes before the fun starts

I can't believe that many eight-year-olds worry about how good they'll be as parents, or if they'll lose touch with their friends once they have families of their own.

But the makers of children's films persist in foisting those issues on us, Ice Age 3 being the latest example. Ellie the mammoth is about to have a junior mammoth, so her husband Manny is getting antsy, while Diego the sabre-toothed tiger and Sid the sloth are afraid they might have to find some other mammoths to hang around with. Does that sound like the starting point of a timeless kids' cartoon to you? Presumably Ice Age 4 will grapple with such toddler-friendly themes as mortgages, pensions and male-pattern baldness.

In the meantime, Ice Age 3's tediously talky opening has the characters plodding around a dull white landscape, airing their neuroses, and giving the viewer ample time to ponder whether anyone wanted an Ice Age threequel anyway. Let's be honest, Diego and Manny have never caught on in the way Buzz Lightyear and Shrek did, and even the franchise's vaunted silent comedy interludes, in which a manic rodent forever fails to get his paws on an acorn, are wearing thin.

Fortunately, the film's early scenes seem to have been designed specifically to make what follows seem better. Having crossed a bridge made of a tyrannosaur skeleton and encountered a weasel voiced by Simon Pegg (both promising signs), the mixed-species herd descends into a lost world far beneath the earth's surface where dinosaurs have yet to die out.

Yes, it's a cartoon about some prehistoric animals discovering some even-more-prehistoric animals. But as contrived as this premise is, there's no denying that the towering dinosaurs are a rainbow-coloured treat compared to Manny and his fellow furry nobodies, and the subterranean tropical wonderland is a dazzling respite from the first half hour's glaciers and pine trees. It's still not a classic cartoon.

Instead of bothering with a plot, the screenwriters have devised enough fast and furious set-pieces to furnish a video game and a theme-park ride, and then glued them together with the pun-heavy babblings of a cast which consists almost solely of wacky sidekicks. Still, it's nowhere near as humdrum as Ice Age 2, and parents can take comfort in the knowledge that it gets more entertaining as it goes along. By the time it reaches the cracking final action sequence, which is especially dizzying in digital 3D, my resistance to Ice Age had thawed.

Am I Black Enough for You is an unfocused, hotchpotch of a documentary, but there are a few shining nuggets in there which hint at how fascinating it might have been. Its subject is the angel-voiced Billy Paul, a Philadelphia soul singer best known for 1972's Grammy-winning US No 1 "Me and Mrs Jones". Paul contends that his follow-up single, "Am I Black Enough for You", alienated mainstream audiences, and he blames the record's writer-producers, Gamble & Huff, for the decision to release such a controversial track. It's a novel inversion of the music-industry norm to have a singer who wanted commercial success being confounded by the executives' insistence on more challenging and political material, and that's not the only twist in Paul's tale.

Another is that he's been married to the same woman for four decades, despite a period of debilitating drug addiction. Poignantly, he was inspired to clean up when he was listening to the radio, and he heard "Man in the Mirror" by Michael Jackson.