EMPEROR penguins may struggle to stand shoulder to shoulder with Hollywood's Alist, but their diminutive stature has done nothing to dim their prowess on the big screen.

The surprise stars of this summer's crop of films are a colony of emperor penguins whose 70-mile trek through the Antarctic has exerted a magnetic pull on US audiences.

A month after March of the Penguins opened in four theatres in New York and Los Angeles, the documentary by Luc Jacquet, 37, a French biologist, has broken into the US top 10, squaring up to multimillion-dollar blockbusters such as Batman Begins and the Fantastic Four.

To the delight of its distributors, critics have heaped lavish praise on the film's feel-good narrative.

Some have even cited its success, which follows the breakthrough of documentaries such as Michael Moore's Fahrenheit 9/11 and Morgan Spurlock's Super Size Me into the mainstream, as continued evidence of the weakness of Hollywood's traditional output.

Hannah McGill, The Herald's film critic, said: "There's been a huge increase in the commercial viability of documentaries and that's one of the best things to happen in cinema in the past few years.

"It's heartening that people going to see these factual films can establish a basic emotional connection which gives them something to hold on to, which they don't get in most Hollywood special-effects bonanzas.

"You can't go wrong with penguins. Everyone loves a good nature documentary."

The story, narrated by Morgan Freeman, follows the penguins' annual trek from the sea to their breeding grounds on the ice.

It displays their fortitude and fierce loyalty to their mates, with whom they are monogamous for one breeding season.

In its opening weeks, the film grossed a bigger turnover per screen than any other, including War of the Worlds, Steven Spielberg's big budget epic.

Michael Rosove, a San Diego doctor who has written two books on the Antarctic, claimed the penguins' appeal was in caricaturing human behaviour.

"They do things we do but only if we let our guard down.

They are funny to watch. They make us laugh at ourselves, " he said.