A monster movie with a message

For no other reason than to draw in the torture crowd, they're selling "Primeval" as a serial-killer thriller, heavy on the gore. In fact, it's something more interestingly bizarre, if not actually good: a cross between "Jaws" and "The Constant Gardener."

That's right, the crusading Afrocentric agit-entertainment of "Blood Diamond" and "Catch a Fire" has percolated down to Z-grade monster movies. No surprise, the monster movie wins, but not without a fight.

The mass murderer of the movie's trailer turns out to be a 25-foot crocodile that has terrorized the waters of northern Burundi and Lake Tanganyika for decades. The locals call him Gustave and he really exists -- go ahead, Google him -- although the filmmakers have relied on a computer-animated beastie instead. Gustave probably doesn't take direction well. Plus he's hell on the extras.

An American news crew descends on the area to capture the giant and bring him back alive, dropping into a raging civil war between Hutu and Tutsi. The producer is the macho Tim (Dominic Purcell of TV's "Prison Break"), the on-air talent the earnest and bimbotic Aviva (Brooke Langton, "Melrose Place"), the cameraman/comic relief played gratingly by Orlando Jones.

There's Jürgen Prochnow ("Das Boot"), once again in deep water in the Robert Shaw croc-hunter role. The less said about Gideon Emery as a wildlife adventurer in the unfortunate mold of the late Steve Irwin, the better.

It soon becomes a toss-up as to who's the greater threat to these babes in the lake: Gustave or the minions of warlord Little Gustave (Dumisani Mbebe), whose rep is almost as bloody as his namesake's. The cameraman accidentally videotapes an execution, and the Americans take in a local (Gabriel Malema) hoping to flee to the states.

They also discuss issues of media responsibility and American awareness of African suffering in the dumbed-down language of late-night cable junk. "The more you help, the worse it gets," growls Tim. "Oh well, it doesn't mean you shouldn't try," chirps Aviva, although she clearly cares more for a stray puppy than any humans in sight.

Then it's off to a violent near-rape in which the heroine conveniently loses her shirt, followed by more rampaging appearances by Gustave. The croc-hunter describes his favorite bait as a mixture of "blood, urine, and pheromones," which really isn't a bad review of the film itself.

"Primeval" is a hoot if you're in the mood, though, and it gets points for trying to stuff a little globo-think into the minds of Friday night mayhem fans (who will probably rebel, since only one skull pops like a grape). In the end, broader messages get beaten down by genre. "All meat is meat," says someone here, and if that's not modern horror-movie realpolitik, I don't want to know what is.

Ty Burr can be reached at tburr@globe.com. For more on movies, go to boston.com/ae/movies/blog.