Something’s a bit fishy about this new batch of Survivor contestants. Another battle of the sexes? Less than two years after the last, back in the Amazon? Is it really that simple?

Photos and video released by CBS show that Survivor: Vanuatu’s tribes will indeed be split by gender as their contest begins. And granted, 99 percent of viewers couldn’t care less. But there’s an undercurrent of skepticism among posters on SurvivorSucks — a community with 32,000 members and one of many online watering holes for fans of the show — with some commenting that it’s unlikely executive producer Mark Burnett would do “men vs. women” again without some new twist. After all, a not-so-secret ingredient to the show’s continued success is that nearly every edition has offered a mutation of previous proceedings — an unwitting tribal swap in Africa; no food offered in Marquesas, and a random swap; allowing “captains” to choose their own teams in Thailand, along with a delayed merge; Amazon’s gender battle; Pearl Islands’ “ghosts.” Tweaking things each time out keeps players, and viewers, on their toes.

So it would seem unlikely that Vanuatu would merely be an Amazonian redux (albeit with 18, not 16, contestants). Here’s a few reasons all this seems a bit off:

– The official CBS announcement Tuesday morning on the Early Show did not even mention the male/female split, other than a brief allusion to it by guest analysts/lovebirds Rob Mariano and Amber Brkich. Compare this with the 2003 announcement that Survivor: The Amazon would be men vs. women – that spawned numerous headlines, and was the lead story in that day’s USA Today Life section. Granted, in the case of Amazon, a battle of the sexes was a new gimmick. Still, the omission is odd.

– Similarly, the official Survivor: Vanuatu Web site appears to completely avoid talk of the gender divide, with contestants’ tribal affiliations also not mentioned. There is no reason to eschew such details if the tribes’ makeup remains intact for at least several episodes.

– For the first time, the premiere episode will be two hours long, according to several reports. The first five seasons featured hour-long debuts, while recent entries Pearl Islands and The Amazon had well-received 90-minute starts. Is the 30-minute bonus due to there being 18, rather than 16, contestants? Or, as one Survivor fan speculated, is it because the premiere episode features twists, like, say, an extra challenge or a tribal changeup?

– Burnett is reality TV’s biggest creative mastermind. It seems antithetical for him to feature another men vs. women battle less than two years after Amazon – especially considering that his NBC smash The Apprentice was structured identically last spring.

– From a marketing standpoint, the move makes little sense. Battle of the sexes? Been there, done that. Such a move is unlikely to excite too many viewers, unlike the much-publicized “only the clothes on their backs” twist of Pearl Islands’ start and the, um, battle of the sexes in The Amazon. And CBS will want a strong debut in order to take full advantage of the lack of Friends on rival NBC – and to dampen the ratings flame of spin-off Joey.

– SurvivorNews, a site that always seems to know what happens ahead of schedule – including the identities of all this season’s contestants, if not their exact nicknames — hinted in weeks past at an unbalanced tribal makeup, such as a tribe featuring five men and four women, and vice-versa. The site also implied the castaways might be divided by age.

Sucksters have had other theories – for instance, that contestants might compete as same-sex tribes, but live in mixed-gender camps (or vice-versa). And others think the battle of the sexes won’t last – perhaps not even for one episode.

Whatever the case, it’s helpful to remember that before the premiere of Survivor: Thailand, CBS promotions strongly implied that that show would feature a gender gap. It didn’t happen. So don’t be surprised if the feature-length first episode of Survivor: Vanuatu begins with its tribes divided by sex — but ends with a completely different configuration.