CBS's Survivor may now have to begin thinking about its own survival following the premiere of Survivor: Caramoan, which on Wednesday drew the lowest ratings for a season opener since the series debuted 11 years ago. Facing competition from Fox's American Idol, Survivor attracted just 8.96 million viewers versus 10.79 million for the season opener of Survivor: One World a year ago. American Idol also saw a significant drop in its numbers as it averaged 13.37 million viewers, down from 17.9 million for the comparable week a year ago. That was still good enough to give Fox a win for the night -- among both total adults and the 18-49 age group. Whether it was good enough to meet Fox's ratings guarantees to advertisers remains a separate, and unanswered, question.