Eyelash Pit Viper

Thanks for the comments guys! It's true, that they won't move for days if they like their spot. This particular one was in this exact spot for at least two days. As I get the rest of the Costa Rica pictures up (it won't be for a while, I'm leaving for Panama on Thursday), you'll see not only the greenish-grayish color morphs, but they also come in gold, brown, and even white color phases!

Oh yeah, there are certainly pit vipers that carry deadly hemotoxins, this species however is not lethal under most circumstances. Wouldn't want to meet a bamboo viper off guard...

Ashish, although these guys are venomous, a bite from this species would not be deadly unless it hit a major artery or went untreated. Still wouldn't want to get bitten though!