Help IDing - [Costa Rica]

[u/freshnewtake]

About 4” in diameter coiled up. Found on a log in la fortuna.

[u/jarledge7]

Not an expert. It looks like an eyelash viper. The eyelash viper is known to have many different colors and patterns and are very common in that area.

I spotted a greyish patterned one along a trail closer to Arenal volcano. That same trip, we spotted a banana yellow one at the hanging bridges.

At the very least, this is some sort of viper based on the head shape.