Madre Selva field Station, Maynas, Depto Loreto, Peru. January 14, 2011.
A rather plain-looking specimen, but what it lacked in beauty, it more than made up for in feisty behavior. The long, bird-catching teeth do a good job of slashing the fingers of the unwary (see photo below). Along with some other species, bird snakes have a physical adaption that allows them to inflate their necks and exaggerate their appearance. Formerly Pseustes poecilonotus polylepis.
My Flickr album for this species is here.