Photos by joelsartore | Heller’s red-necked keelbacks are both venomous and poisonous. While venom comes from their fangs, poison comes from specialized glands called nuchal glands. These neck glands store toxins, especially bufadienolides sequestered from eating toads, which the snake releases through skin rupture when threatened. Photos taken in the Czech Republic. To see more species featured in the Photo Ark, follow me joelsartore. #PhotoArk