Overview
Viperidae (クサリヘビ科) are a family of venomous snakes. In Japan, pit vipers and habu belong to this family.
They live in a wide range of habitats, adapting to a variety of environments, including frigid zones, the tropics, and deserts.
Most of their venom is hemorrhagic, but some species are neurotoxic as well. Some people may have been taught that snakes with triangular heads are dangerous because they have large venom glands on their cheeks.
The fangs are quite long, and when the mouth is closed, they fold up at the base and retract into the mouth.