Which part of their body do snakes use to inject venom?

Snake venom is highly modified saliva containing zootoxins that facilitate the immobilization and digestion of prey and defense against threats. It is injected by unique fangs during a bite, and some species are also able to spit their venom.

A fang is a long, pointed tooth. In mammals, a fang is a modified maxillary tooth, used for biting and tearing flesh. In snakes, it is a specialized tooth that is associated with a venom gland (see snake venom). Spiders also have external fangs, which are part of the chelicerae.

The glands that secrete the zootoxins are a modification of the parotid salivary glands found in other vertebrates and are usually situated on each side of the head, below and behind the eye, and encapsulated in a muscular sheath. The glands have large alveoli in which the synthesized venom is stored before being conveyed by a duct to the base of channeled or tubular fangs through which it is ejected.