Hydrodynastes gigas and Snake-Bite Physiology

Marcio Lisa Photograph

Hydrodynastes gigas, also known as the false water cobra and the Brazilian smooth snake, is a species of snake that inhabits the Pantanal, as well as other tropical wetlands in South America.  I want to write about it because I am instinctively afraid of snakes and salamanders, but am also fascinated by them.

H. gigas is interesting/perfect fodder for nightmares because it can swim, is well camouflaged, and venomous.   Worse/better yet, it can reach 9-10ft long.  It is active during the day and believed to be highly intelligent.  Unfortunately for its scariness-level, its bite is not fatal to humans.  Although the venom is powerful, it is produced only in very small quantities.  The mechanical damage inflicted by its teeth is usually more dangerous than the venom, which causes hypersensitivity, pain, itching, excessive swelling, and bruising.

Luckily, if one of its fangs gets too old or breaks off, a new one will grow in and replace it.  For most snakes, the new fang "locks" into place, attaching so that the venom glands squeeze the poison out.  The venom travels through the groove in the fang and into the open wound.  Unlike vipers (such as the South American rattlesnake, another Pantanal inhabitant) H. gigas has rear fangs, which are smaller, less mobile, and in the back of the mouth.  In the case of H. gigas, venom comes from the Duvernoy's gland.
(click here for more about snake fangs)