There are more than 3000 species of snakes on Earth, ranging from the at roughly 10 cm long (about the same as a deck of cards) to the at around 6 m in length (almost as tall as an adult male giraffe!). Luckily, only about 600 are venomous, and only around 200 are venomous enough to seriously harm or kill a human.
Despite the existence of hundreds of venoms, nearly all snake venoms fall into one of three categories, depending on how they affect us: neurotoxins, cytotoxins or myotoxins.
Neurotoxins are common to the Elapidae family of snakes, which include cobras, mambas, coral snakes, and copperheads. They work on the nervous system by disrupting the electrical impulses that our nerves and muscles use to function.
Neurotoxins can mess with our neurons in a few different ways. Imagine your neurons like a lamp plugged into an electrical socket. For the lamp to function normally, it should be able to turn on and off at different times. With 伪-neurotoxins, it鈥檚 as if someone put a babyproof cover on the socket, preventing us from plugging our lamp in at all. The result? No light. On the other hand, with dendrotoxins, the lamp is plugged in, but no electricity flows from the socket to our lamp. Again, no light. But with fasciculins, it鈥檚 like the lamp鈥檚 plug is stuck in the wall. Constantly activated with no off switch, even though we want to go to bed.
Vipers favour the use of cytotoxins鈥攙enoms that directly damage cells. Some common types include phospholipases, which disrupt cell walls, and hemotoxins, which affect the circulatory system. Some hemotoxins trigger the destruction of red blood cells, while others affect the clotting factor of blood鈥攅ither by making blood too clotted and thick to flow or too thin to ever clot and stop external bleeding.
Myotoxins are less common in serpent physiology but are found in certain species of rattlesnakes. They contain basic peptides (chains of amino acids too short to be considered proteins) that directly disrupt the flow of charged molecules our muscles rely on to contract.
With such a wide range of venom types and mechanisms of action, it鈥檚 no surprise that nearly every snake species needs a tailor-made antivenom. Luckily, Canada only has native species of venomous snakes.
Nonetheless, it can be pretty tricky to identify snakes reliably in the wild. So, if you鈥檙e ever on the receiving end of a snake bite, seek medical attention immediately! Do not try to catch the snake to bring with you鈥攕ome help for your doctors in identifying your attacker is not worth a second (or third, or fourth) bite.
