Last night, in honor of my dad’s birthday and the 3 happy weeks he spent in high school reading Tolkien (and not doing much else), we went to the Imax to see The Hobbit. Despite seeing all of one foot, nostril and eye, Smaug stole the show for me. Though those shaggy ponies were a close second and I disapprove of excessive burninating, I have a soft spot in my heart for all things scaly. Especially if they’re dragons. Dragons dragons dragons. This is probably why snakes and the less derpy lizards hold such a fascination for me. Some kids had imaginary friends in grade school, I had an imaginary King Cobra named Spike.
Fast forward to undergraduate senior thesis and I discovered that the awesomeness of the ophidians was not limited to their stupidly vast variety of species. They, dare I say it, have some bitchin’ chemical compounds at their disposal. I am of course referring to snake venom, though as I pointed out in my previous post (https://dailyscienceblog.wordpress.com/2013/01/19/eau-de-my-thesis/), pheromones have a lot to bring to the table as well. Lord knows what kind of table, but if there are snakes involved, I am THERE.
It is easy to write off venom from any animal, be it snake, scorpion or platypus, as death and/or pain juice. Nasty stuff, sure, but venom produced by a given animal is specific to that animal’s needs. To clarify, venom is injected via bite or sting while poison is consumed. Both contain harmful chemicals, toxins. Venom components are largely proteins that perform a variety of functions, including immobilization, rapid death, necrosis, tracking and defense. Let me stop you before you look up necrosis and scar yourself for life: necrotizing venom rots tissue and assists in the “pre-digestion” of prey. Spiders like it, pit vipers like it, we DON’T. But it’s a great/gross example of how certain components have overlapping functions in the same or different species; necrotoxins assist in pre-digestion for brown recluse spiders, and provide powerful defensive bite; vampire bats need an anti-coagulant (chemical that prevents blood-clotting) in order to feed, but certain snakes use a heavier dose in their venom to provoke rapid death by hemorrhage; and immobilizing neurotoxins may merely hinder (allowing other toxins or offensive means to kill), or immobilize to the point of respiratory failure as occurs from TTX (pufferfish) venom. Toxins involved in defensive envenomation run the gamut and results range from the mild stings of bees and platypi, to the bullet-like stab of the tarantula hawk wasp to the lethal bites of black widows and mambas. This is because, except for perhaps the non-predatorial bees and the playpi, defensive stings and bites are not specialized and use the same toxins as those used in prey capture. Makes sense, right? Tracking components, which allow snakes to retrieve prey released following envenomation and avoid injuries sustained from tackling their dinner, are the only truly specialized part of venom.
Now that I have everyone thinking of how venomous snakes and assorted creepy crawlies can kill you, here are some numbers to drive home the point: in the world there are an upwards of 100,000 known venomous species (that include insects, arachnids, jellies, anenomes, snails, fish, reptiles, fleas and ticks), those species together possess an arsenal of over 20,000,000 toxins, of those 10,000 are known to science and 1,000 of those are studied in depth. Before you succumb to the warm fuzzies (or seizures of terror), I have a few more numbers. Those thousand toxins studied have provided us with over a dozen diagnostic tools and 20 drugs, some of which use toxin dosages that dance a fine Conga line between useless and deadly. Consider: Russel’s viper can kill you, but a derivative of its venom is used to measure clotting time in lupus patients; type 2 diabetics can thank the gila monster for their toxin that stimulates insulin production in the pancreas; viper venom anticoagulants have been around since the late sixties; and Brazilian pit vipers spawned the ACE inhibitor class of drugs used in battling hypertension. Much more is in the works, such as the cancer cell tag derived from deathstalker scorpions that could cut down the size of detectable tumors from a billion cells to a couple hundred. Effectively researched, the medicinal possibilities are endless. So they may not spew fire or fly, but snakes (and their less dragon-like, venomous compatriots) hold some downright mystical proteins in their jaws.
See? Black mamba is smiling, he just wants to say hi.
Source
Kardong, K. V. 2002. Colubrid Snakes and Duvernoy’s “Venom” Glands. Journal of Toxicology. 21.1 & 2: 1-19.
Holland, Jennifer S. Feb 2013. “The Bite that Heals”. National Geographic. 223: 64-83.
Photo credits me, komodo dragon credit Woodland Park Zoo, black mamba credit Monroe Reptile Zoo.
Daily Science (blog) 