Can snakes die from their own venom?

06 April 2008


A rattlesnake



After watching the TV series “Life in Cold Blood” I was wondering how the venomous snakes didn’t poison themselves when they ate their prey? I know they’re not immune to their poison because they don’t use it on each other when they fight for their territory battles for example. I know if animals like ourselves ate food that had been poisoned it would have an adverse effect on us but it doesn’t seem to on snakes. I just wondered why that was?


The reason is that the venom snakes use is a mixture of proteins. Proteins are made up of building blocks of what's called amino acids. They're the same stuff, effectively, as makes up the meat in your Sunday roast. That means that if you were to eat them - say I ate a snake and ate the poison sacks - it would go into my digestive system where my stomach acid and the enzymes in my stomach would just break down the protein, so it would fall apart and it would be harmless. Venom is only actually toxic if it gets beyond the gut and it gets into the circulation of the body. That's why one snake could, for instance, eat another snake, and it wouldn't be poisoned by it. In the same way, a person who has diabetes may need to inject the hormone insulin. Insulin is a protein, so if you were to take it by mouth the digestive tract would break it down. That's why people have to inject insulin to make it work. So why don't snakes poison themselves, given they have the venom in their bodies? It's exactly the same reason that you remain healthy despite the fact that your pancreas makes a deadly cocktail of digestive juices which, if they got into your bloodstream, would kill you very rapidly. People who get the condition acute pancreatitis have a very high mortality rate. It kills people because they literally eat themselves from the inside out. The reason that they don't do that normally when you're healthy is because the enzymes are made in cells in an inactive state. They're exported from the cell into a duct which is lined with special protecting cells that stop it going back in to the body's own tissues and doing any damage. The only place it can go is down the duct and then out into the digestive tract. If you put that into the context of the snake, it's got a gland which knows how to make the proteins in the venom. They get exported into this duct which is a special holding bay, protected from the venom. It can't go back the wrong way or into the snake's bloodstream. When the snake bites you there are tiny muscle cells around those ducts and it squirts the venom down its fangs (there are ducts in there) and into the holes that the teeth have made in you. That's why the snake doesn't die from its own venom because it keeps it in a specially adapted part of the body so it can't get into the circulation. I did ask a snake venom researcher this question once and he said you can also find antibodies in snakes to their own venom, to a certain extent. They kind of have their own antivenom built it. Possibly because they have exposed themselves at low level, or been exposed during altercations with other snakes. I don't know how protective that is so there's two mechanisms there why a snake doesn't poison itself.


i live in the Hudson valley, NY state, i see a good number of these snakes while hiking. They dont bother me and i don't bother them. I do feel that another reason for a timber rattler to have immunity is that its always dining on mice and chipmunks which it has killed; wouldn't that expose the snake to a lot of venom ? Sure , the stomach will digest some of it, but it seems also true that the capillaries of the mouth would be exposed to venom. Could explain another way that the snake gets immune....... ??? makes sense to me. would have to discuss with a herpetologist and i don't have one handy. i also really need to know the chemical mechanism by which the snake manufactures venom and why this is considered a taxing process for the snake, so much so that it's reluctant to bite unless its sure its going to get food --- snake does not want to waste venom since it's not readily produced. yes, i tried googling ---- no specific answers found.

You make some interesting points. I am not sure about the exposure to venom across mucous membranes; my instinct, however, is that this is not an issue. Snakes swallow their prey whole, and the nature of envenomation means that the venom will be deeply injected into the prey animal's body, so I suspect the exposure via this route is going to be low - the vast majority of the venom will see the gastric juices and be degraded. In terms of the cost of venom production, these are proteins, meaning they are nitrogenous molecules, and nitrogen is precious in the body. You need to be eating food to make them. Ergo, if you are too profligate in their use, you'll be in negative nitrogen balance. The venoms also take time to make, and to guarantee a kill a snake needs to administer an adequate dose, so it needs to ensure that it has accumulated sufficient venom to immobilise its prey. Again, if it is too wasteful and depletes its reserves, then there is a chance that lunch might escape...

this is so awsome!!!!!! cool!!!!!!!!!!!!!!

I was bitten by a small timber rattler on the inside of my ankle, My whole leg swelled up and turned black blue and green. The doctors thought they were going to have to slice my leg the swelling was so bad. I was only givin antibiotics, no anti venom. REALLY PAINFUL. when I first got bit I wanted to die, the shot of morphine got me through it. Only took one more shot of morphine and 2 darvasets. I tell people I meaner than a rattle snake.

LOL that is cute! "i tell people i meaner than a rattle snake." aw, i bet you're a sweety (still LOLing)

Add a comment