Poison vs Venom - clarification regarding spiders

[The Snark]

Poisonous: A substance containing a poison.
Venomous: A living organism that produces a venom.
To say a spider is poisonous is inaccurate. An animal could eat a spider and probably suffer no ill effects.*

A venom is a secretion in certain animals that contains one or more toxins.
A toxin is a substance that causes an adverse or abnormal condition in a living organism.
A poison is typically but not limited to a chemical that causes a disease a living organism.
A disease is any condition that impairs normal function in a living organism.

Nearly all spiders have glands that secrete venom. The venom consists of one or more toxins which is/are poisonous and causes disease.

The ladder, chain of events in a spider bite, is from specific to general: Venom->Toxin->Poison->Disease


* Eating a venom. Venoms typically consist of proteins. The digestive system is designed to break down proteins, usually rendering the toxic effects in them harmless.

 

[Pyroxian]

Maybe a tad oversimplified, but I've always liked the couplet "if you bite it and get sick it's poisonous. If it bites YOU and you get sick it's venomous"

 

[Pepper]

Very informative! I didnt know the part about the digestive system and proteins, or the ladder. Thanks!

 

[Arthroverts]

We need to get this stickied so that newbies know how to properly describe their specimens.

Thanks,

Arthroverts

 

[akazaran]

Just to clarifiy a toxic substance that has to be injected to cause harm is also considered as a poison. The definition of poison is not restricted to substance that have to be ingested to cause harm. Hence technically a venom is always a poison but the opposite is not always true.

 

[EtienneN]

Have any humans ever actually eaten a venom gland from a venomous creature? Maybe they do. Do the tribes that eat Haplopelma/Cyriopagopus albostriatum also eat its venom glands??? I feel like ingesting multiple venom glands from multiple tarantulas would at least give you a sour stomach but maybe not!

 

[The Snark]

Just to clarifiy a toxic substance that has to be injected to cause harm is also considered as a poison. The definition of poison is not restricted to substance that have to be ingested to cause harm. Hence technically a venom is always a poison but the opposite is not always true.

Well put. We have a nomenclature and terminology problem here that can make this extremely complex.

In the case of a spider bite, A venom is a glandular secretion, emphasis on A. There are numerous other types of venoms that are not glandular secretions.
-Glandular secretion venoms are evolved complex proteins that have developed to target specific animals or organisms. An excellent example can be found on @Widowman10 web site: https://sites.google.com/site/widowman10/venom.

Then examine a more primitive 'venom' that technically is and isn't a glandular secretion found in the cone shell. This 'venom' is comprised of amino acids which are the building blocks of proteins. The toxins of the cone shell could best be described as a shotgun blast of a large assortment of these amino acids that have not evolved into specific proteins that target specific organisms. The effect of these non specific toxins on humans depends upon the cone shell species, the environment that animal lives in and several random factors, and can be anything from harmless to a mild irritant and on up to lethal.
So suffice to say a venom is a venom unless it isn't a venom but a seemingly random collection of amino acids, some of which are toxins and are medically significant. The general rule is venoms are proteins, the building blocks of proteins, or a derivative of what is or was a protein or it's component parts.

Then we move up the ladder to the more general term toxin. A toxin is a substance that causes an adverse or abnormal condition in a living organism. More specifically, a substance that causes a deleterious bio-chemical alteration. This instantly becomes much more complex when we attempt to define the adverse or abnormal condition. 78% of the air we breath is nitrogen. Increase the concentration a few percentage points and it causes an adverse or abnormal condition.

And this takes us up to the more general term in the ladder, poisons. Technically, everything is a poison. Sun light, oxygen, water, you name it. It depends entirely on circumstance and leads to the fourth rung of the ladder, susceptibility to disease.

And on a side note:

Have any humans ever actually eaten a venom gland from a venomous creature? Maybe they do. Do the tribes that eat Haplopelma/Cyriopagopus albostriatum also eat its venom glands??? I feel like ingesting multiple venom glands from multiple tarantulas would at least give you a sour stomach but maybe not!

This appears to be an evolved safety net in animals that produce venom. As mentioned, venoms are proteins comprised of amino acids. The digestive systems vary from animal to animal but as a general rule they alter or outright destroy proteins and or their component parts. Thus an animal can eat it's own venom, quite common, and suffer no ill effects - disease. Digestive systems are quite general, depending upon if the animal is an herbivore, omnivore or carnivore. Since the food sources can vary so drastically, the digestive system is normally capable of working on a very wide spectrum of materials.

(Please note, all the above is simplified. I'm deliberately skirting peptides, covalent bonds and all of rabbits friends and relations.)