...rattlesnakes, cobra snakes, pit vipers, mambas, etc. are venomous, not poisonous. Plants, chemicals, and gases may be poisonous, but you can swallow snake venom without adverse consequences. Only after injection (envenomation) does it become toxic and potentially lethal.
That's a subtle grammatical difference I hadn't paid attention to in the past; I just went back through TYWKIWDBI to correct several such errors.
Of additional interest, as I looked up the etymologies I discovered that "venom" traces back through ME "venim" to OF and eventually to the Latin "venemum," referring not just to a poison (!) but to a "love-potion" because it is related to "ven(us)".
(Green mamba credit here)
