If two rattlesnakes of the same species fight, neither will be harmed by the venom they inject. The venom of the tiny Blue-ringed Octopus contains tetrodotoxin, one of the most potent neurotoxins known. Human death from heart and respiratory failure can occur within minutes. An adult rattlesnake can rattle at a rate of 50 times per second. A snake would rather frighten away a predator with a harmless strike than deplete its store of venom.
Snake venom is used in painkillers, blood thinners, and blood clotting agents.
Cone snail venom is 1000 times as powerful as morphine. There are more than 34,000 species of spiders, and all are technically venomous. However, only 20-30 pose a danger to humans. Tarantulas are named for the city of Taranto, Italy, where legend has it that a dance was once performed there to cure the effects of the spider's bite. In the United States each year, bees and wasps account for approximately 500 human deaths.