Spider Tales 3: The Widow and the Rattlesnake... And other LD50 stories
"A black widow's venom is 15 times more toxic than a rattlesnake's" National Geographic documentary It's definitely one of the most commonly shared pieces of spider trivia. It's hard to escape it: every time a wildlife documentary features a black widow, you can bet this comparison with rattlesnake venom will pop up at some point. You may be surprised, then, to learn that this claim doesn't say much about how "deadly" those spiders are. Actually, it doesn't say much about anything: although it does sound a lot like a fact, it's just a meaningless factoid , little more than a mere urban legend. Venom 15 times as potent as a rattlesnake's? That sure sounds scary... But what does it mean? Similar comparisons, based on LD50 values, are also often shared about some species of venomous snakes (particularly some Australian Elapidae famous for b