Krais wrote:
Blackwidow is deadly, not for its poison.. but because when you take the anti-venom to get rid of it, tons of people are allergic to it and die from it..
It's venom is much more potent as the one from snakes, but they don't inject as much > not that deadly.
wiki wrote:
Although their venom is extremely potent, (15 times as potent than that of the rattlesnakes; it is also reported to be much more potent than the venom of cobras and coral snakes), these spiders are not especially large. Compared to many other species of spiders, their chelicerae are not very large or powerful. In the case of a mature female, the hollow, needle shaped part of each chelicera, the part that penetrates the skin, is approximately 1.0 mm (around .04 inch) long, sufficiently long to inject the venom to a dangerous depth. The males, being much smaller, can inject far less venom and inject it far less deeply. The actual amount injected, even by a mature female, is very small in physical volume. When this small amount of venom is diffused throughout the body of a healthy, mature human, it usually does not amount to a fatal dose (though it can produce the very unpleasant symptoms of Latrodectism). Deaths in healthy adults from Latrodectus bites are relatively rare in terms of the number of bites per thousand people. Only 63 deaths were reported in the United States between 1950 and 1989. On the other hand, the geographical range of the widow spiders is very great. As a result, far more people are exposed, world-wide, to widow bites than are exposed to bites of more dangerous spiders, so the highest number of deaths world-wide are caused by members of their genus. Widow spiders have more potent venom than most spiders, and prior to the development of antivenom, 5% of reported bites resulted in fatalities.