The Everyday Animal: Black Widows

For the weekend before Valentine’s Day it seemed morbidly appropriate to do a post about the classic model of a bad relationship. Though they may strike fear into many of our hearts, they really are amazing creatures and have been given a largely unfair reputation as dangerous pests.

The main reason for this reputation is that black widows are one of only two venomous spiders in North America, the other being the brown recluse. While black widows have a tremendous amount of neurotoxin venom that they can inject, they very rarely if ever inject more than a small amount. This small amount is still dangerous, and immediate medical attention should be sought after being bitten, however, death very rarely occurs.

It has long been believed that black widow females, which are recognizably large black shiny, ate their mates immediately after mating. As it turns out, this is a widely believed myth. While this occurs occasionally true, it is far from a sure thing, and the majority of the time the males get away unharmed. But before all you male spiders out there breathe a sigh of relief, be aware that the life of a male black widow is still far from easy. Males are brown, small, rather plain looking and lack the dangerous venom of the females. As adults males never eat, but instead spend their entire nomadic life looking for females to mate with. So if you are alone this holiday, at least you can take solace in knowing you are not a male black widow.

Although the myth of cannibalism after mating is largely false, black widows are far from unfamiliar with cannibalism. Every summer, black widows can produce 4-9 egg sacs each containing 100-900 eggs (many sources had vastly different numbers, even for the same species). Of all of these babies, only about 1-12 survive, and why? Not because of predators, lack of food, but cannibalism! Yes, once hatched, within about 20 days all of the hundred(s) of eggs begin eating each other. This is done so that the few left will be much stronger, bigger, and well fed than they might be otherwise, better ensuring their survival. Still… so macabre (thank you word-a-day calendar).