Facts About Black Widows

Black widows are very well-known for being one of the most poisonous spiders in the world. They are the most popular of the 31 known species of widow spiders of the genus Latrodectus. These spiders are called widows because the female often eats the male after mating. However, there are some instances when the male goes away scot-free after mating and is able to mate with other females.

Black widows appearance

A black widow spider has a shiny black color covering their entire bodies, except for a red spot on the underside of the abdomen. This red spot often comes in the form of an hourglass but it can also be just two red dots. Some black widows have no spots at all and are entirely black. Male black widows can also be a dark brown or gray color instead of the usual black.

Males are smaller than females

They are relatively small compared to other poisonous spiders and weigh an average of only one gram. The females are much larger than the males, sometimes measuring twice or thrice the size of an average male. Aside from this vast difference in size, you can also distinguish between the males and the females by the fact that females usually hang upside down from the middle of their webs, waiting for prey.


Although black widows in general are quite feared for their venomous bite, it is actually just the females that pose a serious threat to humans because they have much larger venom sacs than the males. Bites from male black widows are not that dangerous although they can also be quite painful and still require immediate medical treatment.

Female black widows

A bite from a female black widow, on the other hand, can be fatal at times, especially to young children and those who have very weak immune systems. Some of the initial symptoms of a bite by a female black widow spider include nausea, soreness of the muscles and breathing difficulties. An antivenin should be used as soon as possible after being bitten.

More dangerous than rattlesnakes

It is also interesting to note that the venom of a black widow is 15 times more lethal than that of a rattlesnake, which is why people fear this spider so much. However, black widows are not really known for aggressively attacking humans. In fact, they prefer a solitary existence away from humans. When they bite, it is usually as a defensive move when they feel threatened.

Mating and Reproduction

The mating ritual of black widows is not that complicated. It begins with the male slowly approaching the female as she hangs from her web. The male make some kind of tapping motion with his feet, signaling his intention. When the female is ready, she will stay still and allow the male to mount her and release his sperm.

Life cycle of black widows

A female black widow can lay up to 400 eggs at a time, which she will watch until they hatch after 20 days. It will take up to two months before these baby spiders will reach their full-grown size. The average lifespan of a black widow is three years.

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