10 Interesting Facts About Black Widow Spiders


Black widow spiders are known around the world for eating their males after mating. They are also feared as they are the most venomous spiders in North America. Know more about this amazing animal through these 10 interesting facts.


#1 Sexual Cannibalism in black widows may be due to male sacrifice

The Black WidowThe female black widow spiders usually eat their male partners after mating. This sexual cannibalism has inspired the common name for this species. Researchers at the University of Hamburg in Germany found that male black widow spiders make this ultimate sacrifice to provide nutrition to the eggs.

#2 Their venom causes a condition known as Latrodectism

The black widow spiders belong to the genus Latrodectus. The genus contains 32 recognized species. They are present in every continent except Antarctica. The venom injected by the bite of these spiders contains the neurotoxin latrotoxin which causes the condition latrodectism, both named after the genus.

#3 Australian Redback Spider also belongs to the same genus

The species in the genus Latrodectus include northern black widow (Latrodectus variolus), southern black widow (L. mactans) and western black widow (L. hesperus) found in North America; European black widow (L. tredecimguttatus) found throughout the Mediterranean region; Australian redback spider (L. hasseltii); and the button spiders of Africa.


#4 Female Black Widows have a red hourglass mark on their abdomen

Female black widows are usually identified by a red hourglass shape on their abdomen and shiny black bodies. In fact any spider having a red hourglass shaped mark on its abdomen is an adult female black widow. Although all black widows don’t have this mark. The shiny body is a warning to potential predators of their toxicity.

Hourglass marking on an adult female black widow
The distinctive red hourglass marking on an adult female black widow


#5 The females are three times more venomous than the males

The venom of a female black widow is three times more potent that the male. Therefore the bite of a male black widow is not that dangerous to humans. It is the bite of the adult female black widow from her much larger venom sacs that can cause some problems. The size of the female black widows, which is about 1.5 inches, is also nearly double of that of males.

Female and male black widow spiders
Female (top) and male black widow spiders


#6 In most cases bite of a black widow spider causes no serious problems

A bite of Latrodectus may not inject any venom (dry bite) and hence cause no illness. About 75 percent of bites which are venomous (wet bite) will only cause localized pain and nothing more. If, however, a substantial amount of venom is injected by the bite it leads to latrodectism, which is marked by pain, muscle rigidity, vomiting, and sweating. It usually lasts for 3 to 5 days.

Latrodectus Hasseltii
A redback spider (Latrodectus hasseltii)


#7 However their bite can be fatal to children and the elderly

Latrodectus Hesperus
Western Black Widow (Latrodectus hesperus)

The venom of the black widow spider is reported to be 15 times stronger than a rattlesnake’s. Due to this it is much feared but contrary to popular belief, most people who are bitten by the black widow spider suffer no serious damage. However the bite can be fatal to small children, the elderly or the infirm.

#8 Black widows attack only in self-defense

Black widow spiders are not known to be aggressive and attack only in self-defense, such as when they are squeezed or pinched. While some species might be more aggressive than others, most injuries to humans are due to defensive bites.

#9 Black widows are comb-footed spiders

Black widow spiders belong to the family Theridiidae, also known as comb-footed spiders, so called “because they have a series of stiff short hairs on the last segment of their fourth pair of legs that resemble the teeth of a comb.” They use them to cover their prey with silk once it is trapped. Their prey includes flies, mosquitoes, grasshoppers, beetles, and caterpillars.

Southern Black Widow Spider
Southern black widow eating its prey


#10 They liquefy their prey before consuming it

Black widow spiders construct a web of irregular, tangled, sticky silken fibers. They usually hang upside down near the center of their web. If an insect gets stuck, black widows rush to bite it and wrap it in silk. They then puncture their prey with fangs, inject enzymes to liquefy the corpse and suck up the resulting fluid to appease their hunger.

3 thoughts on “10 Interesting Facts About Black Widow Spiders”

  1. It’s a relief that you mentioned that black widows will only attack out of self-defense. I’ve been having a bit of a spider problem in my garden and I’m not sure how to get rid of them without any harm. Maybe it would be best if I just let a spider control service handle it.

  2. The reflection in the sun upon these things wll scwre away birds and several other creatures.
    The unwelcome guests chew on a wide variety of things
    including electrical wires. Micee and cockroaches, forr
    example, reproduce quickly aand many times, therefore it is important to remove these
    animals you’d like possible.


Leave a Comment