# Black Widow Spider (*Latrodectus mactans*)

> The southern black widow (Latrodectus mactans) is a small, glossy black spider famous for the red hourglass marking on the underside of the female's abdomen. It shelters in dark, undisturbed spots such as sheds, woodpiles and field debris, where it builds a tangled web to trap insects. The female's body is only about 1.3 cm long, yet her venom is a potent neurotoxin. Females live one to three years; males are far smaller and shorter-lived.

- **Category:** Invertebrate
- **Conservation status (IUCN):** Least Concern
- **Range:** Sheltered, dark places across North America, especially the southern and western United States.
- **Canonical page:** https://globalanimalguide.org/animals/black-widow-spider/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Arthropoda
- **Class:** Arachnida
- **Order:** Araneae
- **Family:** Theridiidae
- **Genus:** Latrodectus

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Latrodectus mactans |
| Diet | Carnivore (insects and other small arthropods) |
| Habitat | Sheltered, dark spots in fields, sheds, and woodpiles |
| Lifespan | 1–3 years (females; males much shorter) |
| Size | Female body about 1.3 cm (0.5 in); legs wider |
| Venom | Potent neurotoxin; bites rarely fatal with care |
| Conservation status | Least Concern (IUCN) |

## Appearance and identification

The female black widow is unmistakable: a shiny jet-black body roughly 1.3 cm (0.5 inch) long, with legs spanning wider, and a vivid red hourglass on the underside of her rounded abdomen. Males are much smaller and paler, often marked with red or yellow streaks, and are rarely noticed. The glossy sheen and bold warning colour advertise the spider's toxicity to would-be predators. Juveniles look different again, with lighter, more patterned bodies that darken as they mature.

## Web and how it catches prey

Black widows are ambush hunters that rely entirely on their web rather than chasing anything down. They spin an irregular, tangled cobweb of exceptionally strong silk in a sheltered corner, then wait, hanging upside down at its centre. When an insect blunders into the sticky threads, the spider rushes over, wraps it in silk and delivers a paralysing bite. It then injects digestive enzymes and drinks the liquefied remains. Prey is mostly insects and other small arthropods.

## Venom and danger to people

Black widow venom is a neurotoxin called latrotoxin, drop for drop far more potent than a rattlesnake's, which is why the spider has such a fearsome reputation. A bite can cause intense muscle pain, cramping, sweating and nausea, a set of symptoms known as latrodectism. In practice, however, the spider injects only a tiny dose, and with modern medical care bites are very rarely fatal. Deaths are extremely uncommon, and most affect the very young, the elderly or those already unwell.

## Behaviour and temperament

Despite their reputation, black widows are shy and reclusive, biting people only when accidentally pressed against the skin or trapped. They are largely nocturnal and slow-moving, ambling across their web at little more than 1.5 km/h. Females spend almost their entire lives within a small web, rarely straying far from this sheltered refuge. Left alone, a black widow poses very little threat and would much rather retreat than confront a much larger animal.

## Mating and life cycle

The black widow earns its name from the female's occasional habit of eating the much smaller male after mating, though this happens far less often than folklore suggests. After mating, the female produces several round, papery egg sacs, each holding hundreds of eggs, which she guards within her web. The spiderlings hatch and disperse by releasing silk threads that carry them on the breeze, a technique called ballooning. Females can live one to three years, while males survive only a few months.

## Frequently asked questions

### How dangerous is a black widow bite?

A black widow's venom is a potent neurotoxin that can cause severe muscle pain, cramps, sweating and nausea. Despite this, the spider injects only a small dose, and with prompt medical care bites are very rarely fatal.

### How do you identify a black widow spider?

Look for a glossy jet-black female about 1.3 cm long with a bright red hourglass marking on the underside of her rounded abdomen. Males are much smaller, paler and usually go unnoticed.

### Do female black widows really eat the male?

Sometimes, but far less often than the name implies. Cannibalism after mating does occur in this species, yet in many encounters the male escapes unharmed, and the behaviour is more common in captivity than in the wild.

### What do black widow spiders eat?

They are carnivores that feed mainly on insects and other small arthropods caught in their web. The spider waits at the centre of its tangled web, then wraps and bites any prey that becomes stuck.

### How long do black widow spiders live?

Females typically live one to three years. Males are much smaller and live only a few months, often dying not long after they mate.

### Where do black widow spiders live?

They favour dark, sheltered and undisturbed places such as sheds, woodpiles, rock crevices and debris in fields. There they build a tangled cobweb close to the ground and remain hidden during the day.

## Sources

- [IUCN Red List — Latrodectus mactans.](https://www.iucnredlist.org/search?query=Latrodectus%20mactans&searchType=species)
- [Animal Diversity Web — Latrodectus mactans. University of Michigan Museum of Zoology.](https://animaldiversity.org/accounts/Latrodectus_mactans/)
- [Wikipedia — Black Widow Spider.](https://en.wikipedia.org/wiki/Latrodectus_mactans)

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Source: Global Animal Guide (https://globalanimalguide.org/animals/black-widow-spider/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.