Black widow spiders typically eat once every one to two weeks, though their feeding schedule is highly irregular and depends on what stumbles into their web. Unlike animals that actively hunt on a schedule, black widows are sit-and-wait predators. They can go remarkably long stretches without food, sometimes months, making them one of the more resilient spiders when meals are scarce.
Feeding Frequency in the Wild
Black widows don’t eat on a predictable timetable. A spider with a well-placed web in a bug-rich area might catch and consume prey several times a week. One in a less productive spot might go weeks between meals. The average works out to roughly one feeding every week or two during warmer months, but “average” doesn’t capture how uneven their eating really is. They’re opportunistic: they eat when something gets tangled in the web, and they wait when nothing does.
Temperature plays a major role. In warm weather, a black widow’s metabolism runs faster, so it needs more energy and feeds more often. As temperatures drop, its metabolism slows, and it can stretch much longer between meals. This is why black widows in cooler climates or during autumn may seem almost dormant compared to their summer activity.
How Long They Can Go Without Food
Black widows are built for famine. Research on closely related widow spiders found that immature spiders survived up to 160 days without food, while some adults lasted more than 300 days. Two adult females in one study were still alive after 307 days at cool temperatures. That’s over 10 months without a single meal.
This extreme starvation tolerance is partly a product of their low metabolic rate and partly because their digestive system is designed for irregular feeding. Their bodies store digestive enzymes in a kind of inactive state between meals, with built-in molecular “locks” that keep the enzymes preserved until the spider actually needs them. When prey finally arrives, the enzymes activate and get to work.
What Black Widows Eat
The bulk of a black widow’s diet is insects. Flies, mosquitoes, beetles, grasshoppers, caterpillars, and ants are all common prey. Anything small enough to get caught in the web’s sticky silk is fair game. Their venom actually contains different toxic components tailored to different types of prey: one set targets insects, another targets crustaceans like pillbugs, and a third affects vertebrates.
That vertebrate-targeting venom isn’t just for self-defense. Small vertebrates, including lizards, tiny snakes, and even mice, are infrequent but real parts of the black widow diet. These larger catches are rare, but when they happen, they provide a massive caloric payoff that can sustain the spider for weeks.
How They Digest a Meal
Black widows can’t chew. Like roughly 80% of spider species, they use a process called extra-oral digestion, which means the actual breakdown of food happens outside their body. After biting prey and injecting venom to immobilize it, the spider floods the prey’s body with digestive fluids containing powerful enzymes that dissolve tissues into liquid. The spider then drinks this nutrient-rich soup through its tiny mouth.
This process isn’t fast. A single meal can take anywhere from several hours to an entire day to fully consume, depending on the size of the prey. The spider wraps the catch in silk, returns to it repeatedly, injects more digestive fluid, and sips. What’s left behind is a dry, hollow husk. Because digestion takes so long, black widows don’t need to eat frequently to meet their energy needs. One well-sized cricket can fuel an adult female for a week or more.
Sexual Cannibalism and Feeding
The black widow’s name comes from the widespread belief that females always eat the male after mating. The reality is more nuanced but still striking. Research on South American widow spiders found that 70% of males were killed by females during their first mating, and that number jumped to 85% when the female had already mated before. Studies on Australian redback spiders (another widow species) put the rate around 65%.
For species where cannibalism rates are high, the male’s body provides a genuine nutritional boost. A well-fed female produces more eggs, so from an evolutionary standpoint, the male’s sacrifice isn’t entirely wasteful. In North American black widows specifically, cannibalism during mating appears less common than in their Australian and South American relatives, though it still happens.
Captive Feeding Schedules
People who keep black widows in captivity, whether for research or as pets, typically offer food once or twice a week. A single cricket or a few small insects per feeding is standard for an adult female. Juveniles eat smaller prey like fruit flies or pinhead crickets and benefit from slightly more frequent feedings since they’re actively growing and molting.
Overfeeding isn’t a common concern because black widows will simply ignore prey when they’re not hungry. If a cricket sits untouched in the enclosure for more than a day, it’s a sign the spider doesn’t need food yet. Many keepers find their spiders go through visible cycles of heavy eating followed by stretches of disinterest, particularly around molting, egg production, or temperature changes.