Wolf spiders are a family of mostly large, hairy and athletic arachnids. Rather than catching their prey in webs, wolf spiders chase it down similar to the way a wolf does, although these spiders hunt alone, not in packs.

There are nearly 2,400 wolf spider species across 125 genera, according to the Integrated Taxonomic Information System (ITIS). They live around the world and are found throughout the U.S. Wolf spiders are especially common in grasslands and meadows, but they also live in mountains, deserts, rainforests and wetlands — anywhere they can find insects to eat, according to the University of Michigan's BioKids website.

What do wolf spiders look like?

Wolf spiders are usually brown, gray, black or tan, with dark markings — most commonly stripes, according to the Missouri Department of Conservation. Their coloring is effective camouflage, helping them catch their prey and hide from predators. Wolf spiders' size varies, and their body lengths range from about a quarter of an inch (0.6 centimeter) to over an inch (3 cm) long, not including their legs. The Desertas wolf spider (Hogna ingens) from Deserta Grande Island in the Atlantic Ocean is one of the largest wolf spiders and has a leg span of 4.7 inches (12 cm), according to the Bristol Zoological Society in England. Female wolf spiders are typically larger than males.

Wolf spider taxonomy

Kingdom: Animalia

Phylum: Arthropoda

Class: Arachnida

Order: Araneae

Family: Lycosidae

Source: ITIS

Wolf spiders have a "distinctive eye arrangement, where the front or anterior row is composed of four small eyes of roughly the same size arranged in almost a straight row," said Jo-Anne Nina Sewlal, an arachnologist at the University of the West Indies in Trinidad. (Sewlal spoke with Live Science in 2014 and died in 2020.) "The back or posterior row is arranged in a V-pattern with the apex next to the anterior row." Wolf spiders have excellent night vision and primarily hunt in the dark. "They are also quite easily detected at night due to their eyeshine," Sewlal said.

Related: Furry 'Harry Potter' spider discovered in mountain burrow

Are wolf spiders dangerous?

Wolf spiders can bite if threatened, but their venom doesn't pose a serious danger to humans. According to Penn State's College of Agricultural Sciences, wolf spiders bite humans when they are mishandled or trapped next to the skin. Bite victims may exhibit some redness or swelling, but no serious medical problems caused by a wolf spider bite have ever been reported. However, wolf spider bites can be very painful, so these critters shouldn't be picked up by hand, the University of Kentucky's Department of Entomology notes.

Brown wolf spiders can be confused with more venomous brown recluse spiders, especially in houses. Fast-moving spiders on the ground are more likely to be wolf spiders, as brown recluse spiders are very rarely seen out in the open, according to the University of Kentucky. People can tell the spiders apart using size and banding patterns; wolf spiders are usually larger and have banding patterns on their legs, which are absent on brown recluse spiders. Anyone who has been bitten by a brown recluse spider should seek emergency medical attention, according to MedlinePlus, a service of the National Library of Medicine.

Habitat and feeding

Wolf spiders are solitary animals that typically roam alone in the night, stalking prey. They are "mostly nocturnal and often mistaken for tarantulas," Sewlal said. These spiders spend most of their time on the ground, but they can climb trees or other objects if they need to. Their habitats include stream edges, gravel and low vegetation, according to the Missouri Department of Conservation. Wolf spiders sometimes find their way into houses, usually in basements, crawl spaces and breezeways after they enter near ground level, according to Michigan State University's Plant & Pest Diagnostics.

Wolf spiders eat mostly ground-dwelling insects, such as crickets and other spiders. Large females may take on small amphibians and reptiles, according to BioKids. Some species chase down and seize their prey, while others wait for prey to walk by and then ambush it. Wolf spiders often jump on their prey, hold it between their legs and roll over on their backs, trapping their prey with their limbs before biting it and injecting their venom.

Wolf spiders use their keen eyesight, camouflage, speedy movements and high sensitivity to vibrations to help them avoid predators such as lizards, birds and hunting wasps. According to the Smithsonian, hunting wasps paralyze wolf spiders with a sting, drag them back to burrows and lay eggs in them so larvae hatching from the eggs have something to eat.

Related: Rare wolf spider presumed extinct turns up on British military base

Mating

Female wolf spiders leave scent markings so males can find them to mate. When a male locates a female, they perform a courtship ritual in which the male signals to the female by waving its legs and pedipalps (short, sensory appendages near their mouths), according to the Australian Museum in Sydney. After mating, female wolf spiders lay several dozen or more eggs and wrap them in silk, creating an egg sac.

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"Female wolf spiders carry their egg sacs attached to her spinnerets [at the tip of their abdomens where silk is produced]," Sewlal said. Mothers are known to exhibit aggressive behavior when carrying their egg sacs. They sometimes need to drop their egg sacs to more easily escape predators. If this happens, females will search furiously to find them again and may even pick up another wolf spider's abandoned egg sac to care for. A 2021 study published in the journal Ethology found that Pardosa milvina, a common North American wolf spider, can recognize its own egg sacs and is less likely to pick up those of unrelated spiders when given a choice. However, the spiders in the study cared for unrelated eggs as if they were their own when they did pick them up.

Wolf spiders' maternal behavior doesn't stop with the egg sacs. "After hatching, the spiderlings climb on their mother's back, and she carries them around for several days," Sewlal said. After this, the spiderlings leave their mothers and go off alone. Male wolf spiders typically live for one year or less, while females can live for several years.

Related: Kinky wolf spiders engage in ménage à trois to avoid cannibalism

Additional resources

To see a size and visual comparison of wolf spiders and brown recluse spiders, check out this graphic from the University of Nebraska–Lincoln, which highlights the differences between the two types of spider, as well as other species that can be confused with brown recluse spiders. To learn more about Desertas wolf spiders, a critically endangered species, and what Bristol Zoological Society and other groups are doing to save them, check out the organization's Desertas Wolf Spider Conservation Strategy. To see how wolf spiders move, watch this short YouTube video by the Billings Gazette, a Montana-based newspaper.

Bibliography

Berry, A. D. & Rypstra, A. L. "Egg sac recognition and fostering in the wolf spider Pardosa milvina (araneae: lycosidae) and its effects on spiderling survival," Ethology, Volume 127, Jan 29, 2021. https://onlinelibrary.wiley.com/doi/abs/10.1111/eth.13134

BioKids, Animal Diversity Web, University of Michigan, "Lycosidae," 2001. http://www.biokids.umich.edu/critters/Lycosidae/

Bristol Zoological Society, "Desertas Wolf Spider." https://bristolzoo.org.uk/save-wildlife/conservation-and-research/desertas-wolf-spider-project

Blake Newton, University of Kentucky Department of Entomology, "Wolf Spiders," updated Jan. 30, 2008. https://www.uky.edu/Ag/CritterFiles/casefile/spiders/wolf/wolf.htm

College of Agricultural Sciences, The Pennsylvania State University, "Wolf Spiders," updated Dec. 10, 2018. https://extension.psu.edu/wolf-spiders

Integrated Taxonomic Information System (ITIS), "Lycosidae Sundevall, 1833," reviewed 2019. https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=847731#null

Medline Plus, National Library of Medicine, "Brown recluse spider," updated Feb. 18, 2022. https://medlineplus.gov/ency/article/002859.htm

Missouri Department of Conservation, "Wolf Spiders." https://mdc.mo.gov/discover-nature/field-guide/wolf-spiders

Plant & Pest Diagnostics, Michigan State University, "Wolf Spider," May 19, 2020. https://www.canr.msu.edu/resources/wolf-spider

Smithsonian, "Wolf Spider," Dec. 5, 2014. https://www.si.edu/newsdesk/snapshot/wolf-spider

The Australian Museum, "Wolf Spiders," updated Aug. 23, 2021. https://australian.museum/learn/animals/spiders/wolf-spiders/

This article was originally published on Dec. 25, 2014. It was updated on March 7, 2022, by Live Science staff writer Patrick Pester.