G
Species Profile

Grass Spider

Agelenopsis

Dew-lit sheets, lightning-fast hunts.
Elliotte Rusty Harold/Shutterstock.com

Grass Spider Distribution

Click a location to explore more animals from that region

Loading map...
Grass Spider, Agelenopsis sp.

At a Glance

Genus Overview This page covers the Grass Spider genus as a group. Stats below are general traits shared across the genus.
Also Known As Funnel weaver, Funnel-web spider, Grass funnel weaver
Activity Crepuscular+
Lifespan 14 years
Weight 0.0003 lbs
Status Not Evaluated
Did You Know?

Size across the genus: roughly ~5-20 mm body length (legspan often ~2-5+ cm), with females typically larger than males.

Scientific Classification

Genus Overview "Grass Spider" is not a single species but represents an entire genus containing multiple species.

Grass spiders (Agelenopsis) are funnel-weaver spiders that typically build horizontal sheet webs in grasses, shrubs, and around buildings, with a funnel-like retreat where the spider waits for vibrations from prey.

Kingdom
Animalia
Phylum
Arthropoda
Class
Arachnida
Order
Araneae
Family
Agelenidae
Genus
Agelenopsis

Distinguishing Features

  • Sheet web with a distinct funnel retreat (a tube-like hiding place)
  • Long, visible spinnerets often extending beyond the abdomen tip (a common Agelenidae trait)
  • Fast-running spiders that usually retreat into the funnel when disturbed
  • Often patterned with longitudinal striping/banding on the cephalothorax and abdomen (varies by species)

Physical Measurements

Males and females differ in size

Length
0 in (0 in – 1 in)
Weight
0 lbs (0 lbs – 0 lbs)
0 lbs (0 lbs – 0 lbs)
Top Speed
4 mph
No verified speed data
Venomous

Appearance

Primary Colors
Secondary Colors
Skin Type Hard chitinous exoskeleton with fine hair-like setae (often giving a matte or slightly velvety look); long, conspicuous posterior spinnerets typical of funnel weavers.
Distinctive Features
  • Adult body length across the genus is variable, commonly ~0.6-2.0 cm (with males typically on the smaller end and females often reaching the larger end; legspan proportionally larger).
  • Elongated posterior spinnerets (a key Agelenidae trait) are usually visible from above and are an important identification cue.
  • Funnel-weaver sheet-and-funnel web architecture: a horizontal sheet web leading into a tubular funnel retreat where the spider waits for prey vibrations; webs are frequently conspicuous when highlighted by morning dew.
  • Commonly associated with lawns, grasses, low shrubs, and also human structures (foundation plantings, corners of buildings, window wells); exact microhabitat and web placement vary among species and local conditions.
  • Behavior/ecology generalization: sit-and-wait in the funnel, then rapidly dash out onto the sheet to seize prey; activity can be day or night depending on conditions, with some seasonal/individual variation.
  • Seasonal variation is common: mature males often leave webs and wander while searching for females, increasing their likelihood of being found indoors; females more often remain web-associated.
  • Often confused with wolf spiders (Lycosidae), but Agelenopsis typically has a funnel web and conspicuously long spinnerets; wolf spiders generally do not build sheet-and-funnel webs.
  • Lifespan across the genus is usually about ~1 year, but can extend to ~2 years in some climates/populations (often overwintering as juveniles and maturing the following season).
  • Bites are uncommon; when they occur, effects are typically mild and localized (medical significance should not be overstated).

Sexual Dimorphism

Sexual dimorphism is common in Agelenopsis: females are typically larger-bodied with a fuller abdomen and remain web-centered, while males are usually smaller/slimmer with proportionally longer legs and enlarged palps; the degree of size difference varies among species and populations.

  • Usually smaller body length than females within the same species; more slender abdomen.
  • Enlarged, bulb-like pedipalps in mature males (reproductive structures).
  • More likely to wander away from the funnel web when mature, especially during mating season; often encountered roaming.
  • Often appears leggier/proportionally longer-legged than females.
  • Often larger overall body size and heavier abdomen, especially when gravid.
  • More consistently associated with and guarding/maintaining the sheet-and-funnel web.
  • May show a broader abdomen with more visible abdominal pattern area (chevrons/mottling), though pattern intensity varies by species and individual.

Did You Know?

Size across the genus: roughly ~5-20 mm body length (legspan often ~2-5+ cm), with females typically larger than males.

Their hallmark web is a flat "sheet" leading to a funnel-shaped retreat where the spider hides and rushes out to grab prey.

Many Agelenopsis webs become most visible at dawn when dew outlines the sheet-and-funnel architecture like lace on lawns.

A key family-level ID cue (Agelenidae): noticeably long, tail-like posterior spinnerets that help lay down dense sheet silk.

Life cycle is often about 1 year, but across species and climates many can range ~9-24 months (often overwintering as juveniles).

The name "grass spider" is not one species-it's a common name applied to multiple Agelenopsis species that look very similar.

Males commonly leave their webs when mature and wander in search of females, which is why they're often noticed indoors late summer/fall.

Unique Adaptations

  • Elongated posterior spinnerets (a hallmark of Agelenidae) that aid efficient production and placement of sheet web silk.
  • A funnel retreat that doubles as a shelter and an ambush "control room," letting them respond instantly to prey vibrations while staying protected.
  • High-speed running and quick turning, well-suited to hunting across a broad silk surface instead of relying on sticky capture threads.
  • Vibration-based prey detection tuned to a large, tensioned sheet web-effective for intercepting walking and hopping insects common in grasses.
  • Behavioral flexibility in web placement (from natural grass tussocks to human-made edges), helping different species persist in disturbed or urban-adjacent habitats.

Interesting Behaviors

  • Sheet-and-funnel web building in grasses, shrubs, and around structures; web placement varies by species and local habitat (lawns, fields, gardens, building edges).
  • Sit-and-wait predation: the spider stays in the funnel retreat and uses vibration cues on the sheet to locate prey quickly.
  • Rapid pursuit on silk: when prey hits the sheet, they sprint out, bite, and often drag prey back toward the funnel.
  • Web site fidelity: individuals may maintain and repair the same web for extended periods, adding silk and clearing debris as needed.
  • Seasonal roaming by adult males: many males abandon webs to mate, increasing human encounters and road-crossings compared with web-bound females.
  • Defensive retreat: when disturbed, they usually dart into the funnel or drop off the web on a safety line; bite incidents are uncommon and typically defensive.

Cultural Significance

Grass spiders (Agelenopsis) are common lawn spiders in much of North America. Their dew-covered sheet webs show up in mornings and in photos. They are often mistaken for dangerous spiders, so teaching people to tell them apart and their yard pest role is important.

Myths & Legends

Anansi the Spider (Akan/West African folklore) is a clever trickster who uses wit to outsmart stronger beings and sometimes brings stories and wisdom to people. Folks often call many "spider tales" Anansi.

Spider Woman (Hopi and Navajo traditions): a powerful creative figure associated with weaving, teaching, and protection; her web and weaving are used as metaphors for interconnected life and knowledge.

Arachne (Greek mythology): a mortal weaver whose contest with Athena ends in transformation into a spider, linking spiders in general with artistry, weaving, and the origins of web-making.

European household lore about "house spiders" and web-makers: in various traditions, spiders in or near the home can be seen as signs of industry, thrift, or fortune-associations often applied to common funnel-weavers found around buildings.

Naming and natural-history tradition: the genus name Agelenopsis ("resembling Agelena") reflects early taxonomists' focus on funnel-web architecture, embedding web design into the way these spiders are discussed and recognized.

Conservation Status

NE Not Evaluated (IUCN typically assesses species rather than genera; as a group, Agelenopsis spp. are largely not globally assessed, and there is no single genus-wide Red List category). Genus-wide ranges & generalizations (acknowledging diversity among species): Distribution is primarily North America (many species widespread; some may be more localized). Adult body size varies across the genus, roughly ~4-18 mm body length (females commonly larger than males), with legspan varying substantially by species/sex. Lifespan is generally annual (often ~1 year from egg to reproduction), but can extend toward ~2 years in cooler climates or when development is slowed (e.g., overwintering juveniles). Behavior/ecology: most species are sedentary ambush predators that build horizontal sheet webs in grasses, low shrubs, and human-built edges, with a funnel retreat used as a vibration-sensing refuge; prey capture relies on rapid dashes from the funnel onto the sheet. Many species tolerate suburban settings and disturbed habitats, but web-site preferences (grassland vs. shrub edges vs. structures), seasonal timing, and degree of synanthropy vary across species and regions. Reproduction typically involves wandering males searching for females; females produce one or more egg sacs, and juveniles often disperse (sometimes by short-range ballooning) and overwinter. Conservation landscape across the genus: most Agelenopsis are presumed common or locally abundant where suitable vegetation structure exists, but the lack of comprehensive species-level assessments means status can range from likely secure in widespread species to potentially data-deficient or locally vulnerable in range-restricted taxa; local declines can occur where habitat structure is simplified or heavily treated with pesticides.

Has not yet been evaluated against the criteria.

Population Unknown

You might be looking for:

Pennsylvania grass spider

28%

Agelenopsis pennsylvanica

A common Agelenopsis species in eastern North America; often the default species people mean when they say "grass spider."

Western grass spider

16%

Agelenopsis aperta

Well-studied southwestern U.S. species; notable for behavior and variation across habitats.

Agelenidae (funnel-weaver spiders)

14%

Agelenidae

The broader family containing Agelenopsis; many members build sheet webs with a funnel retreat and are sometimes called grass/funnel weavers.

Labyrinth spider

8%

Agelena labyrinthica

A European funnel-weaver sometimes loosely referred to as a grass/funnel-web spider in regional usage.

Life Cycle

Birth 100 spiderlings
Lifespan 14 years

Lifespan

In the Wild
8–24 years
In Captivity
10–36 years

Reproduction

Mating System Polygynandry
Social Structure Solitary
Breeding Pattern Transient
Fertilization Internal Fertilization
Birth Type Internal_fertilization

Agelenopsis spiders are solitary. Both males and females often mate with several partners. Males wander to find web-bound females. Fertilization is internal by male pedipalps. Mating is brief and there is no pair bond.

Behavior & Ecology

Social Solitary Group: 1
Activity Crepuscular, Nocturnal, Cathemeral
Diet Insectivore Small to medium insects that blunder onto the sheet web-especially flies/mosquitoes and other soft-bodied, vibration-producing prey.
Seasonal Hibernates

Temperament

Generally shy and retreat-oriented; rapid dash to funnel when disturbed
Web-territorial toward conspecific intruders; tolerance mainly limited to brief overlaps at high density
Defensive if handled (may bite when pressed), but typically non-aggressive toward humans
Predatory response is vibration-triggered; attack is fast and direct once prey is detected
Seasonal roaming by adult males increases encounters and apparent boldness during breeding periods

Communication

none No true acoustic vocalizations; communication is primarily substrate-borne
web-borne vibrational signaling Prey detection and courtship tapping/plucking patterns
chemical cues/pheromones on silk and draglines Mate location and reproductive status
tactile signaling during courtship and mating Leg contact, web contact
silk deployment and web architecture as indirect signaling Presence/ownership of a retreat and capture sheet

Habitat

Biomes:
Temperate Grassland Temperate Forest Temperate Rainforest Mediterranean Desert Hot Desert Cold Boreal Forest (Taiga) Alpine Wetland +3
Terrain:
Plains Hilly Valley Coastal Riverine Mountainous
Elevation: Up to 10498 ft 8 in

Ecological Role

Generalist insectivorous arthropod predator in ground-layer and low-vegetation habitats (and synanthropic edges), functioning as a common mesopredator.

Suppression of local insect populations (including many nuisance flying insects) Energy transfer from herbivorous/detritivorous insects to higher trophic levels (they are prey for birds, reptiles, amphibians, small mammals, and larger arthropods) Contributes to arthropod community structure via opportunistic predation, including occasional predation on other spiders and predatory insects

Diet Details

Main Prey:
Small flying insects Moths and other small Lepidoptera Ants and other Hymenoptera Small beetles Leafhoppers, planthoppers and other true bugs Crickets and katydids Spiders Small non-insect arthropods +2

Human Interaction

Domestication Status

Wild

Agelenopsis (grass spiders) are wild North American funnel-weavers and have never been domesticated. People mostly meet them by chance near yards, grasses, shrubs, or buildings; they are sometimes kept briefly for school, hobby, or research. Adults are about 5–18 mm long, live about 9–24 months, and make sheet webs with a funnel.

Danger Level

Low
  • Bites are uncommon and typically occur only if trapped against skin; effects are usually localized pain, redness, itching, and mild swelling, with severity varying by individual sensitivity.
  • Secondary infection risk if a bite/scratch is not cleaned (rare).
  • Non-medical nuisance: conspicuous sheet-and-funnel webs around vegetation and building edges; occasionally spiders wander indoors, especially during mating seasons.

As a Pet

Not Suitable as Pet

Legality: Generally legal and unregulated in many U.S./Canadian jurisdictions as a non-protected native invertebrate, but rules can vary by state/province/park/land-management area; collecting from protected lands may be illegal, and shipping/transport across borders may require permits. Always check local regulations.

Care Level: Moderate

Purchase Cost: Up to $20
Lifetime Cost: $20 - $150

Economic Value

Uses:
Ecosystem services (insect predation) Pest management support (natural control around homes/gardens) Education/outreach (teaching arachnid behavior and webs) Research (behavior, silk/web architecture, ecology)
Products:
  • natural reduction of small insect populations in lawns/gardens and around structures
  • live/specimen use for classroom demonstrations of funnel webs and predation behavior
  • ecological data for biodiversity monitoring (presence/abundance in habitats, including urban edges)

Relationships

Related Species 7

Desert grass spider Agelenopsis aperta Shared Genus
Pennsylvania grass spider Agelenopsis pennsylvanica Shared Genus
Potter grass spider Agelenopsis potteri Shared Genus
Utah grass spider Agelenopsis utahana Shared Genus
European labyrinth spider Agelena labyrinthica Shared Family
Giant house spider
Giant house spider Eratigena atrica species complex Shared Family
Barn funnel weaver Tegenaria domestica Shared Family

Ecological Equivalents 4

Animals that fill a similar ecological role in their ecosystem

Wolf spiders Lycosidae Often occur in the same grassy or ground-layer habitats and prey on similar insects, but hunt actively rather than using a sheet-and-funnel web, representing a functional niche overlap as mid-sized terrestrial insect predators.
Nursery web and fishing spiders Pisauridae Share a general role as generalist insect predators in vegetation and near structures, but differ in strategy: active hunting and nursery behavior rather than building funnel retreat webs.
Sheet weavers Linyphiidae Also build horizontal, sheet-like webs in low vegetation. They are typically much smaller and construct different web architectures, but overlap in microhabitat and prey-capture mode (web-based capture of small flying and vegetation-dwelling insects).
Other funnel weavers Agelenidae They have a very similar web form (a sheet leading to a retreat) and a similar prey base; many are found around buildings and landscaping where Agelenopsis also occurs.

Types of Grass Spider

7

Explore 7 recognized types of grass spider

Pennsylvania grass spider Agelenopsis pennsylvanica
Desert grass spider Agelenopsis aperta
Potter grass spider Agelenopsis potteri
Utah grass spider Agelenopsis utahana
Grass spider
Grass spider Agelenopsis naevia
Grass spider
Grass spider Agelenopsis longistyla
Grass spider
Grass spider Agelenopsis oregonensis

Grass spiders are often found mainly in the grass, as you can determine by their name. But they might wander off to other places. They are one of the 1,200 funnel-web spider species that create a blackhole-shaped webs through their large spinnerets. You will often find these webs more than you will find the grass spider.  

Grass Spider Species, Types, and Scientific Name

Grass spiders are known as the Agelenopsis by scientists. It was first described in 1869 and is Greek in origin. The term Agelenopsis consists of “Agelena”, which is a genus also known as Eurasian grass spiders, and “opsis”, which means “to look like”. It belongs to the family Agelenidae and the order Araneae.

It is often confused with the wolf spider and the hobo spider, because of the patterns on its head region. You will spot on either side of the midline two black lines that are slightly lighter and thinner than those on a wolf spider. Moreover, the abdomen of the grass spider has a series of dark chevrons, which are lighter than on wolf spiders. The grass spider contains venom, but with such small fangs, they are not dangerous to humans. 

The grass spider has a few common names around the world. They are funnel web spiders, ground spiders, sheet web spiders, and funnel weavers. There are 14 known species of grass spiders.

They are:

  • Agelenopsis actuosa 
  • Agelenopsis aleenae 
  • Agelenopsis aperta 
  • Agelenopsis emertoni 
  • Agelenopsis kastoni 
  • Agelenopsis longistyla 
  • Agelenopsis naevia 
  • Agelenopsis oklahoma 
  • Agelenopsis oregonensis 
  • Agelenopsis pennsylvanica 
  • Agelenopsis potteri 
  • Agelenopsis riechertae 
  • Agelenopsis spatula 
  • Agelenopsis utahana 

Appearance: How To Identify the Grass Spider?

Funnel Weaver Spider waiting for prey in web in garden

Funnel weaver spider, or grass spider, waiting for prey in web in garden.

Eggs

The eggs are in form of a sac that is laid by the female during the spring season. But the female grass spider dies shortly after hatching the eggs because of the drop in temperature. The baby spiders hatch after a while and go through eating, mating, and molting to eventually become adult spiders. 

Adult

Grass spiders are about half an inch or three-quarters of an inch long. They exhibit sexual dimorphism, and the females are larger than the males. The females measure up to 0.39 to 0.78 inches while the males are around 0.31 to 0.70 inches long. They weigh just as much as a jumping spider, approximately 3 ounces.

It has a hard shell or carapace that is round in shape and has three distinct bands. Two of them run on either side of the middle band and are darkish brown in color. The middle band, however, is slightly lighter than the other two.

The grass spider is usually yellowish brown in color with chevron patterns that distinguish them from other similar spiders. But they show a mix of different colors on their body. The carapace is yellowish brown in color while the abdomen and the distinct part of the legs are relatively darker in color. The spinnerets are long structures on their abdomen but appear as short tails on the body.

The grass spider’s webs often identify it, rather than its physical appearance. You will find its web placed horizontally and formed as a sheet-like structure ending in a funnel. You can imagine it to resemble a black hole. The sheet extends up to 3 feet, while the funnel may measure up to a foot long.

The funnel portion of the web sits within a shelter that often leads down to the spider’s safe space. This may be a rock or any crevice. Prey may come on this web that sends the signal to the Grass Spider. This trap allows the Grass Spider to pounce on them. 

The web is not that reliable for the spider, because it is not exceptionally sticky. Because of the shape, the prey falls inside the trap. This is why grass spiders are agile. They speed toward their prey and attack them, rather than waiting for the prey to stick to the web.

A grass spider is solitary in nature. You will not find it interacting with other of its species socially unless it is the mating season. But one grass spider may share its habitat with other grass spiders sometimes. Their behavior is mostly nocturnal where they avoid going out to hunt in the daylight to hide from predators. They will hunt and eat their prey at night.

Habitat: Where to Find Grass Spider?

Grass spiders mainly reside in North America. But they were introduced into various countries in Central Asia. Their population size is unknown, but they are in abundance in the northern parts of America. 

If you wish to spot them, you can find them in dirty places in a house. They are not attracted to grime, but this is where their prey resides. Many small insects like ants are usually near food scraps or other dirty areas. Hence, these sites make as good as any place for the grass spiders to come and set up their webs. 

However, this is only a rare instance where a male grass spider may find itself in homes. Otherwise, they are found in lawns, grass, gardens, ornamental plants and trees, along foundations, log piles, under rocks and lawn ornaments, tubs, window wells, and sinks. They tend to hide inside the funnel portion and come out only when there is prey nearby on their web. 

Diet: What Do Grass Spiders Eat?

Grass spiders are carnivorous in nature and more specifically, insectivorous. They are pretty fast in locomoting, which serves as a great hunting technique for the Grass Spiders. 

What Do Grass Spiders Eat?

They eat insects that are smaller than them. This includes insects found in the grass, like moths, crickets, grass bugs, aphids, grasshoppers, etc., or the ones found inside homes like ants. 

What Eats Grass Spiders?

Their predators include lizards, birds, and centipedes.

Prevention: How to Get Rid of Grass Spiders?

Grass Spiders are not particularly dangerous to humans. They carry venom, but that is mostly for their prey. Moreover, they are very shy and not at all aggressive in nature. They may bite a human but only in self-defense or if provoked.

Reported grass spider bites have caused pain, swelling, redness, and itching. These symptoms usually stay with the victim for a time ranging anywhere between one day and ten days. Sometimes, a bacterial infection may occur. There have been no reports of a fatal grass spider bite.

Having said that, they may sometimes inhabit domestic homes. You might only find them due to their webs because they stay hidden in the funnel portion of the web that is situated within a shelter. But if you have small insects, you may find yourself encountering a grass spider infestation too. If that happens, you can opt to do a few things.

  • Clean up leftover food, pet food, crumbs, and scraps around the house. Do not leave them lying around as they attract ants, which will call out the grass spiders.
  • Mow your lawns frequently, because this is where they build large nests.
  • Trim the bushes, hedges, and vegetation around your house and keep them neat to avoid building a grass spider habitat.
  • Use a broom to remove spider webs that will force them to build their nests somewhere else.

Up Next…

Enjoying our spider-related articles? Take a look at a few others.

  • Why Do Plagues Of Snakes And Spiders Follow Floods? – Find out why you see more of them after a flood.
  • 10 Black Widow Facts – You’ve probably heard of these spiders, but do you know how incredible they actually are?
  • Insects Vs Spiders – You can finally find out what the difference is between these two!
View all 261 animals that start with G

Sources

  1. Smiths Pest Management / Accessed August 5, 2022
  2. PSU / Accessed August 5, 2022
  3. MDC / Accessed August 5, 2022
  4. Insect Identification / Accessed August 5, 2022
  5. Western Exterminator / Accessed August 5, 2022
  6. New Mexico Pest Control / Accessed August 5, 2022
  7. Kidadl / Accessed August 5, 2022
Alan Lemus

About the Author

Alan Lemus

Alan is a freelance writer and an avid traveler. He specializes in travel content. When he visits home he enjoys spending time with his family Rottie, Opie.
Connect:

Thank you for reading! Have some feedback for us?


Grass Spider FAQs (Frequently Asked Questions)

No, they are not dangerous. They do have venom, but that is to subdue prey. The most they will do to a human is bite, though their fangs are not penetrable to human skin. So, you will feel itching, redness, and swelling for anywhere between 1 to 14 days if bitten by a grass spider.