You see a spider crawling through the grass toward you. Can you tell if it’s a wolf spider or grass spider? Most likely you’ll struggle to identify the differences between these two common arachnids. Their range is similar, they eat similar food, and possess almost identical coloring. To the untrained eye, it seems an impossible task to identify a wolf spider vs grass spider. However, if you know where to look you can easily spot the distinguishing features that separate the two species. Whether you count yourself a spider enthusiast or just want to learn some more spider facts, we got you covered. In this article, we’ll compare wolf and grass spiders and discuss 9 key differences that separate them from each other.
Comparing Wolf Spiders and Grass Spiders
Wolf spiders frequently get confused with nursery web spiders. While the two spiders appear similar, this article does not concern nursery web spiders. However, so you can tell them apart from wolf spiders, we’ll provide a brief introduction to nursery web spiders.
Nursery Web Spiders
Nursery web spiders belong to the family Pisauridae. Unlike wolf spiders, they carry their egg sacs with their chelicerae (mouthparts) and pedipalps (sensory organ appendages between the mouth and legs). In addition, nursery spiders’ eyes all look roughly the same size, while wolf spiders’ eyes differ in size.
Grass spiders belong to two genera; Agelenopsis, or the American grass spider, and Agelena, or the Eurasian grass spider. Differences between the species vary ever so slightly. In fact, they appear so similar that Agelenopsis in Greek translates to “to have a similar look to Eurasian grass spiders.” For the purposes of this article, we’ll exclude discussing Eurasian grass spiders. Instead, we’ll focus on American grass spiders, which we’ll refer to simply as grass spiders. That said, we’ve included a short description of the American grass spiders’ Old World relatives.
Eurasian Grass Spiders
First described by Charles Athanase Walcenaer in 1805, Eurasian grass spiders range throughout Europe, Asia, and Africa. Currently, the World Spider Catalog identifies 46 species of Eurasian grass spiders. Like American grass spiders, Eurasian grass spiders build funnel webs to trap their prey. However, while American grass spiders possess two almost parallel lines from their eyes to their abdomens, the lines on Eurasian grass spiders curve irregularly.
|Wolf Spider||American Grass Spider|
|Taxonomy||Family: Lycosidae||Family: Agelenidae|
|Size||10 to 35 mm wide (excluding legs)||10 to 20 mm wide (excluding legs)|
|Color||The color matches their habitat|
Yellow, brown, or gray
Thick black line down the abdomen
|Yellow, brown, or gray|
Light black line down the abdomen
Grasslands, woods, mountaintops, lava tubes, deserts, rainforests
Most do not make permanent homes
Grass and bushes near the ground
Build nests in their webs
|Webs||No webs||Funnel webs, non-sticky|
|Infant Care||Carry eggs on their spinneretsCare for infants several weeks after hatching||Females die before the eggs hatch|
Two eyes larger than others
Arrayed in three rows, with two on top, two in middle, and four on bottom
Eyes arrayed in three rows, with two eyes on top, four eyes in the middle, and two on the bottom
|Mating Ritual||Males often contain bristles on legs or drum legs as a courtship display|
Females may eat prospective mates
|Males may sway their abdomens to release pheromones to attract female|
The 9 Key Differences Between Wolf Spiders and Grass Spiders
Wolf Spider vs Grass Spider: Taxonomy
While both wolf spiders and grass spiders belong to the Arachnida class of insects, they come from different families. Wolf spiders belong to the family Lycosidae, which is the four largest spider family in the world. Their name comes from the Ancient Greek word λύκος, meaning “wolf.” In total, there exist over 2,300 different species belonging to 100 genera. Meanwhile, grass spiders belong to the family Agelenidae. Currently, scientists recognize over 14 species of American grass spiders.
Wolf Spider vs Grass Spider: Size
Both wolf and grass spiders can vary greatly in size. The smallest wolf spiders can measure as little as 3 mm in body size. However, in general, the size of a wolf spider’s body ranges from 10 mm to 35 mm wide. With their lengths, they typically measure 1.5 to 2 inches in length. At their largest, it’s easy to distinguish them from the biggest grass spiders. On average, grass spiders measure between 10 mm to 20 mm in size.
Wolf Spider vs Grass Spider: Color
Wolf spiders and grass spiders both rely on camouflage to avoid predators and sneak up on their prey. Given that they tend to reside in similar habitats, this means that they often exhibit the same coloring. Both wolf and grass spiders range in color from brown to yellow to gray. However, a discerning eye could spot several faint markings unique to each species. For example, wolf spiders frequently possess a thick black line down their abdomen. On the other hand, grass spiders have a much lighter line on their abdomen. In addition, the markings on grass spiders overall look lighter than those on wolf spiders.
Wolf Spider vs Grass Spider: Spinnerets
A spinneret is an organ unique to spiders and a few other insects. It allows spiders to spin silk which they use to create webs. Depending on the spider, spinnerets can range in size from small to large. In regards to wolf spiders, their spinnerets measure smaller than those of most other spiders. This may contribute to the fact that they do not spin webs. On the other hand, grass spiders’ spinnerets generally appear large compared to other spiders.
Wolf Spider vs Grass Spider: Habitat
Wolf spiders and grass spiders occur commonly throughout natural and manmade habitats. They tend to prefer grasslands and forests, but often find their way inside peoples’ homes in search of food. However, while their ranges overlap, wolf spiders create different homes and are more widely distributed. You can find wolf spiders on every continent except Antarctica. Rather than creating webs, they live in burrows in the ground. They also frequently move around and may live in several homes over the course of their lives. Meanwhile, American grass spiders live only in North America, while Eurasian grass spiders range throughout Africa, Europe, and Asia. In addition, they build their nests in funnel webs, which they typically build low to the ground in grass or bushes.
Wolf Spider vs Grass Spider: Web
It’s a commonly held belief that all spiders weave webs. While this is mostly accurate, it does not hold true in every circumstance. For example, wolf spiders do not weave webs. Instead, they live in burrows in the ground and hunt by ambushing and chasing down their prey. They kill by leaping onto their prey and sinking their fangs into their victims, immobilizing them. Grass spiders, on the other hand, act more like typically spiders, building webs for their nests and to hunt. However, unlike most spider webs, grass spiders’ webs are not sticky. Instead, when prey wanders inside their webs, grass spiders will corner and leap on their victim.
Wolf Spider vs Grass Spider: Infant Care
Over the years, adult spiders earned a terrible reputation for their poor caretaking. Male spiders almost never stick around to help rear children and most female spiders lack a mothering instinct. However, wolf spiders differ from many of their kin. Females carry their eggs around on their spinnerets until they hatch, and will then carry their spiderlings on their backs for several weeks until they can take care of themselves. While wolf spiders buck the trend, grass spiders reinforce it. Female grass spiders deposit their eggs into a silk sac that then overwinters. Generally, the females will die before the eggs hatch, and many die still attached to their egg sac.
Wolf Spider vs Grass Spider: Eyes
It’s a well-known fact that spiders possess eight eyes. However, the distribution, size, and ability of the eyes vary greatly between species. On average, spiders do not see well, but wolf spiders have excellent eyesight. Their eyesight helps them to spot and track prey in the dark and to avoid predators. A wolf spider’s eyes are arranged in three rows, with two on top, two in the middle, and four on the bottom. In addition, its middle eyes measure much larger than its other eyes. Like a wolf spider, a grass spider’s eyes lie in three rows. However, its first row contains two eyes, the second four eyes, and the bottom row two eyes. Also, unlike wolf spiders, grass spiders’ eyesight is poor.
Wolf Spider vs Grass Spider: Mating Ritual
Many spider species take part in elaborate and unique mating rituals. These displays often end gruesomely, usually with the female eating the male. In the case of wolf spiders, rituals vary depending on the species. However, a common ritual involves the males drumming their legs on the ground and showing off enlarged bristles on their legs. Meanwhile, male grass spiders prefer to sway their abdomens from side to side during their courtship ritual. These movements cause them to release pheromones in the hopes of attracting a mate.
Frequently Asked Questions on the Differences Between Wolf Spiders and Grass Spiders
Are wolf spiders and grass spiders nocturnal?
Like most spiders, wolf spiders and grass spiders are nocturnal. They hunt and stay active at night, which allows them to sneak up on prey and avoid many daytime predators.
Are wolf and grass spiders endangered?
Due to their widespread distribution, neither wolf spiders nor grass spiders face any threats. At this time, the IUCN has not evaluated either species.