Denver’s mix of high-altitude climate and urban development creates the perfect habitat for spiders in Denver Colorado. You might spot an eight-legged visitor crawling across your basement floor, building webs in your garage, or hunting in your garden.
While discovering spiders can trigger alarm, understanding which species share your space helps you respond appropriately. Most spiders you’ll encounter are harmless hunters that control pest populations, though a few warrant caution and professional removal.
This guide walks you through 20 spider species common to Denver, from the dangerous black widow to beneficial jumping spiders.
You’ll learn how to identify each species, understand their behavior patterns, and know when to call pest control versus when to simply let nature’s pest managers do their work.
1. Black Widow Spider
The black widow spider (Latrodectus hesperus) stands as Denver’s most dangerous spider species. Female black widows display shiny, jet-black bodies with the unmistakable red hourglass marking on their abdomen’s underside. They measure up to 1.5 inches long including legs, while males are much smaller, paler, and pose no threat to humans.
These spiders construct irregular, tangled webs in dark, undisturbed locations. You’ll find them in window wells, crawl space entrances, garage corners, woodpiles, and beneath outdoor furniture. Female black widows rarely leave their webs and bite only when they feel trapped or their web is directly disturbed.
Black widow venom affects the nervous system and can cause serious symptoms including muscle pain, cramping, nausea, difficulty breathing, and elevated blood pressure. While bites are medically significant and require immediate medical attention, fatalities remain extremely rare with modern treatment.
Important Note: Black widows are non-aggressive and will attempt to flee before biting. Most bites occur when people unknowingly press against a hidden spider while moving items in storage areas or reaching into dark spaces without looking first.
If you spot a black widow on your property, keep your distance and contact professional pest control. Shine a flashlight before reaching into dark corners, wear gloves when working in areas where black widows hide, and teach children to recognize and avoid these distinctive spiders.
2. Brown Recluse
The brown recluse (Loxosceles reclusa) is rare in Denver but occasionally reported, typically arriving via travel or shipping rather than establishing permanent populations. Colorado’s cold winters and dry climate don’t support brown recluse populations, though many spiders are misidentified as this species.
True brown recluses display pale brown or buckskin coloring with a distinctive violin-shaped marking on their back behind the head. Most importantly, they have three pairs of eyes arranged in a semicircle, unlike most Colorado spiders which have four pairs. Their body length measures 6-20mm, with long, uniformly colored legs.
Brown recluse venom contains necrotic properties that can damage skin tissue. However, Dr. Paula Cushing from the Denver Museum of Nature & Science notes that the vast majority of recluse spider bites are asymptomatic. Serious reactions are uncommon, though when they occur, they can produce slow-healing wounds requiring medical attention.
Key Insight: Funnel weaver spiders and woodlouse hunters are the two spider groups most commonly misidentified as brown recluses in Colorado. These harmless species share similar brown coloring but lack the violin marking and have four pairs of eyes instead of three.
If you believe you’ve found a brown recluse, try to safely capture or photograph it for professional identification. The Denver Museum of Nature & Science can identify specimens. Given their rarity in Denver, what you’ve likely found is a harmless brown spider species.
3. Woodlouse Hunter
The woodlouse hunter (Dysdera crocata) earned its common name from its preferred prey: pill bugs, also called roly-polies. This distinctive spider features a reddish-orange body with pale yellowish legs, making it relatively easy to identify. Adults measure 9-15mm in body length with notably large fangs relative to their size.
You’ll encounter woodlouse hunters under logs, rocks, bricks, boards, and in areas where pill bugs congregate. They’re nocturnal hunters that spend daylight hours hidden in moist, dark locations. These spiders don’t build webs but actively hunt their hard-bodied prey at night.
The large fangs help woodlouse hunters pierce the tough exoskeletons of pill bugs and similar prey. While capable of biting humans, these spiders are non-aggressive and bites occur only when the spider is directly handled. Any bite would be painful due to the fang size but produces only localized effects similar to a bee sting.
These beneficial spiders help control pill bug populations that can damage garden plants. Unless you’re actively turning over rocks, logs, or moving building materials, encountering a woodlouse hunter is relatively uncommon. They prefer outdoor environments and rarely venture inside homes.
4. Wolf Spider
Wolf spiders (Hogna carolinensis and related species) rank among Denver’s largest and most frequently encountered spiders. Multiple wolf spider species inhabit Colorado, all sharing similar hunting behaviors and intimidating appearance. These robust spiders measure 0.6 to 2 inches in length, with females significantly larger than males.
Their coloring ranges from dark brown to gray with pale or yellowish markings creating distinctive patterns. Many people mistake large wolf spiders for tarantulas due to their size and hairy appearance. However, wolf spiders have a more streamlined body shape and are commonly found throughout Denver, while tarantulas primarily inhabit southern and eastern Colorado.
Unlike web-building spiders, wolf spiders are active ground hunters with excellent eyesight. They chase down prey with impressive speed using their powerful legs. During the day, they hide in shallow burrows or under objects, emerging at night to hunt. Female wolf spiders carry their egg sacs attached to their spinnerets, and after hatching, baby spiders ride on their mother’s back for several days.
Wolf spider bites cause minor pain and swelling similar to bee stings. Their venom isn’t medically significant for humans, though their large fangs mean bites are noticeable. These spiders bite only when handled or cornered, preferring to flee when disturbed.
Pro Tip: Wolf spiders are beneficial predators that consume numerous pest insects around your home. If you find one indoors, safely capture it under a container and release it outside rather than killing it. They help maintain natural pest control in your yard and garden.
5. Jumping Spider
Jumping spiders (Phidippus audax, Phidippus johnsoni) are the compact, curious spiders you’ll notice on sunny walls, windowsills, and outdoor surfaces. These small arachnids typically measure 8-15mm in length and are instantly recognizable by their stocky build, short legs, and remarkably large forward-facing eyes.
Phidippus audax, the bold jumping spider, displays black coloring with white spots and sometimes orange or red markings near the rear of the abdomen. Phidippus johnsoni, Johnson’s jumping spider, is one of Colorado’s largest jumping species with bright red coloring on the abdomen and distinctive iridescent green chelicerae (mouthparts).
Their jerky, start-stop movement pattern and remarkable jumping ability set them apart from all other spiders. Some species can leap up to 50 times their own body length to pounce on prey or escape danger. These daytime hunters don’t build webs for catching prey but actively stalk insects across surfaces using their superior vision.
Jumping spiders often turn to watch you when you approach, which reflects their visual acuity rather than aggression. They’re among the most intelligent spiders, capable of planning complex hunting strategies and even solving simple puzzles in laboratory settings.
These spiders are completely harmless and beneficial around your home. They consume flies, mosquitoes, and other nuisance insects. Many people enjoy watching these personality-filled spiders go about their hunting activities on windows and outdoor walls.
6. Orb-Weaver Spider
Orb-weaver spiders (Araneus spp., Argiope spp.) create the classic circular webs that come to mind when most people picture spider webs. This diverse group includes many species varying in size and coloring, but all share the distinctive wheel-shaped web architecture.
Common orb-weavers in Denver include various Araneus species displaying browns, grays, and mottled patterns. The cat-faced spider (Araneus gemmoides) is particularly common, named for the two horn-like projections on its large abdomen. These spiders are most active at night when they repair and rebuild their webs.
You’ll find orb-weaver webs stretched between plants, across pathways, around outdoor lights, in garden areas, and between fence posts. The spiders typically position themselves in the web’s center or hide in nearby foliage, monitoring web vibrations that signal trapped prey.
Most orb-weavers are harmless and provide excellent natural pest control by catching flying insects. They help reduce mosquito and fly populations around your property. While their large webs can be inconvenient when you walk through them accidentally, these spiders pose no danger.
7. Banded Garden Spider
The banded garden spider (Argiope trifasciata) is a specific orb-weaver species notable for its striking appearance and elaborate webs. Females grow substantially larger than males, reaching up to 25mm in body length. Males remain quite small at 5-9mm and are rarely observed.
This spider displays silvery coloring with dark and yellow banding on both the body and legs. Their legs often appear to be arranged in pairs, making it seem like the spider has four thick legs rather than eight thin ones. Their webs frequently include a distinctive zigzag pattern of thick white silk called a stabilimentum running through the center.
Banded garden spiders prefer garden settings and low vegetation where they spin their webs near ground level. True to their name, they’re most common in late summer and early fall among shrubbery and flowering plants. They position themselves head-down in their webs, waiting for prey to become entangled.
An unusual behavior of this species is keeping its dark underside pointed south, believed to help absorb additional solar energy for metabolism. When disturbed, they may shake their entire web vigorously to appear more intimidating.
Despite their impressive size, banded garden spiders are completely harmless. They focus exclusively on catching and eating insects, making them valuable allies in controlling garden pests. Their venom has no medical significance for humans.
8. Cross Orb-Weaver
The cross orb-weaver (Araneus diadematus) gets its name from the distinctive cross-like pattern of white dots on its abdomen. This medium to large orb-weaver displays variable coloring ranging from pale yellow-brown to dark brown or reddish, always featuring the characteristic white cross marking.
Females measure 6-18mm in body length while males are smaller at 5-13mm. Their bulbous abdomens and relatively short legs give them a compact appearance compared to other orb-weavers. The cross pattern makes identification relatively straightforward once you know what to look for.
These spiders build classic orb webs in gardens, between bushes, on building corners, and in other locations with good insect traffic. They’re most active from late summer through fall when mature adults are abundant. Cross orb-weavers often construct webs near one another, though they maintain individual territories.
Cross orb-weavers are harmless and beneficial spiders that help control flying insect populations. They consume mosquitoes, flies, gnats, and other small flying pests. While they can bite if roughly handled, bites produce only minor, temporary irritation.
9. Funnel Weaver Spider
Funnel weaver spiders (Agelenopsis spp.) create the distinctive flat, sheet-like webs with funnel-shaped retreats that you’ll notice in grass, bushes, building corners, and between rocks throughout Denver. These common brown spiders measure 10-20mm in body length with long legs and spinnerets extending from their abdomen.
The funnel serves as the spider’s hiding spot and retreat center. The spider waits inside this tube-like structure monitoring vibrations from the sheet web spread in front. When prey lands on the sheet, the spider rushes out at remarkable speed, grabs it, and quickly retreats back into the funnel.
Funnel webs become particularly noticeable in early morning when dew collects on the silk, revealing intricate sheet patterns across lawns and vegetation. Unlike sticky orb-weaver webs, funnel webs aren’t adhesive. Instead, the dense silk slows insects down, allowing the fast-moving spider to capture them.
Common Mistake: Many people mistake funnel weaver spiders for brown recluses due to their similar brown coloring and size. However, funnel weavers have darker coloring with black markings on the abdomen, lack the violin marking, have four pairs of eyes instead of three, display striped legs, and move considerably faster than recluses.
These spiders are harmless and beneficial, helping control insect populations around your property. Indoor migrations increase in late summer and early fall as mature spiders wander searching for mates. Simply relocate any indoor spiders outside rather than killing these helpful hunters.
10. Grass Spider
Grass spiders (Agelenidae family) are closely related to funnel weavers and share similar web-building behavior. These spiders are particularly common in lawns, meadows, and grassy areas throughout Denver. They measure 10-20mm in body length with light to dark brown coloring featuring distinctive stripes running down their bodies.
Like funnel weavers, grass spiders build flat sheet webs with funnel retreats. Their webs are typically found in grass, low vegetation, and along the ground rather than elevated positions. Multiple grass spider webs can blanket lawn areas, becoming strikingly visible after morning dew or light rain.
These spiders are incredibly fast runners, which helps them catch prey on their non-sticky sheet webs. They detect prey through web vibrations and rush out to grab insects before they can escape. Grass spiders rarely enter homes but may occasionally wander indoors during mating season in late summer.
Grass spiders are harmless and provide natural pest control by consuming various insects. Their presence in lawns indicates healthy insect populations and good habitat diversity. Bites are extremely rare and produce only minor, temporary effects if they occur.
11. Long-Bodied Cellar Spider
The long-bodied cellar spider (Pholcus phalangioides) is the delicate, wispy spider you’ll find hanging upside down in corners throughout Denver homes. Often called “daddy long-legs spiders,” these spiders feature extremely long, thin legs and small bodies measuring just 7-10mm in length, though their leg span can exceed 50mm.
Their pale yellow-brown to light gray coloring and fragile appearance lead to frequent confusion with harvestmen (which aren’t spiders). You can distinguish cellar spiders by their distinct body with two sections and eight legs attached to the body, whereas harvestmen have one body section.
These spiders build loose, irregular webs in dark, quiet areas like basements, garages, closets, and ceiling corners. When their web is disturbed, cellar spiders perform distinctive behavior: they vibrate rapidly, making themselves appear blurry and harder for predators to catch. This defensive strategy earned them the alternate name “vibrating spiders.”
Key Insight: Cellar spiders are beneficial predators that actively hunt and kill other spiders, including dangerous species like black widows. Their presence in your home actually provides protection against more concerning spiders. Their venom is not harmful to humans.
Leave these beneficial spiders undisturbed in areas where they don’t bother you, like basement corners or garage ceilings. If you need to remove them from living spaces, simply vacuum up the spider and web. They pose absolutely no threat and provide valuable natural pest control.
12. Common House Spider
The common house spider (Parasteatoda tepidariorum) is exactly what its name suggests—the most frequently encountered spider inside Denver homes. These small spiders measure 5-8mm in body length with yellowish-brown to dark brown coloring featuring a distinctive herringbone pattern on their abdomen.
House spiders build tangled cobwebs in room corners, along ceilings, around windows, behind furniture, and in other undisturbed indoor spaces. Unlike orb-weavers that rebuild daily, house spiders maintain their webs for extended periods, adding to them over time. Old webs accumulate dust, creating the classic “cobweb” appearance.
These spiders are completely harmless household inhabitants that feed on flies, mosquitoes, gnats, and other small insects that enter your home. While they can bite if provoked, bites are extremely rare and cause only minor, temporary irritation. Their presence helps control indoor insect populations naturally.
Regular cleaning removes cobwebs and discourages house spider populations from reaching nuisance levels. However, a few house spiders in storage areas or basements actually benefit your home by catching pest insects. They’re far more beneficial than problematic.
13. False Widow Spider
The false widow spider (Steatoda grossa) resembles the black widow enough to cause concern, though it’s significantly less dangerous. These spiders measure 7-14mm in body length with shiny brown to purplish-black coloring and pale markings on their bulbous abdomens—but crucially, no red hourglass.
False widows build irregular cobwebs in dark, sheltered locations similar to true black widows: garages, sheds, under outdoor furniture, in woodpiles, and inside homes near windows, in basements, or in storage areas. They’re nocturnal and spend days hidden in silk retreats near their webs.
While false widow bites aren’t medically significant like black widow bites, they can cause more discomfort than most harmless spiders. You might experience localized pain, redness, and swelling lasting several hours to a few days. Rarely, some individuals experience more pronounced reactions including headaches or mild nausea.
Distinguishing false widows from black widows is important for appropriate response. Look for the absence of the red hourglass marking and the generally lighter, brownish coloring. False widows are shy and non-aggressive, preferring to flee when disturbed rather than bite.
14. Ground Spider
Ground spiders (Gnaphosidae family) are the fast-moving nocturnal hunters you might glimpse scurrying across floors or walls at night in Denver homes. These spiders typically measure 8-15mm in length with flattened bodies that help them squeeze into tight crevices. Their coloring ranges from tan to dark brown or gray, often with a somewhat velvety appearance.
During daylight hours, ground spiders hide under stones, bark, leaf litter, or in cracks and crevices. They emerge after dark to actively hunt prey on the ground level rather than building webs. Their speed and agility make them effective predators of various insects and other small arthropods.
Inside homes, you’ll encounter ground spiders in basements, garages, and along baseboards. They enter buildings through gaps under doors, cracks in foundations, or openings around utility lines. Once inside, they continue their nocturnal hunting patterns, helping control household insect populations.
These spiders are beneficial and harmless. While they can bite if roughly handled, such incidents are uncommon. Any bite would cause only minor, temporary discomfort similar to a bee sting. They provide natural pest control by consuming various household insects.
15. Crab Spider
Crab spiders (Thomisidae family) earn their name from their crab-like appearance and sideways walking movement. These ambush predators hold their front legs extended sideways, ready to grab passing prey. They measure relatively small, typically 4-10mm in body length.
Their coloring varies dramatically based on species, with many displaying remarkable camouflage abilities. Some crab spiders can gradually change color over several days to match flowers or bark where they hunt. Common colors include white, yellow, pink, green, and various browns matching their preferred hunting locations.
You’ll find crab spiders waiting motionless on flowers, leaves, bark, fence posts, and building surfaces throughout Denver. They don’t build webs but instead ambush insects that come within reach. Their patient hunting strategy makes them highly effective predators despite their small size. In gardens, they’re particularly common on flowering plants where they hunt pollinating insects.
Crab spiders are harmless to humans and beneficial for gardens. They consume aphids, flies, bees, and other insects that visit flowers. Their camouflage makes them nearly invisible until you look closely. Even when handled, these spiders rarely bite, and any bite would produce only minor, temporary irritation.
16. Nursery Web Spider
The nursery web spider (Pisaurina mira) demonstrates remarkable maternal care that distinguishes it from most spider species. Females measure 12-16mm while males are slightly smaller, with brown or tan coloring featuring lighter central stripes running along their bodies.
These spiders are active hunters that don’t build prey-catching webs. Instead, they roam vegetation hunting insects during daytime hours. The “nursery web” name refers to their unique reproductive behavior: females carry egg sacs in their chelicerae (mouthparts) until shortly before hatching, then build a special silk tent to protect emerging spiderlings.
You’ll encounter nursery web spiders in gardens, lawns, parks, and areas with vegetation or ground cover throughout Denver. They’re sometimes mistaken for wolf spiders due to similar coloring and hunting behavior, but wolf spiders attach egg sacs to their spinnerets while nursery web spiders carry them in their jaws.
The protective silk nursery that mothers construct represents impressive parental investment. The mother guards this structure until her offspring disperse, often not eating during this protective period that can last several days.
These spiders are harmless and beneficial for controlling garden insects. While they can bite if handled roughly, such incidents are rare and produce only minor, temporary discomfort. Their presence in gardens indicates healthy ecosystems with sufficient insect prey populations.
17. Goldenrod Crab Spider
The goldenrod crab spider (Misumena vatia) is a specific crab spider species notable for its color-changing ability and preference for flowers. Females measure 7-11mm while males are much smaller at 2-4mm. Colors range widely based on species and individual, with common colors including white, yellow, pink, and green.
This species is particularly famous for its ability to change color between white and yellow over several days to match the flowers where it hunts. This remarkable camouflage helps them ambush pollinating insects that visit flowers. They’re most commonly found on goldenrod, daisies, sunflowers, and other composite flowers.
Goldenrod crab spiders don’t build webs but wait motionless on flower petals with their front legs spread wide. When a bee, butterfly, or fly lands on the flower, the spider strikes quickly, injecting venom that immobilizes the prey. They can capture insects much larger than themselves, including honeybees.
These spiders are completely harmless to humans and too small to bite effectively. While they do hunt beneficial pollinators, they’re part of natural ecosystem dynamics and don’t significantly impact pollinator populations. Their presence indicates healthy flower gardens with diverse insect activity.
18. Sheet Web Spider
Sheet web spiders (Linyphiidae family), also called money spiders or dwarf spiders, are among the smallest spiders you’ll encounter in Denver, typically measuring just 2-4mm in body length. Their diminutive size means they’re often overlooked, though their webs are more noticeable than the spiders themselves.
These spiders create horizontal sheet webs with knockdown threads above them. The structure works cleverly: flying insects hit the upper threads, fall onto the sheet below, and get trapped. The spider waits underneath the sheet and pulls prey through to consume it.
You’ll find sheet webs in grass, low vegetation, between branches, and sometimes indoors near windows or in corners. The webs appear particularly striking in morning dew, revealing countless tiny sheets glistening across lawns and gardens. In favorable environments, sheet web spider populations can reach remarkable densities with hundreds of webs per square meter.
Sheet web spiders are completely harmless and beneficial. They’re far too small to bite humans effectively, and their role in controlling tiny flying insects makes them valuable ecosystem members. Their presence indicates healthy insect populations in your yard.
19. Western Parson Spider
The western parson spider (Herpyllus ecclesiasticus) gets its common name from the white markings on its abdomen that supposedly resemble a parson’s cravat or clerical collar. These medium-sized spiders measure 8-15mm in body length with dark brown to black coloring and the distinctive white or light-colored marking on the abdomen.
Parson spiders are ground-dwelling hunters that don’t build webs. They’re nocturnal and spend daylight hours hiding under rocks, bark, leaf litter, or inside buildings in dark corners. At night, they emerge to actively hunt insects and other small prey across surfaces.
Inside Denver homes, you’ll most often encounter parson spiders in basements, garages, and along baseboards. They enter through cracks and gaps seeking shelter and following prey. Their fast movement when exposed to light often startles homeowners, but this reflects their natural desire to return to darkness rather than aggression.
Pro Tip: Parson spiders are beneficial predators that help control household insects including silverfish, ants, and other small arthropods. While they can bite if handled, bites are uncommon and produce only minor, temporary effects similar to a bee sting.
If you find parson spiders indoors, simply capture them under a container and release them outside. Reducing indoor hiding spots and sealing entry points helps prevent their presence inside while allowing them to continue their beneficial hunting activities outdoors.
20. Tarantula
Tarantulas (Aphonopelma coloradanum), specifically the Colorado tan tarantula or Colorado chocolate brown tarantula, are found mostly in southern and eastern Colorado rather than the Denver metro area itself. However, occasional sightings occur in outlying areas, making them worth understanding.
Female tarantulas display thick, bristly tan or brown hair covering a stocky body that can reach 3-5 inches in leg span. Males are typically darker with thinner bodies. These impressive spiders spend most of their lives in underground burrows, which they often seal with silk and dirt to regulate temperature and humidity.
During late summer and fall, mature male tarantulas leave their burrows searching for females, sometimes appearing in broad daylight crossing roads or yards. This annual “tarantula migration” attracts wildlife enthusiasts to southeastern Colorado. Female tarantulas can live 20+ years, while males typically die shortly after mating.
Despite their frightening appearance and size, Colorado tarantulas are docile and rarely bite humans. When threatened, they typically display defensive postures, rear up on hind legs, or flick urticating hairs from their abdomen toward the threat. These hairs cause skin irritation and should not be touched.
Important Note: If bitten by a tarantula, the venom produces effects similar to a bee sting—localized pain and swelling but no serious medical consequences for most people. These spiders deserve observation and appreciation from a respectful distance rather than fear or harm. They play important roles in controlling insect populations in their natural habitats.
Comparison: Dangerous vs. Harmless Spiders in Denver
| Feature | Dangerous Spiders | Harmless Spiders |
|---|---|---|
| Species | Black widow (brown recluse extremely rare) | Wolf spider, jumping spider, cellar spider, house spider, most others |
| Bite Symptoms | Neurological effects, muscle cramps, severe pain | Minor pain, slight swelling, temporary irritation |
| Medical Attention | Required immediately | Rarely necessary except for allergic reactions |
| Behavior | Defensive, bite when threatened or trapped | Flee from humans, bite only if roughly handled |
| Common Locations | Window wells, crawl spaces, garages, woodpiles | Varied: walls, ceilings, gardens, lawns, indoor corners |
| Identification Priority | High—learn to recognize black widows | Low—most differences don’t affect safety |
Frequently Asked Questions
Focus on identifying black widows: shiny black bodies with red hourglass markings underneath. These are Denver’s only reliably established dangerous spiders. Brown recluses are extremely rare in Colorado due to cold winters and dry climate—most suspected brown recluses are actually harmless funnel weavers or other brown spiders. If you can’t confidently identify a spider and it resembles a black widow, treat it as potentially dangerous. However, the vast majority of spiders you encounter in Denver—including large, scary-looking wolf spiders—are harmless. When in doubt, photograph the spider from a safe distance and contact pest control for identification.
Wash the bite area immediately with soap and water, apply ice to reduce swelling, and monitor the wound carefully. If you suspect a black widow bite or develop concerning symptoms (increasing pain, spreading redness, muscle cramps, difficulty breathing, neurological symptoms), seek medical attention immediately. Most spider bites from harmless species resolve on their own within a few days with basic first aid. Take photos of the spider if possible, as identification helps medical professionals determine appropriate treatment. Remember that many skin lesions blamed on spider bites are actually bacterial infections or other medical conditions.
Seal cracks and gaps around windows, doors, foundations, and where utility lines enter. Install door sweeps and repair damaged window screens. Reduce outdoor lighting that attracts insects (spider prey), or switch to yellow u0022bug lightu0022 bulbs. Keep woodpiles, debris, and storage items away from your home’s exterior. Inside, reduce clutter where spiders can hide, vacuum regularly to remove webs and egg sacs, and fix moisture issues that attract both spiders and their prey. Regular professional pest control creates a protective barrier that significantly reduces spider entry while addressing the insect populations that attract spiders.
No, funnel weaver spiders are completely different from brown recluses and are harmless. This misidentification happens frequently in Colorado because both are brown. However, funnel weavers have darker coloring with black markings, striped legs, four pairs of eyes (brown recluses have three pairs), and move considerably faster. They also lack the distinctive violin marking on the back that characterizes brown recluses. Brown recluses are extremely rare in Colorado and rarely establish populations here due to unsuitable climate conditions. If you’ve found a brown spider in Denver, it’s almost certainly a harmless funnel weaver, not a brown recluse.
No, many Denver spiders are active hunters that don’t build webs. Hunting spiders include wolf spiders, jumping spiders, ground spiders, parson spiders, and crab spiders that actively pursue prey. Web-building species include orb-weavers, cellar spiders, house spiders, funnel weavers, sheet web spiders, and black widows. Understanding whether a spider builds webs helps with identification and control strategies. Hunters typically enter homes while pursuing prey, while web-builders settle into quiet corners and undisturbed areas. Both types benefit your property by controlling insect populations.
Spider activity peaks during warmer months from late spring through fall, with late summer and early fall showing maximum activity as many species reach maturity. Funnel weavers commonly enter homes during this period searching for mates. Male tarantulas emerge in southeastern Colorado during fall. However, species like black widows, cellar spiders, and house spiders remain active year-round in protected areas like garages, basements, and heated homes. Fall often brings increased indoor spider encounters as spiders seek shelter from cooling temperatures. Regular preventive pest control throughout the year provides better protection than seasonal treatments alone.
