Spider Identification Guide

Brown Widow Spider

Appearance:

The brown widow is closely related to the black widow but is slightly smaller and generally lighter in color. Its body color can range from light tan to dark brown or even black, often with shades of gray. Like its more infamous cousin, the brown widow has a distinctive hourglass-shaped marking on the underside of its abdomen—though in this species, the marking is typically a vivid orange or yellow-orange.

The top side of the abdomen often features a mottled or geometric black-and-white pattern, which becomes less pronounced as the spider ages. Brown widows also have pale bands or stripes on their legs, adding to their distinctive look. Perhaps the easiest way to identify a brown widow is by its egg sacs—round and covered in pointed, spiky projections, unlike the smooth, spherical sacs produced by black widows.

Life Cycle

Female brown widows typically live between one and two years, while males live shorter lives. During their lifetime, females can produce approximately 20 or more egg sacs, each containing anywhere from 120 to 150 eggs.

Eggs hatch within 14 to 21 days, and spiderlings remain in the egg sac for several days to several weeks depending on environmental conditions. Once they emerge, the young spiders molt and begin feeding on small prey in the immediate area. While ballooning—a behavior where spiderlings disperse by riding wind currents on silk strands—is observed in some spider species, it is less commonly documented in brown widows.

Brown widow spiders can reproduce year-round in warm climates, making them a persistent presence in Southern California and other temperate regions.

Red-Back Jumping Spider

Appearance:

The red-backed jumping spider is one of the most recognizable jumping spider species in California. These small spiders average about 3/8 of an inch in length, with females typically being slightly larger than males. They have a compact, hairy body and are known for their striking coloration—usually a bright red or orange abdomen and a black cephalothorax and legs. Females often have a central black stripe or marking on the red portion of their back, though patterns can vary.

Red-backed jumping spiders have eight eyes, including a prominent pair of large front-facing eyes that give them excellent vision—among the best of any arthropod. Although they can’t see in 360 degrees, their eye arrangement allows for a wide field of view and sharp depth perception.

These spiders are active daytime hunters that do not spin webs to capture prey. Instead, they rely on their keen eyesight and powerful jumping ability—leaping up to 50 times their body length—to ambush small insects. While they don’t use webs for hunting, they do produce silk to create protective retreats, which they use for resting and for laying eggs.

Life Cycle

Mating begins with a courtship display, where the male performs a zigzag dance and may create vibrations by moving his abdomen. These signals help him communicate with the female and reduce the risk of being mistaken for prey. In some cases, however, the female may still attack or eat the male after mating.

After mating, the female constructs a silken egg sac in her retreat and lays her eggs inside. She remains nearby to guard the sac until the spiderlings hatch. The young spiders emerge as miniature versions of the adults and will molt several times before reaching maturity.

Orb Weaver Spider

Appearance:

The orb weavers (Araneidae) are one of the three largest spider groups. Their webs consist of radiating strands, like spokes of a wheel, and concentric circles. Most orb weavers build their webs vertically, attaching them to branches, stems, or manmade structures. Webs may be quite large, spanning several feet in width and round in shape which is where this family of spiders gets its name. Orb weaver spiders possess eight eyes, arranged in two rows of four eyes each. Despite this, they have relatively poor eyesight and rely on vibrations within their web to alert them to food. Orb weavers have four to six spinnerets, from which they produce strands of silk. Many orb weavers are brightly colored, and have hairy or spiny legs.

Life Cycle

Males are much smaller than females, and after mating may become her next meal. The female waits on or near her web, letting the males come to her. She lays eggs in clutches of several hundred that are cocooned in silken sacs. In areas with cold winters, the female orb weaver will lay a large clutch in the fall and wrap it in thick silk. She will die with the first frost, leaving her babies to hatch in the spring. Orb weavers live, on average, one to two years.

Wolf Spider

Appearance:

Wolf spiders are usually, brown, grey, black or tan, with dark markings (usually stripes). Their coloring is an effective camouflage, helping them catch their prey and keep safe from predators. They range from a quarter of an inch to over an inch long, with males usually smaller than females. They have a distinctive eye arrangement, where the front row is composed of four small eyes of roughly the same size arranged in almost a straight line. The back row is arranged in a V-pattern with the point next to the back row. Wolf spiders have excellent night vision, and primarily hunt in the dark. They are easily detected at night due to their eye shine.

Life Cycle

The males signal their interest to females by waving their pedipalps (short, sensory appendages near their mouths) in special patterns or banging them together. After mating, female wolf spiders lay several dozen or more eggs and wrap them in silk, creating an egg sac. Female wolf spiders carry their egg sacs attached to her spinnerets (silk making organs). If the female loses her egg sac, she will search for it. Females are known to be most aggressive when carrying their egg sacs. After hatching, spiderlings climb on their mother’s back and she carries them around for several days. The baby spiders, then migrate to new territories by the process of ballooning. (Spinning silk threads that catch a friendly breeze, carrying them away.) Male wolf spiders typically live for one year or less, while females can live for several years.

Desert Recluse Spider

Appearance:

The Desert Recluse is found in the Sonoran and Mojave deserts, in the foothills of the lower Joaquin Valley and areas close to the Mexican border. They prefer to live in remote unpopulated areas. These spiders are nocturnal, meaning they only come out at night and they live under rocks and in old animal burrows. The average size of a mature Desert Recluse spider is approximately 1/2 of an inch, with a leg span of 1.5 to 2 inches. Male and female are similar in size. Desert Recluse spiders, and other related recluse spiders, have six eyes arranged in three pairs of two. This is a unique feature, since most spiders have eight eyes. Its’ legs are quite long and almost hairless, and with legs spread outward the spider may have a diameter of less than 1.5 inches. The cephalothorax is round in appearance and the abdomen is narrow and covered with very short hairs. This spider can be yellowish tan to dark brown in color. It is different from other recluse spiders in that it does not have the typical violin marking on its’ abdomen. The dark violin marking will appear on the top of its’ cephalothorax.

Life Cycle

A female Desert Recluse deposits 40 to 50 eggs inside a single silken egg sac. In her life time she will produce 1-5 of these egg sacs. The spiderlings go through their first molt inside the egg sac then hatch out in about two weeks. After emerging, they go through 6 or 7 more molts in the next 7-12 months before becoming adults. Adults live about 1-2 years.

Warning: These spiders may bite! Desert Recluse spiders are normally timid and prey on other insects. Man is not on their menu. If disturbed, they will defend themselves and their bite is venomous. Symptoms of a bite can range from nothing, to a wound that can become life threatening.

This spider is often mis-identified as a deadly “Brown Recluse”. (see below)

Common House Spider

Appearance:

The Common or American House Spider is a nuisance pest and poses no threat to humans. If trapped it may bite. It is aptly named as it is most often found indoors. The adult female of the species is approximately 5-8 mm (3/16 – 5/16 in) in length with a spherical (round) abdomen. Males have elongated abdomens and range from 3.8mm to 4.7mm (1/8 to 3/16th in) in length. These spiders have eight eyes (the 2 lateral pairs almost touch) and their 4th pair of legs has a row of serrated bristles. Both male and female are yellowish brown in color with their abdomens being off white with a few dark stripes meeting at an angle.

House spiders randomly select sites for their tangled webs. Insides homes, these spiders find it hard to survive because of low humidity and few insects they consider food. Outside they can be found around windows and in eaves, especially where a light source attracts their prey.

Life Cycle

Female common house spiders are usually the initiators of mating activity and are not aggressive towards the male. It is not unusual for male and female house spiders to live together on the same web. Mating may occur at any time of year. Common house spiders deposit as many as 250 eggs into a silken sac. These sacs are brownish in color and shaped like a flask. Females produce up to 17 of these sacs during their lifetime, resulting in more than 4,000 eggs. Within a week, spiderlings hatch. Adult spiders may survive up to a year or more.

Creatures misnamed as Daddy longlegs include:

The Crane Fly

Cellar Spiders

California Ebony (Black) and San Diego Bronze Tarantulas

Appearance:

Solitary hunters, these tarantulas, both about 2 inches in length, live in holes in the ground, or occasionally amid rocks, on dry, well-drained grass-covered hillsides or oak-filled woodlands and even desert environs. Tarantulas have poor vision, so they depend on the silk they deposit on the ground around their burrows to send a vibration, signaling that prey is within their reach. Their basic diet consists of beetles, grasshoppers, lizards, mice, scorpions, spiders and other insects. Tarantulas have eight legs, two pedipalps (claws), 8 eyes and are covered with hairs (used to assess their environment since their eyesight is poor and it serves as a defensive mechanism). These spiders have two large, prominent fangs for injecting venom into prey. The venom not only helps to immobilize prey, but also liquefies and digests the soft insides. The Ebony Tarantula is varied shades of black and grey whereas the Bronze is dusky brown to almost black.

Life Cycle

In the fall, after heavy rains, mature males emerge from their burrows seeking females. Male tarantulas take 7 to 10 years to reach maturity (mating age). Males create a ball of webbing upon which they deposit a small amount of sperm. They carry this ball in their pedipalps as they go looking for a female. When they find a female’s burrow, they tap on the silk lines outside of the female’s burrow to get her attention. If the female shows interest, the sperm will be deposited, and the male will try to escape quickly. Most males, even if they are not eaten by the females, die within 2 or 3 months. Female tarantulas produce an egg sac containing anywhere from two to more than 100 eggs. They lay their eggs within their burrow, in an area lined with their silk. Then cover them with more spider silk to form an egg sac. She will guard her eggs until they hatch. Female tarantulas have been known to live up to 25 years.

Brown Recluse Spider

Appearance:

These typically brown to grayish colored spiders have a body length of about 3/8″ inch (but can grow larger), with very long legs. They have six eyes arranged in pairs (dyads) with one middle pair and two side pairs. These spiders usually have markings on the top side of their cephalothorax, with a black line coming from it that looks like a violin with the neck of the violin pointing to the rear of the spider, resulting in the nicknames of fiddle back spider, brown fiddler, or violin spider.

Life Cycle

The female will lay 40 to 50 eggs in a silken casing, producing 1-5 casings during her lifetime. The spiderlings hatch and go through one molt inside the egg case before emerging into the world. After emerging, the instars go through 6-7 more molts in the nest during the next 7 to 12 months before becoming adults. The adults live 1-2 years.