Common United States Spiders
NOT DANGEROUS -
i.e MAY BITE BUT NOT LIFE THREATENING
All spiders can and will bite if in danger or
accidentally touched e.g. in shoes or clothing etc. Any spider bite
can cause a reaction, ranging from a
or wasp sting type bite to those requiring hospitalisation.
Different people react in different ways, so if you see a spider it is best to be cautious and look but do not handle any spider no matter how it is classified.
Web Spinning Spiders
Garden Orb Weaver
- Neoscona crucifera
The family is a large one, including over 2800
species are still being discovered. in over 160 genera
Orb weavers (Araneidae)
are often brightly coloured with rounded abdomens, some with
peculiarly angled humps or spines. However, there is considerable
variation in size, colour and shape in this group. They are often
recognized for building beautiful, large, round webs, on which they
rest, head downward, waiting for prey. The webs consist of a number
of radiating threads crossed by two spirals. The inner spiral begins
in the centre, winds outward, and is made of smooth threads like the
radiating threads. It covers only the central 1/3 of the web. The
outer spiral begins at the edges and winds inward. It is made of
more elastic, sticky threads, coated with a liquid substance. The
life span of these spiders is short, only lasting one season.
Golden Silk Orb Weaver - Nephila clavipes
The Golden Orb Weavers build large,
semi-permanent orb webs. The strong silk has a golden sheen. These
spiders remain in their webs day and night and gain some protection
from bird attack by the presence of a 'barrier network' of threads
on one or both sides of the orb web. Sometimes their strong webs
manage to trap small birds or bats, and the spider will wrap them
and feed upon them. Commoner prey items include flies, beetles,
locusts, wood moths and cicadas. Golden Silk Orb Weavers are large
spiders (body 2-4 cm) with silvery-grey to plum coloured bodies and
brown-black, often yellow banded legs. The males are tiny (5 mm) and
red-brown to brown in colour. This spider belongs to the
Tetragnathidae (longjawed orbweavers) family.
Nephila clavipes is the only species in the Nephila genus that
exists in the USA.
Shamrock Orb Weaver - Araneus trifolium
Orb Weaving Spiders are common spiders
with poor vision which build beautiful, complex-looking webs all over the
world. The shamrock spider is a familiar member of the family and is
distinguished by the markings on its back and black markings on its
Marbled Orb Weaver
- Araneus marmoreus
Orb weavers are known for their bright colours.
They build large, round webs and wait with for their prey with their
head facing down. The abdomen is often rounded. The Marbled Orb
Weaver is common in urban areas and is over 1/2 inch long.
Yellow Argiope - Argiope Aurantia
This lovely spider only has a short life span and
once she has produced one or more (usually no more than 3) brown,
papery egg sacs, she will die. The egg sacs are roughly round in
shape and up to 25 mm in diameter; each contains 300 to 1400 eggs.
She attaches her egg sacs to one side of her web, close to her
resting position at the centre. Each female will watch over her eggs
as long as she can, but will die in the first hard frost, if not
before. The eggs hatch in Autumn ( fall), but spiderlings stay in
the sac during winter and emerge in spring. There is also a
silver argiope which differs in that it has a metallic silver back.
Banded Argiope- Argiope trifasciata
Banded Orb-weaving Spider females have
yellow, white and brown coloured bands across their abdomen
Their head/thorax has silver hair. The legs are hairy, and often banded. The males look the same, but are much smaller
than the female. Banded Orb-weaving Spiders build vertical orb webs and are active both day and night. They make stabilimentum on their
web too, but may not make it like a cross. Banded Argiope are common
throughout most of the US. They can often be found building webs
side by side with the Black and Yellow Argiope but the Banded
Argiope tends to favor slightly drier habitats. The female spins
a silken hemispherical egg sac.
Argiope- Argiope argentata
The male grows to 1/8-1/4" (4-5 mm), and
the female 1/2-5/8" (12-16 mm). They have silvery short hair on
upper surface of female's cephalothorax and 1st abdominal segment.
Most of the abdomen is black to brownish yellow with silver spots.
Underneath is also black to yellow-brown. Legs are blackish brown to
yellow with 2 pale bands and black hair. They make the same zigzag cross strands forming X-shaped mark at centre, measuring to
32" (81 cm) across as the Black and Yellow Argiope. Primarily a spider found in tropical regions of the New World, this
species is able to survive frost only when very young and seldom is
found in the North.
Common House Spider -
builds large webs in the
corners of rooms, under
bedroom furniture and furniture in other rooms, in angles between fences, and
often between stones. They build where they can find the most prey.
They can be found during any season. The colour varies from a dirty
white to almost black. The cephalothorax is yellow brown and the
legs are light yellow with brown or grey rings at the ends and
middle of the joints. The females usually range from 5 to 6 mm long
and the males 3.8 to 4.7 mm . The female lays her eggs in a
brownish, pear shaped cocoon that is 6 to 9 mm in diameter.
Jewel Spiders -
They are also known as spiny orb weavers and
are part of the orb weaving spider family. This spider's body is
very broad and grows to the size of a 20c piece, with its 8 legs
being the length of a pin (fairly short for a spider). Its abdomen
is strikingly coloured with bright
yellow and white and black. Six stout spines (long and sharp) come
from the border of the abdomen.
Spiny micrathena -
Araneidae Micrathena sagittata
The genus Micrathena contains over 100 species
of mostly Neotropical woodland orb-weavers (Levi 1985). M. gracilis
is found in dense deciduous forests in eastern North America south
to Costa Rica. Males do not construct webs after attaining sexual
maturity. The female’s web is a small orb, 3.0 – 7.5 inches in
diameter, typically three to seven feet above the ground in the
Venusta Orchard Spider
The male growsato 1/8" (3-4 mm), and
the female 1/4-3/8" (5-8 mm). Its cephalothorax is
yellowish green, striped with brown along sides. The abdomen is silvery
above with dark stripes, sides yellow with red spot near tip and red
spot underneath. This spider clings below its web or to a nearby twig until prey
blunders into the web and shakes it. They live in Maine to
Florida, west to Nebraska and Texas.
The female Bolas spider is
inactive during the day, although she can often
be found in fairly exposed places. The male is
much smaller than the female. Shortly after
dusk, the spider lowers herself on silk threads,
spins a silk line with a sticky blob on the end
of it and swings it to catch the moths or other
insects that have been attracted by
chemicals. The spider gets its name from the
bolas (ball-on-a-string) weapon used by Eskimos
and South American Indians.
Nursery Web Spider -
These spiders resemble the Wolf
Spiders (Lycosidae), but have a different eye pattern. Pisaurids
have their eyes arranged in 2 rows, the posterior row slightly
recurved, the median eyes in the second row slightly (if any) larger
than the others. (Wolf spiders have eyes arranged in 3 rows). The
egg sac is carried by the female under her
held there by her
Before the eggs hatch, the female attaches the sac to a plant and
then bulds a web around it -- and stands guard nearby. The Pisaurids
forage for their food and build webs only for protecting their
young. Photo - Sue Taylor
Southern House Spider -
The Southern House Spider is
relatively large and has a distinctive flat, tangled web. It is
common throughout Florida and much of the southern United States in
human populated areas. Males of this species are often mistaken for
brown recluse spider, Loxosceles reclusa, because of
their colour and general shape. Southern house spiders are not known
to have a dangerous bite. However, some cases reportedly caused the
victims pain and swelling for a few days.
Daddy Long Legs
People often confuse the Daddy Long
Legs with the long-legged
(Phalangium opili)which are also
called Daddy Long Legs but if you look closely at the
Harvestman you can see that its head, thorax and
abdomen is fused, therefore it is not really a spider.
Pholcus phalangioides is
found world wide. Their webs are messy structures
where the spider resides on the lower side hanging downwards.
Anything that touches the net is attacked and taken for prey if it's
not too big. They feed on insects but are also known to invade other spider's webs and attack the original
inhabitants. They then use their web to catch prey. Daddy Long Legs
have a reputation for being the most venomous spider, probably because they have been know to kill Black Widows and Tegenaria
species, however this has not been proven. Daddy-Long-Legs spiders
have venom glands and tiny fangs and
while commonly thought not to bite humans, have been
reported as doing so.
Weaver Spider - Agelenopis
Funnel Weaver Spiders are often
mistaken for Wolf Spiders but the Funnel Weavers construct large,
flat, horizontal webs of non sticky silk and Wolf Spiders do not
spin webs. The web contains a funnel
at one end that serves as the spider’s retreat. The funnel is open
at both ends so the spider can readily escape. The spider hides at
the narrow end of the funnel; when it feels the vibration of an
insect crossing the web, it dashes out, bites the insect, then
carries it back to the funnel. Funnel Weavers and grass spiders are usually lighter in build than wolf spiders. Many
common funnel weaver and grass spiders are also characterised by
having very bristly legs. Most are brown, with grey, black, and tan
markings. Some have banded legs
and some have long spinnerets that extend out beneath the rear
of the abdomen. They will only bite if provoked, and are not considered dangerous.
Their bites are not
known to be very toxic to humans.
Spiders - Lyosidae, Genus Lycosa
The Wolf Spider got its name because it stalks
its prey like a wild dog. It is an open range hunting spider. The
female grows to 35mm and the male to 20mm. They are a small to
medium size spider. They can be grey or brown with marking on their
back which can be black, orange, grey or brown. The Wolf
Spider has three rows of eyes, two at the back, two in the centre
and four in the front. It is distinctive in the way it carries its
young on its back. The Wolf Spider is not an aggressive
spider. If the spider is handled, it can cause a painful bite which
may cause infection and skin lesions in some people. Females carry
their babies on their backs.
Click here for a photo.
The name Trapdoor Spider scientifically covers several families and many different species.
The Trapdoor spider family worldwide, include the Funnel-web, Mouse,
Whistling, and Curtain-web spiders; they are distinguished by the
stocky body, long leg-like palps, and two knee-like lobes to which
the fangs join (chelicerae) in front. However the spider called
Trapdoor in the USA is usually harmless to humans and the male is
often found around homes and swimming pools in its travels looking
for a mate.
Huntsman Spider - Heteropoda venatoria
Huntsman Spiders are those long-legged spiders we
often surprise crawling around our ceilings at night. They are part
of the "modern" spider species which breathe through trachea as well
as through "book-lungs". They also have chelicerae which close
side to side. The legs of a huntsman spider fan out sideways and the
joints bend forwards. This means these spiders can run sideways as
well as forwards - useful under bark and among stones.
Fishing Spiders - genus Dolomedes
Fishing Spiders are quite large and may
have a leg spread of 75 mm or more.
Fishing spiders are hairy,
large, and usually a mixture of black, brown, and grey. Although very difficult to
wolf spiders, nursery web and fishing spiders are usually
slimmer in build. The Dolomedes spiders
live near water; they walk on the surface of water and dive
underneath it to feed on aquatic insects and even small fish. Not
all fishing spiders live near water however.
Jumping Spider - Sitticus palustris
The Jumping Spider is a diurnal animal with
excellent eyesight, that pursues its prey and leaps upon it. It has
an all-round view of its surroundings because of its large, central,
front eyes. It is about the size of a 20c piece when fully grown,
with pin size legs. There are many different species but all jump
and turn their heads separately from their bodies to look at
objects. They live in houses and gardens and are most common in
Summer, Australia wide. It is a roving spider but hangs from web
lines at night. It rarely bites people and causes only mild local
Flower Spider - Thomisus spectabilis.
Another name for the Flower Spider is the Crab Spider
because it has white or yellow stout legs which are held like a
crab. The full size of the Flower Spider is between four and ten
millimetres. Flower Spiders are often white or yellow in colour,
some have green, brown or rosy tints on the abdomen. The females are
small and their legs are less than 7mm long. The males are even
smaller, but their legs are longer. They
normally have two large front eyes and have
very well developed eyesight. One species of crab spider is the
Tarantula is a hairy, long-legged, long-lived spider found mostly in warm
regions. Also sometimes known as Bird Spiders or Monkey Spiders, true
Tarantulas make up the family Theraphosidae; related forms, including
Funnel-web Spiders and Trap door Spiders, are also sometimes grouped
as Tarantulas. Many species are about 2.5 to 7.5 cm (1 to 3 in)
long, with a 13-cm (5-in) leg span, but some South American species
are larger. Tarantulas are often kept as pets and some in captivity
have been known to live for as long as 20 years. Tarantulas inject a paralysing venom into prey with
their large fangs. Their bite is unlikely to cause problems
other than pain at the site. Skin exposure to the urticating hairs
will cause itching and a rash.
Camel Spider -
Also known as Sun Spiders or Windscorpions, these strange looking
spiders were recently reported as being dangerous to the soldiers in
Iraq. The USA version is somewhat smaller than that specimen but is
quite often sent in to me for identifying. They live in
tropical or subtropical dry areas of the Americas, Asia, and Africa.
Worldwide, there are about 900 known species of Wind Scorpions, and
in North America there are 120. Most species of Wind Scorpion are
actually nocturnal, but they are often attracted to light. Apparently authentic cases of after effects resulting from a solfugid
bite have been recorded, but these symptoms were probably caused by
bacterial infection of the wound as poison glands have not been found to be associated with the chelicerae.
The parson spider is a nuisance in
homes and is generally non-toxic; although some people may experience
allergic reactions to the bites. The parson spider is about 1/2 inch
long and may vary in colour from brown to black. The front segment of
the body tends to be a chestnut colour, while the abdomen is greyish
with a distinctive white or pink pattern along its middle. The body
is covered with fine hairs, giving a velvety appearance. The parson
spider is usually found outdoors under rocks or in piles of brush or
firewood. This spider does not spin a web, but wanders on the ground
in search of prey.
Indoors, this spider wanders about at
night and conceals itself beneath objects or in clothing during the
day. Most bites from this spider occur at night or when it is
trapped in clothing. While the parson spider is not considered
venomous, bite symptoms are variable in severity. Some people may
experience localized allergic swelling and itching in addition to
initial pain. A few persons may experience excessive swelling,
nervousness, nausea, sweating and elevated temperatures from the
Green Lynx Spider
Lynx spiders get their name from the way that they sometimes pounce
on their prey in a catlike fashion. These spiders spend their time
hunting for insects in bushes and low plants. They are fast runners,
but can occasionally be seen lying in wait for prey beside flowers.
They build no web for prey capture, but they do release a silk
dragline as they hunt among leaves.
While the Green Lynx spider aggressively attacks its insect
prey, it very seldom bites humans.
DANGEROUS - MAY BITE AND COULD BE LIFE THREATENING
The spiders listed below have been known to cause
death or give bites that are classed as dangerous or life threatening. However,
there is an antivenin available for the Black Widow which is the
spider most likely to have caused deaths in the United States.
Click here for a map
showing the location of some of the dangerous spiders found in the
Web Spinning Spiders
Black Widow -
The black widow is one of the most commercially popular spiders and is a favorite Halloween costume for
here in the U.S. Widow spiders belong to the family of comb footed
spiders (Family Therididae). The female, about 1.3 cm (0.5 in) long, is glossy
black, densely clothed with microscopic hairs, and marked with a
characteristic red hourglass on the underside of the abdomen. The
male, which is rarely seen, is smaller than the female and has four
pairs of red marks along the
sides of the abdomen. The Black Widow is found
in the warmer regions in every state in the United
States except Alaska; it lives in a variety of natural and domestic
habitats. The venomous bite of the Black Widow Spider, causes muscle
spasms and breathing difficulty in humans and may be fatal. Black
Widows comprise about six species and inhabit most of the warmer
regions of the world to a latitude of about 45 degrees N. The female
black widow spider, though it is the most venomous spider in North
America, seldom causes death as it injects a very small amount of
poison when it bites. Reports indicate human mortality at well less
than 1% from black widow spider bites.
Brown Widow - Lactrodectus geometricus
The Brown Widow is of the same group as the Red-back
and the Black Widow but its toxin is about one-tenth the strength of
the Red-back toxin and does not cause the same severe reaction. Brown Widow Spiders usually curl up into
a ball, and drop to the ground as a primary defense. The Brown Widow
Spider is one of the species with the infamous "red hourglass"
marking on the underside of its abdomen. Only the females are
dangerous when it comes to any species of widow spider. It is an
introduced species in the United States and is found mainly in the
tropical states. According to Dr. G.B. Edwards, an arachnologist
with the Florida State Collection
of Arthropods in Gainesville, the brown widow venom is twice as
potent as black widow venom. However, they do not inject as much
venom as a black widow, are very timid, and do not defend their
web. The brown widow is also slightly smaller than the black widow.
- Loxosceles reclusa
The Brown Recluse spider (Loxosceles reclusa) is a
member of the "brown" spider family, Loxoscelidae. They are light in
colour and about 7mm long; their six eyes are arranged in two rows.
They are easily identified by the distinctive dark violin-shaped
design on its lighter upper abdomen. They are most common in the
western and southern United States. A few species of Brown Recluse
are harmful to man - including the brown recluse, which occurs in
the United States and Chile. When bitten, a blister arises around the area of the
bite. The local pain becomes intense with the wound sloughing tissue
(loxoscelism) often down to the bone. Healing takes place slowly and may take 6 to
8 weeks. If the bite of a brown recluse spider is suspected, collect
the spider and consult a physician immediately.
- Tegenaria agrestis
The Hobo Spider is a moderately large
spider which was originally native to western Europe and was
introduced into the north western United States (Port of Seattle)
sometime before the 1930's. This large brown spider has a
chevron pattern on the abdomen and is commonly seen running across
floors. The Hobo is especially active July to September, when males
search for females. Many bites previously attributed to the
Brown Recluse Spider are now thought to be caused by the Hobo Spider. It is now acknowledged as being the
leading cause of serious envenomation (tegenarism) in the northwestern United
States. However not all bites result in necrotic arachnidism in many cases the bites are "dry", and
no venom is injected .
Broad Faced Sac Spider
The broad face sac
spider, trachelas tranquillus, is often confused with
the woodlouse hunter, being similar in shape & colour. Its abdomen
is more sac shaped however
and is a light yellow/grey with
a darker marking on the
side. This is a hunting spider so it makes no web. However, it
builds a sac like tube to hid and rest in diurnally which is also
used to protect its eggs in autumn. This spider tends to forage on
other dead arachnids and insects which can cause its bite to be
particularly unpleasant due to infections.
Yellow Sac Spider -
Yellow Sac Spiders are relatively small (10 mm body
length), and are yellowish in color; they are difficult to
distinguish from one another. Bites generally produce instant,
intense stinging pain, not unlike that of the sting of a wasp or
hornet. This may be followed by localised redness, swelling and
itching; these manifestations may or may not evolve into a necrotic
lesion, but when that occurs healing is usually complete within
eight weeks. Side effects may include chills, fever, headache,
dizziness, nausea, anorexia, and sometimes shock.
Brazilian Wandering Spider -
The Brazilian Wandering Spider are very fast,
highly venomous, and extremely aggressive and is thought to be among
the most venomous spiders known. Recent studies however have found
that it only injects venom in about one-third of its bites and may
only inject a small amount in another third. Therefore the effects
of the bites from this spider can range from only a couple of pin
pricks to a full dose of its poison. In South America, these
spiders are often encountered in peoples' homes, hiding in shoes, hats, and
other clothes. It wanders the forest floor, which is how it got its
name. The Brazilian Wandering Spider also is called the Banana
Spider because there have been cases
where these spiders have appeared on banana boats heading
for the United States.
The mouse spider is known to cause severe illness,
especially to young children - similar to Red-Back Spider. Although
normally not aggressive, the male mouse spider will bite if
provoked, and should be considered dangerous to humans. It has large
hard fangs which can cause a deep painful bite. First aid and
medical attention (ambulance) should be sought as soon as possible.
It is a medium to large spider of up to 1 and 1/2 inches in body
length. The male Mouse Spider often has a bright red head and
elongated fangs. Mouse spiders are ground dwellers with
burrows of more than 3 feet deep. The male often wanders about
during the day on open ground, especially
after rain, in search of females.
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Guide in full colour of dangerous and other spiders that commonly
occur throughout Australia - features the Sydney funnel web, redback
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with notes to aid in identification.