may live as long as 20
to 25 years
George Seymour Outdoor California Writer
In mid-August one year I set a trapline for
coyotes in the foothills of the Sierra Nevada in Tuolumne County.
The line was extended into roughly a fifty‑mile loop, north
and south, and ran from two to three thousand feet in elevation.
I drove the abandoned railroad cuts and little‑used logging
roads each day tending my traps. I was aware of the increasing
number of large hairy spiders on and crossing the roadways every
day. I recognized them as tarantulas. By the end of the month, I
could see as many as six or eight a day, indicating a mass
migration. I knew this was the time of year when tarantulas were
commonly seen moving around in areas in which they occur, but what
I didn't know then was that the darker colored ones were probably
males searching for a mate. The females are seen less frequently
for in daylight they remain in their burrows or other hiding
Different species of this large spider occur
in many parts of the world, the largest being a tropical spider
found in South America. It may attain a span of seven inches and
is agile enough to catch small birds. The ones found in
North America occur in the southern and
southwestern states, including the dry and warmer parts of the
southern half of California. These are smaller and have a body
length of less than 2 inches and a leg span of from 3 to 4 inches.
There is a wide color variation, from a soft tan, through reddish
brown to dark brown.
They are all quite fearsome in appearance
with their long hairy legs and body covered with an almost mouse
like fur. Most people look at them with loathing; fearful that
they may jump up and bite. Actually, they can only jump forward a
few inches. For the most part they are harmless creatures. Even if
through carelessness a bite should occur, the venom when injected
into man causes only slight swelling, with some numbness and
itching which disappears in a short time. The chances of being
bitten are so few that one has little need to worry.
A tarantula is interesting to watch for it,
is a deliberate walker, picking its steps with the greatest race
and caution. In spite of its loitering gait it can cover
considerable distance in a day's time. People sometimes pick up
large slow-moving hairy spiders and let them
walk over their hands and arms. Some are even kept as pets. However,
you should be gentle and not restrain them forcibly, for they are
capable of inflicting a painful, although not dangerous wound
with their sharp fangs. The venom, which is injected through the
fangs, is as a rule harmful only to the small insects that it
captures for food.
The tarantula, like all its allies, does not
spin a web to capture its prey, but catches it by activity and
speed afoot. It feeds primarily on small insects: grasshoppers,
beetles, sow bugs and other small spiders. Upon seizing its prey,
it kills it with the venom. Through the wound made by the fangs it
injects a fluid from its mouth which digests the victims outside
the spider's body. This fluid reduces the prey to a consistency
where it may be sucked in by the spider with the aid of its strong
stomach muscles. It is then absorbed in the tarantula's stomach.
The tarantula prefers to live in dry,
well-drained soil. If the soil is suitable, the female digs a deep
burrow which she lines with silk webbing. This helps prevent sand
and dirt from trickling in. Otherwise, they hide in cracks in logs
and under any loose‑lying debris. In winter she covers the
entrance to her home with a plug of leaves and silk, and lies
dormant in her "den" until the return of spring. She
also uses the burrow as a safe retreat for moulting and guarding
her cocoon, and the newly hatched young in its depth.
Tarantulas are normally long‑lived
creatures. They do not reach sexual maturity for about 10 years.
During this time they undergo a series of moults, and until they
reach maturity you can't tell the male from the female. The mature
male is quite dark, nearly black, while the mature female is
brown. The degree of coloring varies with the species and
geographical location. Upon maturity the males abandon their
burrows and go forth to seek a mate.
Apparently, that was the fall movement of
tarantulas I witnessed in Tuolumne County.
After mating, the male lives only a short
time. It may die a natural death or be eaten by the female,
sometimes even before mating can occur.
When it comes time for egg laying, the female
spins a large sheet of webbing on which she deposits numerous
large pearly white eggs. They are covered by a second sheet of
webbing which is tightly bound at the edges. She guards this
flattened egg sac or cocoon‑carefully for six or seven weeks
until the eggs are hatched. The baby tarantulas stay in the
mother's burrow for a week or so before they go out and establish
dens of their own.
Some females may live as long as 20 or 25
years but long life in the wild is rare for they have many
enemies: lizards, snakes, spider-eating birds and the deadly
tarantula hawk. This large metallic blue, green and red wasp is
the spider's fiercest and most dreaded enemy. Once it has found
and paralyzed the spider with its poisonous sting, the wasp drags
its victim to a prepared burrow, deposits its eggs in the spider's
abdomen and seals its victim in. Upon hatching, the wasp larvae
feed on the tarantula's body.
Although the tarantula is frightening in
appearance, the chances of being bitten by it are rare, and,
because it has a rightful place in the outdoors, it should not be
wantonly killed or persecuted. If its presence is not desired, it
can be easily placed in a container and transported to some area
where it can continue, unmolested, to live its useful life.
This article is one of a series published by the
California Department of Fish and Game. Single-sheet reprints are
available to California residents from Department of Fish and Game
offices. Bulk quantities (minimum number: 25 copies) may be
purchased only from the Publications Section, Department of
General Services, P.O. Box 1015, North Highlands, CA 95660, for
$.04 each (includes state sales tax).