Spiders are arthropods that have eight legs and chelicerae with fangs that inject venom.
They are 7th in the world when it comes to diversity among their populations.
There are about 45,000 known species of spiders.
They can be found on every continent in the world except Antarctica.
Spiders can thrive and live in almost any place: on the edges of the ocean, on plants, under rocks, in trees, in caves and even over the water. The only places that spiders cannot inhabit are the oceans, the highest mountains and the polar regions.
Most spiders live anywhere from 1 to 3 years; but female tarantulas are know to live up to 30 years.
Patu digua is by some accounts considered to be the smallest spider in the world. Males reach a body size of about 0.37 millimeter (0.014 inch), roughly the size of the head of a pin.
The largest spider in the world is the Goliath Bird-Eating tarantula (Theraphosa blondi), with a leg-span of up to 28 cm (11 in), a body length of up to 11.9 cm (4.7 in) and can weigh up to 175 g (6.2 oz).
Many spiders have unusual body shapes and colors. Bizarre bodies can be helpful to spiders in various ways – to deceive and ambush prey, to capture particular sorts of prey, to avoid being eaten and to attract mates.
Spiders are not insects. They have 8 legs while insects have 6; they don’t have antennae while insects do; and spiders have “simple” eyes instead of the “compound” eyes that give many insects
much better vision.
Spiders have two body segments, the abdomen and the cephalothorax. The first, or front part, is the cephalothorax, which is formed by the fusing of the head and thorax. The cephalothorax contains the eyes, mouth and legs.
The mouth has several parts. The spider’s jaws, called the chelicerae, are tipped with fangs. Behind the jaws are the labium and labrum, which work together to direct food into the spider’s mouth.
The first appendages behind the mouth are called pedipalps, used to sense objects the spider encounters.
Spiders have primarily four pairs of eyes on the top-front area of the cephalothorax, arranged in patterns that vary from one family to another. Spiders don’t have very good vision, they are nearsighted.
A spider has no bones. Rather, it has an exoskeleton, which is like a hard suit of armor that protects its body. Because an exoskeleton does not grow, a spider molts. Molting occurs frequently when a spider is young, and some spiders may continue to molt throughout their life.
A spider’s abdomen is where most of its important internal organs are located, such as the reproductive system, lungs and digestive tract.
The abdomen has no appendages except those that have been modified to form one to four (usually three) pairs of short, movable spinnerets, which emit silk. Each spinneret has many spigots, each of which is connected to one silk gland. There are at least six types of silk gland, each producing a different type of silk.
Spider webs vary widely in size, shape and the amount of sticky thread used.
Webs are a great way to catch a meal, but not all species use webs for that purpose; some use webs like a clothesline to hang their egg sacs or to line their burrow homes. The shape and size of webs also varies among species: in fact, spiders are grouped taxonomically according to the type of web they make. Groups include tangle-web spiders, orb-web spiders, funnel-web spiders and nursery-web spiders.
Spider silk is the strongest known natural fiber, with a breaking strength greater than bone or tendon and half the strength of steel!
Spiders use a wide range of strategies to capture prey: trapping it in sticky webs, lassoing it with sticky bolas, mimicking the prey to avoid detection, or running it down.
All spiders are carnivorous, which means they eat a variety of insects and other spiders. Large spiders are able to eat small vertebrates like mice, small birds and lizards.
Although nutritional requirements vary by species, spiders can usually go for extended periods of time without eating. In fact, some species may go for several months without a meal, while others may eat every day.
Even though they are predators they can only take in liquid food. The venom allows them to change their prey into a liquid substance.
Only a few species are dangerous to humans, and even they won’t bite unless they feel threatened.
Most spiders live alone, meeting other spiders only to mate. A few species of spiders are social and live in groups.
Female spiders produce egg sacs with up to 2,500 eggs inside, depending on the species. Baby spiders are called spiderlings, but most are eaten before they have a chance to mature. The mother spider usually doesn’t stick around to protect her eggs or her young, so the spiderlings are on their own as soon as they hatch.
Many female black widow spiders eat their males after mating.
Spider blood is pale blue, not red.
Spiders need all eight of their legs. Luckily, if a leg is lost, the spider can regenerate a new one through several molts.
When a spider travels, it always has four legs touching the ground and four legs off the ground at any given moment.
Spiders detect smell with scent sensitive hairs located on their legs.
Jumping Spiders are able to jump up to 50 times their own length. This is possible due to increasing the amount of blood pressure found in the back limbs.
Spiders are very important to the health of the ecosystem because they eat insects and other arthropods and keep their numbers in check.
It is estimated that 25 million tons of spiders kill 400–800 million tons of prey per year.
Spiders can eat their own weight in one meal.
The Bagheera kiplingi is the world’s only (mostly) vegetarian spider.
Spiders can survive for hours underwater by entering a self-induced coma.
Spiders sometimes sail through the air on a line of silk, which is known as “ballooning.”
The strongest silk ever found is made by the Darwin’s bark spider in Madagascar, which spins silk that is reportedly 10 times tougher than Kevlar, thanks to its elasticity, or ability to stretch without breaking.
Defining the term “most venomous” as the most toxic to humans (as some venomous spider species show varying degrees of toxicity to different animal species envenomed by them), the world’s most venomous spider is the male Sydney funnel-web spider Atrax robustus – according to Guinness World Records.
With speeds clocked at 0.53 m/s or 1.73 ft/s (1.9 km/h or 1.18 mph), the giant house spider held the Guinness Book of World Records for top spider speed until 1987 when it was displaced by sun spiders (solifugids) although the latter are not true spiders as they belong to a different order.
The word “spider” comes from the Old English word spithra and is related to the German spinne, both ofwhich mean “spinner.” The word “spinster” is also related and means “one who spins thread.”
Spiders and their relatives are called arachnids. Arachnids include spiders, scorpions, pseudoscorpions, amblypygids (tailless-whipscorpions), schizomids (micro-whipscorpiones), palpigrades, harvestmen, ticks and mites.
There have been some fossil remains of Spiders found. It is believed that they are at least 300 million years old but it could be as much as 400 million years ago.
Arachnophobia is the fear of Spiders. It is one of the most common fears in the world. It affects approximately 10% of men and 50% of women.