Spiders can be found in garages, basements, attics, cabinets, sheds, gardens, woodpiles, in the garbage, under tree bark, and inside of homes. Spiders have four pairs of legs and fangs at the ends of their mouths to bite the prey and inject venom.
All spiders are predatory eight-legged creatures that have organs to spin silk at the back ends of their bodies.
Spiders all have the ability to bite with venom-injecting fangs to kill prey and nearly all of them are poisonous.
There are about 40,000 types of spiders in the world, living on every continent except Antarctica.
They're not newbies: fossilized spiders have been found in Carboniferous rocks dating back 318million years.
Spiders have two body segments, the abdomen and the cephalothorax.
The spider's jaws, called the chelicerae, are tipped with fangs, according to entomologists at the University of Kentucky.
These appendages are used to hold prey while the spider injects venom.
Behind the jaws are the labium and labrum, which work together to direct food into the spider's mouth.
Between the chelicerae and the first pair of legs are the pedipalps, which look like tiny legs but are actually similar to antennae, and are used to sense objects the spider encounters
Most spiders have six or eight eyes, according to the University of Kentucky.
Some spiders can only see the difference between light and shadow.
A spider's abdomen is where most of its important internal organs are located, such as the reproductive system, lungs, and digestive tract.
Also on the abdomen are the spinnerets, through which a spider produces its silken web.
Some spiders use their webs to trap prey; others line their burrows with it.
Spiders are grouped according to the type of web they make
Groups include tangle-web spiders, orb-web spiders, funnel-web spiders, and nursery-web spiders.
According to the Australian Museum, spiders capture prey using a variety of methods.
Spider guts are too narrow to take solids, so they liquidize their food by flooding it with digestive enzymes and grinding it up with short appendages.
Even though all spiders can bite, most of them do no more harm to a human than a bee sting or a mosquito bite.
According to Spider Physiology and Behaviour, Volume 41, there were only about 100 deaths from spider bites during the 20th century.
Spider venoms work on one of two fundamental principles: they either attack the nervous system with neurotoxic venom or attack tissues around the bite with necrotic venom.
Researchers are investigating novel uses for spider venom, from an eco-friendly alternative to pesticides to treatments for Alzheimer's disease, cardiac arrhythmia, and strokes.
Spider silk has lots of engineering uses, from body armor to optical communications.
Arachnophobia, or fear of spiders, is one of the most common phobias.
According to Mentally Healthy, evolutionary biologists surmise that a modern fear of spiders may be an exaggerated form of an instinctive response that helped early humans to survive.
Other scholars think that fear of spiders began in the Middle Ages, when spiders became a cultural scapegoat for inexplicable epidemics of the time, like the plague.
Spiders can be divided into two suborders: Mesotelae and Opisthothelae, which contains the infraorders Mygalomorphaeand Araneomorphae.
The members of this family are quite distinctive from all other spiders. that the Mesothelae suborder is so named because its members have their spinnerets located on the middle of the abdomen, on their underside.
According to the Australian Museum, these are"Primitive spiders"; "Modern" spiders have spinnerets toward the back of their abdomens.
Though scientists previously thought they lacked venom glands, new research has shown that they do have them.
Opisthothelae: These spiders have spinnerets at the posterior of their abdomens
"Mygalomorph spiders also have two pairs of book lungs while araneomorph spiders have one pair of book lungs or no book lungs at all."
Mygalomorphae: According to Arachne.org, these spiders are generally heavily built and hairy, like tarantulas.
Although most spiders live for at most two years, many spiders can live up to 25years in captivity.
This type of spider includes the huge goliath bird eater, which can grow up to 1 foot in body length, according to the Conservation Institute.
Araneomorphae: These are the most common of spiders, making up more than 90 percent of all the species, according to Biology of Spiders.
Some of the most interesting species include the only known vegetarian spider, the Bagheerakiplingi, as well as the most venomous spider, the Brazilian wandering spider.
Scientists have found that the spider needs to inject only 6 micrograms of its venom to kill a 20-gram mouse, and a full venom load is more than 10 times that.
Spider bites are relatively rare. However, spiders may bite when they feel threatened, such as when they are wedged between a part of the human body and an object. Most spider bites are harmless, as spider venom is not thought to be toxic to humans. Generally, a spider will not bite multiple members of the same household. Some spider bites are painful, while other bites are painless. A spider bite will usually resolve on its own within 7-10 days. The skin site should be watched, as spider bites can get infected.
COMMON SYMPTOMS OF A SPIDER BITE:
• Raised, red bump(s) • Mild, moderate, or severe pain
• Pain a few hours after the bite
• Vision changes
• Kidney failure
• Skin tissue death
RARE SYMPTOMS OF A SPIDER BITE:
• Flu-like symptoms, including fevers, sweating, nausea, and vomiting
• Increases in blood pressure
• Life-threatening allergic reaction
• Abnormal heart rate or rhythm
• Muscle aches
• Excessive saliva
• Muscle contractions
• Chest pain
• Belly pain
• Death is possible
HOME TREATMENT OF A SPIDER BITE:
• Wash the skin with soap and water.
• Apply an ice pack to the bite for 15 minutes at a time. Wrap the ice pack in a towel to protect the skin.
• Keep the bitten area raised above the level of the heart, if possible.
• Take over-the-counter anti-inflammatory medication, such as Ibuprofen.
• Collect the spider if possible or try to remember what the spider looked like so that the type of spider can be determined.
WHEN TO SEE A DOCTOR FOR A SPIDER BITE:
• Tetanus shot, particularly if last tetanus shot was more than 5 years ago
• Antibiotics if there are signs of infection, including but not limited to: fevers, redness, swelling, pain, and pus
• Prescription medications to treat pain, inflammation, nausea, vomiting, muscle spasms, and muscle contractions. In rare cases, epinephrine may be given for a life-threatening allergic reaction.
• Anti-venom to treat severe symptoms (such as muscle pain and spasms). Need for anti-venom is based on symptoms
• Hospitalization for pain control if the pain is severe and surgery to remove any dead skin tissue
This video and article is for information only and should not be used for the diagnosis or treatment of medical conditions. We used all reasonable care in compiling the information but make no warranty as to its accuracy. Always consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions.