List of the Top 5 Most Venomous Spiders in the World


1) Sydney Funnel-web Spider (Atrax robustus)

  • Location: Eastern Australia, especially around Sydney.
  • Venom: Contains potent neurotoxins that can cause severe symptoms such as muscle spasms, breathing difficulties, and cardiac arrest. The toxicity of the venom varies, with male spiders being significantly more toxic than females.
  • Fatalities: Prior to the development of an effective antivenom in the 1980s, 13 deaths were reported. Since then, no deaths have been reported due to prompt medical intervention.
  • Behavior: Extremely aggressive and will bite multiple times when threatened. They inhabit moist environments such as forests and urban gardens.

2) Brazilian wandering spider (Phoneutria spp.)

Location: Central and South America, commonly found in banana plantations.

Venom: Neurotoxic, affects the nervous system and causes symptoms such as salivation, irregular heartbeat and severe pain.

Death: Bites from this spider can be serious, especially for children, but only a small percentage require anti-venom treatment. This spider is known for its aggressiveness.

Behavior: These spiders usually hide in dark, damp places and are known for their bites that inflict pain (but don’t inject all of their venom).

Black widow spider (Latrodectus mactans)

Location: Found throughout the world, especially in North America.

Venom: Contains neurotoxins that can cause severe pain, muscle cramps, nausea, and mild diaphragm paralysis, making breathing difficult.

Death: Deaths are rare due to effective medical treatment; bites are more dangerous for children and the elderly.

Behavior: They are generally not aggressive, prefer hiding in dark corners, and are known for their distinctive red hourglass markings.

Brown Recluse Spider (Loxosceles reclusa)

Location: Central and Southern United States.

Venom: Cytotoxic, causes necrosis (tissue death) at the bite site. Symptoms include severe pain and extensive skin ulceration.

Death: Rare, but complications from the bite may lead to serious health problems such as gangrene.

Behavior: They are not usually aggressive and will only bite if provoked or trapped. They prefer dark, secluded areas such as attics and basements.

Redback spider (Latrodectus hasselti)

Setting: Australia, particularly urban areas.

Venom: Similar to black widow venom, contains neurotoxins that can cause severe pain, muscle weakness, nausea, and respiratory failure.

Fatalities: Due to the availability of antivenom, fatalities are rare; only one death has been reported since the antivenom was developed.

Behavior: Will usually bite humans if disturbed; this spider can be identified by the distinctive red stripe on its back.

Six-eyed sand spider (Sicarius spp.)

Location: Southern Africa, mainly in deserts and arid areas.

Venom: Extremely toxic, believed to cause bleeding, blood clotting, and tissue damage. Due to its elusive nature, no human bites have been confirmed.

Fatalities: Rarely encountered by humans, so documented bite cases are rare.

Behavior: Secretive in behavior, spending most of the time buried in the sand waiting for prey.

  1. Chilean Recluse Spider (Loxosceles laeta)

Location: South America, especially Chile.

Venom: Contains cytotoxins and can cause severe necrotic lesions and systemic symptoms.

Death: Bites may cause severe tissue damage, but death is uncommon.

Behavior: Similar to the brown recluse spider, it is not aggressive and will usually bite only when provoked.

While these spiders are dangerous, they do not usually cause death due to advances in medical treatment and antivenom. Vigilance and prompt medical attention are essential to effectively managing spider bites.

Chilean Recluse Spider (Loxosceles laeta)

Location: Native to South America, particularly Chile, but reported in parts of the United States.

Physical characteristics: Small to medium-sized spiders, usually 1.5 to 2.5 cm in length. They have distinctive violin-shaped markings on their cephalothorax.

Venom: Contains cytotoxins that can cause severe necrosis at the bite site. Symptoms range from mild irritation to severe skin damage and systemic reactions.

Effects on humans: Bites can cause severe tissue necrosis and, in rare cases, death. The CDC reports that about 3-4% of bites result in serious complications. Wounds may take months to heal and often leave scars.

Behavior: Generally reclusive, preferring dark, undisturbed areas such as attics and basements. They are not aggressive and will usually bite only if provoked.

Six-eyed sand spider (Sicarius spp.)

Location: Mainly found in deserts and arid areas of southern Africa, including Namibia.

Physical characteristics: Medium-sized, 8 to 15 mm long. Has six eyes in three pairs, and a flat body that helps with camouflage.

Venom: Extremely toxic, believed to cause bleeding, blood clotting, and severe tissue damage. Its venom is considered more damaging than that of the recluse spider.

Effects on humans: Confirmed human bites are rare, but the venom is thought to cause severe necrotic lesions. No antivenom is available, and bites may cause serious health complications.

Behavior: They primarily ambush predators, burying themselves in the sand and waiting for prey to approach. They are elusive and rarely encountered by humans.

Katipo spider (Latrodectus katipo)

Location: Native to New Zealand, mainly found in coastal areas and coastal forests.

Appearance: Small in size, about 1.5 cm long, with a distinct red stripe on the back, often confused with the more well-known black widow spider.

Venom: Contains neurotoxins similar to those of the black widow spider. The venom can cause severe pain and systemic symptoms.

Effects on humans: The bite causes severe pain, muscle spasms and systemic reactions, but deaths are rare due to effective medical treatment.

Behavior: Katipo spiders are generally shy and solitary, preferring to hide in vegetation and are not aggressive. Bites usually occur when the spider is accidentally disturbed.

How does the venom of the six-eyed sand spider compare to other deadly spiders?

The venom of the six-eyed sand spider (Sicarius spp.) is considered so potent that it is often compared to the venom of other deadly spiders due to the serious health problems it can cause. Here’s how it compares to some of the world’s most venomous spiders:

Venom Characteristics

Six-eyed sand spider (Sicarius spp.)

Venom composition: The venom contains multiple toxins that can cause bleeding, blood clotting, and severe tissue damage. It is believed to be cytotoxic and can cause necrosis similar to that of a recluse spider bite.

Effects on humans: While there have been no confirmed cases of humans being bitten by venomous snakes, the venom is thought to be capable of causing severe injuries, including large open sores and possibly death. Due to the lack of documented cases, it is difficult to determine the exact effects of the venom on humans.

Antivenin: There is currently no antivenom available for six-eyed sand spider bites, which increases the risk of envenomation.

Comparison to other deadly spiders

Sydney Funnel-web Spider (Atrax robustus)

Venom: Contains potent neurotoxins that can cause severe pain, muscle spasms, and respiratory failure.

Fatalities: Historically there have been fatalities, but none since the development of antivenom in the 1980s.

Antivenin: Available and effective.

Brazilian wandering spider (Phoneutria spp.)

Venom: Neuroactive venom that can cause severe pain, sweating, and cardiac arrhythmia.

Deaths: A few deaths have been reported, especially in children, but antivenom is effective.

Antivenin: Available and can significantly reduce mortality.

Black widow spider (Latrodectus mactans)

Venom: Contains a potent neurotoxin that causes severe muscle pain and cramps.

Death: Rare, with effective treatment.

Antivenom: Available, but most bites require symptomatic treatment.

Brown Recluse Spider (Loxosceles reclusa)

Venom: Cytotoxic, causes necrosis and severe skin damage.

Death: Very rare, but bites can cause severe tissue damage.

Antivenin: There is no specific antivenom, but treatment focuses on wound care.

Summary

While the venom of the six-eyed sand spider is thought to be extremely potent and deadly, knowledge of its venom’s effects is limited by the fact that humans rarely come into contact with this spider. In contrast, other spiders, such as the Sydney funnel-web spider and the Brazilian wandering spider, have well-documented venom effects and available antivenom, leading to greater knowledge of their medical significance. The six-eyed sand spider remains of concern due to its potential venom, but due to the lack of human bite cases, little is known about its true danger compared to other deadly spiders.