CPR First Aid

What are the Most Dangerous Spiders in the World?

What are the Most Dangerous Spiders in the World

Britannica, the oldest encyclopedia, identifies 9 of the most dangerous spiders in the world, including funnel-web and redback found in Australia. The other species are found in other countries and respective governments have a guideline on what to do in case of an encounter with them. For spider bites, first aid, antivenom, and hospital treatments are available and you will learn about these below.

What are the Most Dangerous Spiders in the World?

The following spiders have been responsible for human deaths, skin lesions, and allergic reactions.

Funnel-Web Spiders

The Australian Museum data shows that the male of the Sydney Funnel-web Spider (Atrax robustus) was responsible for 13 deaths before the introduction of antivenom in 1981. Its venom has a unique component called Robustoxin which affects the nervous system of humans. 

The Australian funnel-web spider and its close species are found in Eastern Australia. Appearance is a shiny carapace, closely grouped eyes, four spinnerets, and the lower lip has blunt spines. The males also have a spur on the middle segment of the second leg.

The Australian Museum data shows that the male of the Sydney Funnel-web Spider (Atrax robustus) was responsible for 13 deaths before the introduction of antivenom in 1981. Its venom has a unique component called Robustoxin which affects the nervous system of humans. 

Redback Spiders

The bites of the female redback spiders caused serious illness and death over the years. In Australia, more than 250 people receive antivenom each year. The venom acts on the nerves which then causes the release and subsequent depletion of neurotransmitters.

This deadly spider is found all over Australia and worldwide. As the name suggests, it has an orange-to-red longitudinal stripe on the upper abdomen. The size of the females is almost the same with a large pea and its legs are slender.

The bites of the female redback spiders caused serious illness and death over the years. In Australia, more than 250 people receive antivenom each year. The venom acts on the nerves which then causes the release and subsequent depletion of neurotransmitters.

Red Widow Spider

The bite of a red widow spider causes pain, cramping, and nausea which may make children and elderly people vulnerable. It is known to bite when protecting its eggs or when trapped inside clothes or footwear. 

It is found in Central and Southern Florida, USA, and experts believe their habitat is expanding.  Its legs are reddish and the abdomen is reddish-brown to black.

The bite of a red widow spider causes pain, cramping, and nausea which may make children and elderly people vulnerable. It is known to bite when protecting its eggs or when trapped inside clothes or footwear. 

Brown Widow Spider

The brown widow spider was linked to 2 deaths in Madagascar in 1990 and experts consider its venom to be powerful. However, they are not known to be aggressive and inject only a small amount of venom when they bite.

Its first specimen came from the USA and is thought to have evolved in Africa. Its appearance ranges from tan to almost black with the hourglass marking on the underside being orange.

The brown widow spider was linked to 2 deaths in Madagascar in 1990 and experts consider its venom to be powerful. However, they are not known to be aggressive and inject only a small amount of venom when they bite.

Black Widow Spider

More than 2,500 visits to poison control centres in the USA every year are because of the black widow spider. Its bite causes severe muscle pain, cramping, nausea, and mild paralysis of the diaphragm, leading to difficulty in breathing. The black widow spider bite may also be fatal to very small children and the elderly.

It is found in the USA, parts of Canada, Latin America, and the West Indies. The female has a reddish-to-yellow hourglass design on the underside of the spherical abdomen. On the other hand, the male often has pairs of red and white stripes on the sides of the abdomen.

More than 2,500 visits to poison control centres in the USA every year are because of the black widow spider. Its bite causes severe muscle pain, cramping, nausea, and mild paralysis of the diaphragm, leading to difficulty in breathing. The black widow spider bite may also be fatal to very small children and the elderly.

Wolf Spider

Wolf spiders bite in defense and they are venomous. The effect of its bite includes physical trauma at the bite site, itchiness, and possible panic due to the unsettling pain.

Wolf spiders are part of the family Lycosidae which is found throughout the world. Some species occur in North America, Europe, and the Arctic Circle. Most of them are dark brown, hairy, and have stout legs.

Wolf spiders bite in defense and they are venomous. The effect of its bite includes physical trauma at the bite site, itchiness, and possible panic due to the unsettling pain.

Yellow Sac Spider

The venom of the yellow sac spider is a cytotoxin (which destroys cells) and it may produce necrotizing lesions, redness, and swelling. It even makes it to 9News’s list of the most dangerous spiders in the world.

It’s found throughout the United States and Mexico. Its colour is light yellow or tan and its abdomen is slightly darker.

The venom of the yellow sac spider is a cytotoxin (which destroys cells) and it may produce necrotizing lesions, redness, and swelling. It even makes it to 9News’s list of the most dangerous spiders in the world.

Brazilian Wandering Spiders

Resources consider the Brazilian Wandering Spider as the deadliest spider in the world. Its venom is toxic to the nervous system which causes salivation, irregular heartbeat, and painful erections in men. 

The species are found in Brazil, Central and South America, Costa Rica, and Argentina. Most of their bodies are brown and gray with black bands.

Resources consider the Brazilian Wandering Spider as the deadliest spider in the world. Its venom is toxic to the nervous system which causes salivation, irregular heartbeat, and painful erections in men. 

Brown Recluse Spider

The Brown Recluse Spider is one of the scariest spiders in the United States as its venom destroys the blood vessel walls near the bite site. In some cases, it causes a large skin ulcer which takes several months to heal, or even lead to death.

Aside from living in the USA, this spider is also found in Mexico. Aside from being brown or blackish-gray, the front half of its body has a dark violin-shaped design.

The Brown Recluse Spider is one of the scariest spiders in the United States as its venom destroys the blood vessel walls near the bite site. In some cases, it causes a large skin ulcer which takes several months to heal, or even lead to death.

What to Do if You Encounter the Most Dangerous Spiders in the World?

According to Australian Geographic, it’s important to keep calm when you see a venomous spider. Call pest control, the Australian Reptile Park on 02 4340 1022, or the Poisons Information Hotline on 13 11 26.

What is the First Aid for the Bite of the Most Dangerous Spiders in the World?

Spider bite first aid may vary depending on the species of the spider. It’s important to wait for instructions from a pest control professional or the Poisons Centre. 

Is Anti-Venom Available for the Bite of the Most Dangerous Spiders in the World?

Anti-venom is available for many of the spider bites in Australia. It may be the same case in other countries. 

Conclusion

Some of the most dangerous spiders in the world include funnel-web, redback, red widow, brown widow, black widow, wolf spider, yellow sac, brazilian wandering, and brown recluse. Such species contain a venom that attacks the insides of the body which causes painful symptoms, skin ulcers, mild paralysis, and even death. Fortunately, first aid and antivenom are available for the spider bites. It’s also important to keep calm when you encounter them and seek advice from a pest control company or the Poisons Information Centre.

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