Most Venomous Spider in the World

The Brazilian wandering spider possesses the most active neurotoxic venom of any living spider

The most venomous spider is the Brazilian wandering spider, which belongs to the genus Phoneutria. The Brazilian huntsman Phoneutria fera possesses the most active neurotoxic venom of any living spider. Its venom is so lethal such that it only takes 0.006 milligram or 0.00000021 ounce of poison to kill a mouse. This dark-colored spider has an average body and leg spread of 17 centimeters or 6.75 inches.

Known By Other Names

This type of spider is also known as the armed spider or the banana spider and is considered aggressive. It can be found in tropical South American countries such as Argentina, Colombia, Venezuela, Ecuador, Bolivia, Paraguay, Brazil and Ecuador while a lone species exist in Central America and many of which live in Costa Rica.

The Brazilian wandering spider is vital in the medical field because of its potential medical significance to humans.

An effective antivenom is available for treating person bitten by the Brazilian wandering spider that is why fatalities are few. Mostly kids 7 years old and below are the reported fatalities.


This poisonous spider Phoneutria is identified by the dark liner stripe or stripes on the front palps as well as with the single thin black line that extends anterior-posterior along the dorsal carapace. Other distinct features of the Brazilian wandering spider or the Brazilian huntsman is a clear ventral marking at the underside of the legs with contrasting mid segments and and lighter joints. A pattern on the underside of the abdomen has multiple rows of block dots or a generally reddish shade.


The Brazilian wandering spider usually moves aggressively along the jungle floor at night time and is not used to making or maintaining a web. These spiders hide in termite mounds during the day and sometimes dwell under fallen logs and rocks and also in banana plants at the same time of the day. Mating of the Phoneutria species happen in the dry season between April to June.

Bite Effects

The Brazilian wandering spider bite is deadly! Its venom contains a potent neurotoxin known as PhTx3. The deadly venom causes loss of muscle control as well as breathing problems which lead to paralysis and asphyxiation.

The person bitten by Brazilian wandering spider also experiences intense pain and inflammation due to the excitatory effect of the venom. Aside from the intense pain, the venom also causes priapism in humans while erections caused by the bite are uncomfortable and can last for many hours but can lead to impotency. The venom is already being studied as a cure for erectile dysfunction.

Leave a Reply