Sydney funnel web

Sydney funnel web
Atrax robustus

Humans and monkeys are affected by its venom, whereas animals such as toads, cats, and rabbits remain almost unaffected. 

The Sydney funnel web spider is a bulky, ugly-looking and relatively large (6-7 cm) spider much feared by the people in Australia. It can rear up on its hind legs when annoyed, aggressively exposing its massive fangs- they are strong enough to penetrate even a finger-nail. The spider attacks in a very specific manner: it grips its victim tightly and inflicts a series of  painful bites. It is only found in a radius of 160 km from Sydney and has caused several human deaths in that area since 1920. 

The venom of the smaller male is five times more toxic than the venom of the female. Unfortunately, males tend to appear in hot summer days after heavy rains and they often make their webs indoors. The main component of their venom is atraxotoxin which alone can cause all the symptoms. It is strange that humans and monkeys are affected by the toxins, while some animals like toads, cats and rabbits remain almost unaffected. 

Now that there is an effective antivenin created, the bites are rarely fatal. It is absolutely essential that an immediate first aid is given. Otherwise severe symptoms may develop that eventually lead to death. At first there is muscular twitching, increased salivation and lacrimation (secretion of tears), profuse sweating. Then tachycardia occurs, i.e. the heart starts beating very rapidly, and the blood pressure dangerously rises. The victim starts vomiting, he may lose consciousness and looks awful, with fixed dilated pupils. After two hours most of these symptoms start to subside and are replaced by hypotension (abnormally low blood pressure) which is due to severe cardiac failure.

First aid includes immediate transportation of the victim to a medical facility. The pressure-immobilization method must be applied as soon as possible and the bandage must not be removed prematurely. The medical personnel will treat the patient with antivenin and various other medicines that control the blood pressure, and muscle relaxants. Artificial ventilation and constant monitoring of the patient are needed.