Sydney, Australia, known for its opera house, infamous bridge, and pristine beaches is also home to the venomous Funnel-Web Spider. Even though this spider is located in a limited region, it is considered one of the deadliest arachnids because of its proclivity towards aggressive behavior.

Common and Scientific Names

Sydney Funnel-Web Spider (Atrax robustus)

Location

The Funnel-Web inhabits select urban and forested areas throughout New South Wales (NSW) and parts of Victoria (VIC). However, the majority of spider bites occur in a 160km (≈100 miles) circumference around Sydney.

Family

The Sydney Funnel-Web Spider is one of 36 species in the Hexathelidae family.

Unique Features

Their fangs are a dominant feature, visible to the naked eye. Venom is stored in the chelicerae, or mouth region. The fangs are able to easily penetrate through soft shoes and finger and toe nails. Its personality deviates from most other arachnids. Rather than scurrying to avoid a confrontation it takes on aggressive posturing and frequently attacks. The males have a spur used for mating that juts out of the middle of their second pair of legs, which is an important distinction in the event of a bite.

Feeding Habits

This arachnid is a carnivore. Their primary diet consists of insects and small vertebrates such as lizards and frogs. They are largely nocturnal hunters that rely heavily on silken trip-lines placed around its burrow to alert them to the presence of prey. Indiscriminate sheltered burrows rest throughout urban and forest settings. It is common to see these opaque white burrows in the ground, under rocks, or in tree stumps.

Natural Predators of the Predator

Larger lizards and birds of prey attack this spider quickly enough to avoid its venomous bite.

Size

Its body grows up to 5 cm (2 inches) long.

Behavior

When this spider perceives a threat, its natural response is to attack. It is quick to move and fast to strike. It is common for this spider to administer repeated venom bites. Females tend to live their lives out in their burrows unless displaced by natural or man-made events. Otherwise, they only leave the burrow only to retrieve food. Conversely, males travel vast distances through densely populated areas for the opportunity to mate. They tend to travel more at night in search of a female counterpart. However, during the day they seek out cool areas, which can attract them to modern dwellings. The highest frequency of bites occurs during the sensitive mating period in the summer and autumn months, December through May.

Effective Predatory Features

Male Sydney Funnel-Web Spiders carry venom that contains robustoxin. Interestingly, most mammals, aside from humans, do not face the consequence of death if bitten. However, in humans robustoxin interferes with the nervous system in as little as 15 minutes. The neurotoxin overloads the nervous system causing such symptoms as high blood pressure, nausea, vomiting, and glandular over activity, which leads to pulmonary edema whereby serum secretions fill the lungs and cause the victim to drown in their own fluids. While females have venom, its chemical makeup lacks robustoxin, rendering their bite innocuous.

Treatment

Anti-venom has been widely available since 1981. It is important to seek emergency care immediately, as people have become symptomatic in as little as 15 minutes. If emergency services are more than 15 minutes away, administer first aid. Apply a pressure immobilization bandage and help the person remain calm while seeking assistance. Since the introduction of anti-venom, there have been no reported deaths from this spider bite.



This is Deb Duxbury, for Animal Life, reminding you to please spay or neuter your pet.