Sydney funnel-web spider

Profile

The Sydney funnel-web spider is a venomous spider living in south-eastern Australia. It is considered one of the most dangerous spiders in the world due to both its strong venom and aggressive nature. The head is mostly bald, but the abdomen and legs are covered in small hairs. Males have a skinnier body and legs than the females do. They also have small spurs on their second legs for holding on to the female during mating.

These spiders are some of the most aggressive spiders in the world. If they feel threatened, they will rear back in the position shown above. They will raise their front legs high, making them appear larger, and they will bare their fangs, preparing to strike. It the threat doesn’t leave, the spider will strike hard. Their bites have been known to puncture boot rubber and even fingernails!

Size

Male Sydney funnel-web spiders are smaller than the females, as it is with most spiders. The males are about an inch (2.5 cm) long, and the females can grow up to 1.4 inches (3.5 cm). Although most of these spiders are somewhat close to these measurements, some may be as small as 0.6 inches (1.5 cm) long. All of these measurements are just the body length and do not include the legs.

Diet and hunting

As with most spiders, Sydney funnel-web spiders eat mostly insects. They will also eat snails, millipedes, and sometimes even small frogs and lizards! These spiders do not hunt their prey. Instead, they build a funnel-shaped web, from which they get their name.

This spider’s webs are actually more like burrows. The web would be best describes as a tunnel of silk going under rocks, logs, or other debris. The spider will have two entrances to the tunnel, both with wide mouths narrowing into the tunnel, like a funnel. These tunnels can be rather large, up to two feet (6o cm) long!

When an insect wanders to the entrance of the tunnel, it will get stuck on the silk. The spider will feel the vibrations in the silk made by the struggling insect and go out to attack it. It will bite its prey several times before taking it in to eat.

Venom and bites

These spiders have venom that is similar to that of the blue-ringed octopus, and it’s not because both animals have eight legs/tentacles. Both venoms act by keeping the brain from sending signals to the muscles. Bite victims will sometimes lose control of their limbs and have uncontrollable muscle spasms.

Luckily, only about 1/6 of the bites from this spider are serious, as the spiders don’t always inject a large amount of venom. There have only been 15 reported deaths from these spiders ever, and none since 1981, which was when an antivenom was developed. All reported deaths were from the male spiders, which, unlike with most spiders, are up to 6 times as venomous as the females!

The antivenom is somewhat hard to make as it requires milking the spiders for their venom. Just one dose of the antivenom requires about 70 milkings of the spider!

Habitat and range

Sydney funnel-web spiders only live in the south-east corner of Australia near the coast. They are named after Sydney, Australia, the city their range is centered around. There are other species of funnel-web spiders that inhabit much of the rest of Australia, but these prefer to stay near the ocean where the climate isn’t quite so dry. Forests and gardens are great places for these spiders to live as they provide protection and a large amount of prey.

Although water is not scarce in their habitat, Sydney funnel-web spiders are attracted to water. This would be really bad for most spiders, but this species can trap air bubbles in their hairs, letting them survive immersion in water for over 24 hours! Although they don’t live in houses, these spiders may be found in houses occasionally, normally after a heavy rain from which they were seeking shelter.

Reproduction

Female Sydney funnel-web spiders spend almost their entire lives in their burrows. After heavy rains, the males will wander around in search of a female. When he finds a burrow, he will try to attract the female out without becoming her next meal.

After mating, the female will create an egg sack containing around 100 eggs in her burrow. After hatching, the spiderlings are on their own and leave the burrow almost immediately.

It takes about 4 years until the males are ready to mate and one year longer for the females. The males will die a few months after mating for the first time. The females will live a few more years.

Sources:

Photo credits:

  • Sydney funnel-web spider – Wikimedia user: Tirin

 

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