Meet the Big Boy Spider and Its Deadly Funnel Web Relatives

There are big spiders, and then there’s the Newcastle ‘Big Boy.’ First described in the early 2000s, this spider is the largest type of funnel-web spider found in Australia. Confusion over the Big Boy and related funnel-web spiders led scientists to classify them all under a single category. However, a new study published in the BMC Ecology and Evolution journal illustrated that the funnel-web spider is not a monolith. Instead, they are a complex of three related but distinct species. Not only does this study raise questions about species concepts, but it also suggests practical implications regarding antivenom production for this highly venomous spider. Given this new development, let’s learn more about the ‘Big Boy’ spider and its relatives.

What Are Funnel-Web Spiders?

The Sydney funnel-web spider (Atrax robustus) was first described in 1877 from a single specimen found in “New Holland,” the first name for mainland Australia. They are black, with a glossy sheen, and grow up to 1.5 inches long. They are also some of the most venomous spiders to humans.

Sydney funnel-web spiders get their name for two main reasons: they create long, silk-lined burrows and are commonly found in suburban areas around Sydney. When summer arrives, male funnel-web spiders leave their burrows looking for mates. This often brings them into houses where they encounter humans. While not inherently aggressive, Sydney funnel-web spiders will attack when cornered. If they bite, they inject venom containing a toxin that attacks the human nervous system. Without immediate medical attention, a person can die from their bite within hours, and in rare cases, severe symptoms can develop in as little as 15 minutes, especially in children.

Since the first description of the Sydney funnel-web spider, scientists have discovered that these formidable arachnids are more diverse than previously thought. The Sydney variety is only one type of funnel-web spider.

Confusion and Clarification

A study published in January in the BMC Ecology and Evolution journal questioned the broad classification of Sydney funnel-web spiders. Using several tools, the study’s authors made a fascinating discovery. The Sydney funnel-web spider is actually a complex of three species. The Sydney funnel-web spider was first described about 150 years ago as Atrax robustus. Around 50 years later, another species was described as Atrax montanus. Eventually, this classification was discarded as inaccurate. However, the authors of the study discovered that Atrax montanus does exist. They also described a third, and the largest, related funnel-web spider species: Atrax christenseni. They are named after Kane Christensen, the former head of spiders at the Australian Reptile Park. He first described this variant in the early 2000s and nicknamed them “big boys” because of their impressive size.

For years, people—including scientists—classified all funnel-web spiders as the Sydney variety. However, the reality is more nuanced. By collecting spiders from the Sydney suburbs and comparing them to other specimens, the study’s authors discovered a species complex. The true Sydney funnel-web spider lives in the Sydney metropolitan area. The previously discarded species, Atrax montanus,  is real and is found farther south and west, in more rainforest-like environments. The species observed by Kane Christensen, Atrax christenseni, lives around 105 miles north of Sydney, in the area surrounding the city of Newcastle. Atrax christenseni is currently recognized as the largest known funnel-web spider species.

Biochemical and Antivenom Implications

This discovery of a species complex has profound implications because Australian funnel-web spiders are highly venomous and can deliver venom that is potentially fatal to humans. Researchers developed the first funnel-web spider antivenom in 1981, and no human deaths from funnel-web spider bites have been recorded in Australia since its introduction. However, current research indicates that the existing funnel-web spider antivenom is effective against all three species, including the newly classified ones.

Nevertheless, confusion about the three species may mean that current antivenoms are not as effective as they could be. This new study suggests that differences among funnel-web spider species also mean differences in venom structure. Considering that each species has varying amounts of specific compounds in its venom, new, tailored antivenoms can be developed. Beyond the biochemical implications, this reclassification and expansion of funnel-web spider taxonomy suggest that there may be subtle but distinct variations in many similar species around the world. When it comes to venomous species, understanding their subtle differences could help save more lives.