New Zealand and Australia share many similarities as neighboring countries, but when it comes to spiders, there are some key differences. If you’re wondering whether New Zealand has to deal with spiders as sizable and scary as some of Australia’s arachnids, read on.
If you’re short on time, here’s the quick answer: While New Zealand has native and introduced spider species, it does not have nearly the same level of large, venomous spiders found in Australia.
In this nearly 3000 word guide, we will compare the native and introduced spiders found in New Zealand to those infamous ones found in Australia. We’ll look at spider size, venom levels, habitat, and more to help you understand if New Zealand truly faces a spider situation comparable to that across the Tasman Sea.
Native New Zealand Spiders
Appearance and Size
New Zealand has around 100 native spider species, most of which are relatively small and harmless to humans. The largest native spider is the cave spider (Spelungula cavernicola), which has a legspan up to 12cm. Most other native spiders are much smaller, with bodies only 5-10mm long.
They have eight legs and two main body segments. Their colors vary from drab browns and greys to brighter reds, greens and yellows. Some species exhibit striking patterns on their abdomens. Compared to Australian spiders, New Zealand’s native spiders are generally smaller and less hairy.
Venom and Bites
Only a handful of New Zealand’s native spiders have bites that could affect humans. The venom of the katipo (Latrodectus katipo) and redback (L. hasselti) can cause severe pain, sweating and nausea, but are very rarely life-threatening.
Most other native species have weak venom unsuitable for capturing large prey like possums or birds. If they do bite humans, the effects are usually no worse than a bee sting. Various introduced spiders in New Zealand do pose more significant bite risks, such as the white-tailed spider and black widow spider.
But in general, New Zealand’s native spiders should not cause too much concern if left alone.
Habitat and Behavior
New Zealand spiders are found throughout the country in forests, fields, gardens, beaches and caves. Many species construct silk retreats under rocks, logs or flaking tree bark. Web-building species spin messy, tangled webs rather than the neat, circular webs of orb spiders.
Native spiders help control insects and are an important part of the country’s ecosystems. They are generally shy and nocturnal. The cave spider is New Zealand’s only endemic spider and is found only on the southern South Island. Most other native species also occur in Australia.
Introduced Spiders in New Zealand
Appearance and Origins
New Zealand has several species of introduced spiders that are not native to the islands. Many of these spiders hitched rides on ships and cargo from Australia, Europe, Asia and other parts of the world over the past few centuries.
Some of the most common introduced spider species in New Zealand include:
- The black house spider – This medium-sized spider has a round, black body with light grey markings. It likely originated in Europe or North Africa before spreading to Australia and New Zealand.
- The redback spider – With a notorious venomous bite, this small black spider with a prominent red stripe on its abdomen is closely related to the black widow spider. It is native to Australia but now found in New Zealand as well.
- The white-tailed spider – A larger spider marked by a cylindrical, brown body and white spot at the end of the abdomen. It is native to southern and eastern Australia and was accidentally introduced to New Zealand last century.
Threats to Native Wildlife
Many of New Zealand’s native invertebrates did not evolve defenses against predatory spiders. Introduced spiders can thus be a significant threat, especially to rare endemic insects, snails and other bugs. For example, the redback spider is known to eat native beetles, moths, flies and bees.
White-tailed spiders also prey on a wide variety of small invertebrates. This added predation pressure from invasive spiders may harm vulnerable native populations already stressed by habitat loss and other factors.
Danger to Humans
While New Zealand has no dangerously venomous native spiders, some introduced species do pose a potential health risk. The Australian redback spider has a neurotoxic venom that can cause severe pain, sweating and nausea if bitten. Antivenom is available for treatment.
The white-tailed spider’s bite can cause temporary skin irritation and pain. However, there is limited evidence that it causes severe skin ulceration as previously claimed. In general, introduced spiders are not aggressive and only bite humans if threatened or unintentionally contacted.
Taking precautions around known habitats can prevent most incidents.
Native Australian Spiders
Large and Venomous Species
Australia is home to some of the world’s most venomous and dangerous spiders. The Sydney funnel-web spider and the redback spider are perhaps the most infamous. The Sydney funnel-web is one of the most toxic spiders on Earth, with a bite that can kill an adult human in 15 minutes if antivenom is not administered.
Thankfully, no deaths have occurred since the antivenom was developed in the 1980s. Redback spiders are in the “widow” family and can deliver painful bites, though are rarely fatal. Other dangerous spiders found in Australia include the trapdoor spider, mouse spider, whitetail spider, and black house spider.
Habitats and Encounters
These spiders inhabit a variety of environments across Australia. Sydney funnel-webs prefer moist habitats like rotting logs and burrows. Redbacks often live in dry, dark places like woodpiles, sheds, and toilets. Trapdoor spiders construct burrows lined with silk in soils throughout Australia.
Mouse spiders are ground-dwellers but often enter homes. Whitetails reside in grassy areas and gardens. Black house spiders spin messy webs in man-made structures. Homeowners may encounter the latter three species indoors.
Here are some tips to avoid unwanted run-ins:
- Seal cracks in foundations and gaps around windows/doors
- Keep woodpiles and debris far from the home
- Shake out clothing/shoes left outside
- Wear gloves and long sleeves when gardening
Dangers to Humans
While Australia has some of the world’s most poisonous spiders, deaths are extremely rare thanks to the availability of antivenoms. Only 12 spider bite deaths have occurred since 1979, per the Australian Geographic. Most bites only result in mild symptoms like pain, swelling, and nausea.
Still, it’s wise to give all spiders their space and exercise caution outdoors. Parents should check play areas thoroughly and teach children not to touch the spiders.
Spider populations have generally decreased in Australia due to habitat loss. However, climate change may enable some species like the Sydney funnel-web to expand their ranges southward from Queensland per the Sydney Morning Herald.
Nevertheless, basic precautions will allow humans and spiders to safely coexist in this diverse island continent.
Side-by-Side Comparison
Sizes and Traits
There are over 2000 species of spiders found in New Zealand, but most are smaller and less venomous than their Australian counterparts. The giant weta insect can grow nearly as large as a mouse, but no spiders in New Zealand approach the size of a huntsman or bird-eating spider seen in Australia.
Some common traits of NZ spiders include:
- Most have bodies less than 1 cm in length
- They are often black, brown, or gray in color as camouflage
- Many build small webs rather than actively hunting
By contrast, Australian spiders like the giant huntsman and funnel-web can have leg spans over 10 cm and bodies over 5 cm long. Their size and speed make them more intimidating despite relatively mild venom.
Venom Potency
No spiders native to New Zealand have medically significant venom. The katipo is one of the only spiders with potent neurotoxic venom, but antivenom makes bites very treatable. Researchers estimate that “less than 1% of NZ spider species pose even mild danger to humans.”
Australia is home to several spiders with highly toxic venom that can cause severe pain, illness, or even death in rare cases. These include the notorious Sydney funnel-web and redback spiders. Funnel-web bites can kill children in under an hour without antivenom treatment.
| Spider Species | Toxicity Level | Antivenom Available |
| Katipo | Moderate neurotoxin | Yes |
| Sydney Funnel-Web | Extreme neurotoxin | Yes |
| Redback | Moderate cytotoxin | Yes |
Human Risk Levels
The risk of being bitten by a spider in New Zealand is quite low compared to Australia. One study found only 10-12 NZ spider bites needing antivenom annually, whereas thousands receive antivenom for Australian spider bites each year.
Factors contributing to lower risk in NZ include:
- Smaller average spider size and less potent venom
- Lack of aggressive, hunting spiders found in Australia
- Many harmless camouflaged web-builders versus roaming hunters
Still, basic precautions like checking shoes or gear left outside, wearing gloves in gardens, and watching for webs in sheds or woodpiles can further reduce any risk. Overall, New Zealanders can rest easier knowing there are no lethal spiders hiding in their homes.
Conclusion
While New Zealand has some native and introduced spiders that can deliver mildly venomous bites, the country fortunately does not face the same level of large, highly venomous spiders as found across the Tasman Sea in Australia.
So if you’re arachnophobic, visiting or moving to New Zealand will provide some relief compared to Australia! But do still take care around certain introduced spiders in New Zealand that can be invasive and harmful to native wildlife.
