Spiders

Asked March 27, 2017, 2:54 AM EDT

Can any experts please tell me what kind of spiders are these (photos taken in Australia)? We don't normally see spiders around the house and all of a sudden found 2 on different windows (bedroom and living room)? 'I'm really confused why they are all here at once and I'm so terrified of them..!

Outside United States

1 Response

Thank you for your question. It can be very difficult to identify a spider based on a photograph alone, especially down to the genus and species. The best way to determine the identity of a spider is to take it to a museum or university that has arachnologists on staff that can examine your specimen and provide you with an accurate identification. I don’t know in which part of Australia you live, but the Australian Museum in Sydney, for example, has extensive information on Australian spiders on their website.

That being said, the large brown spider in your photograph looks like one of the huntsman spiders. There are several genera that occur in Australia. Huntsman spiders are often found under loose bark on trees and logs, as well as in crevices in rock or rock walls. Their bodies have two adaptations that allow them to fit in these tight spaces: their bodies are usually flattened and their legs, instead of being oriented vertically like most spiders, are oriented more laterally like a crab’s legs. Huntsman spiders are also found in homes, and in cars, where they often hide behind the sun visor, which makes sense, since the flat sun visor is similar to a piece of loose bark on a tree.

Huntsman spiders are not aggressive and will usually take every opportunity to run away if startled or threatened. Like most spiders, huntsman spiders are venomous, but their bite is not considered to be dangerous to humans.

Here are a couple of links to the Australian Museum’s website that provide additional information on huntsman spiders:

https://australianmuseum.net.au/huntsman-spiders

https://australianmuseum.net.au/spider-facts

The other spider in the remaining two photographs looks like a white-tailed spider. There are two species of this spider that are common in Australia: Lampona cylindrata and Lampona murina. According to the Australian Museum’s information, L. cylindrata is found in southern Australia, including southeast Queensland, New South Wales, Victoria, South Australia, Tasmania and Western Australia. L. murina is found in eastern Australia from northeast Queensland to Victoria.

The white-tailed spider lives underneath bark, rocks, logs and leaf litter outside, but can also be found in homes. They are primarily nocturnal and feed primarily on other spiders. This accounts for the reason they are often found in homes, because they can often find a ready supply of spiders, like the black house spider. You can reduce the chances of encountering them in your home by sweeping away the webs of house spiders that you find in your home.

According to the Australian Museum’s information, white-tailed spider bites can cause initial burning pain. This is followed by swelling and itching at the site of the bite. They also report there are unconfirmed reports of weals, blistering or local ulceration. These conditions are referred to medically as necrotising arachnidism. The media has capitalized on these reports, and represented this spider as much more dangerous than confirmed reports have suggested. A recent study of patients with confirmed bites from this spider, however, found no cases of ulceration.

Here is a link to the Australian Museum’s website with more information on the white-tailed spider:

https://australianmuseum.net.au/white-tailed-spider

Again, this information is based on what I can make out from your photographs. To ensure the most adequate identification, you should take your spiders to a local expert at a museum or university. Hope this information helps, and thank you for contacting Ask an Expert.

Jim