Giant Spiders

Welcome back to Ask a Naturalist, your own personal Google for information on all things natural on PEI. Apologies to my fellow arachnophobes, but I’ve been getting questions about some BIG spiders on the Island and thought we should take a look!

No matter where you are right now, there’s likely a spider nearby. These remarkably adaptable animals are found in every habitat and on every continent (yes, even Antarctica!). Nearly 200 species have been recorded on PEI, and there are more yet to be found.

Spiders are not only extensive, they’re also abundant. I’ve seen one estimate of more than two million spiders per acre in grassy, late-summer fields in England; even if you think our cold Canadian climate might host fewer, that’s still a lot of spiders! One look at the glistening, dew-covered webs in the morning sun gives you an idea. But while they’re everywhere, it’s the larger ones that get the most attention.

Photo 1: A Giant House Spider (Eratigena atrica complex). Photo by Phil Taylor, used with permission. Although this photo comes from Nova Scotia, we have confirmed records of this spider on PEI as well.

The well-named Giant House Spider (Eratigena atrica complex) is native to Europe but arrived in Canada more than a century ago. It’s been present here in the east since the 1990s and is now found in all three Maritime provinces. This photo (left) comes from Nova Scotia, but I like the household objects at the bottom that give a nice sense of scale (Photo 1 by Phil Taylor, used with permission).

Giant House Spiders can be as big as 10 cm (four inches) across including their legs, and are known for being fast by spider standards – up to 0.5 metres per second (which sounds much more impressive than the equivalent 1.1 miles per hour). While they may seem like unwelcome house guests, they do provide valuable pest control services and aren’t aggressive towards humans. All spiders are venomous, but even if you annoy a Giant House Spider enough to get bitten it’s unlikely to cause any real harm.

Photo 2: A Dark Fishing Spider (Dolomedes tenebrosus) on PEI. Photo by Raquel Wells used with permission

The second large, local spider of the day is a Dark Fishing Spider (Dolomedes tenebrosus, Photo 2 by Raquel Wells used with permission). This is a female, which can reach 7.5 cm (about three inches) including legs, and is roughly twice the size of a male. While only a few Giant House Spiders have been confirmed on the Island, Fishing Spiders are more common.

Despite the name, Dark Fishing Spiders aren’t restricted to areas near water. They can be found in woodlands far from streams or ponds, and it’s not unusual to meet them indoors if you have woodland or wetland habitats nearby.

Fishing Spiders feed on insects, other spiders, slugs, small amphibians, and anything else they can catch (including small fish). These are ambush predators, using sensitive hairs on their legs to detect vibrations from prey and then pouncing. As ominous as that sounds, these native spiders are no danger to humans and are themselves prey for larger amphibians, reptiles, and birds.

If knowing that PEI has spiders larger than you thought creeps you out, be glad I didn’t tell you some of the more colourful stories that go along with them. (Like the person who heard the tip-taps from a Giant House Spider’s feet before he saw it!).

If you have a question about PEI’s wild side, it’s likely others do too! So, follow me here or on Facebook and Instagram, join the conversation, and Ask a Naturalist about PEI untamed!