Trap Door Spider

Photograph from my friend Jason Huntley – August 5 2012, you can see some of the silk retreat the spider emerged from.

One of our most impressive and heavy bodied native spiders is the trap door spider of the family Ctenizidae. These spiders, while not commonly encountered are not rare, it’s simply that they spend most of their lives just under the surface of the soil with a silk lid on the entrance. They generally weave a series of trip lines around the entrance so if any insects walk by they know it, and can rush out and grab their meal.

Drawing from the Arizona Sonora Desert Museum website. Genus Ummidia (same as our photo).

Trap door spiders are mygalomophs rather than the usual araneomorphs which means they are considered a bit more “primitive” in always having eight eyes, and having their jaws oriented for striking straight up and down – like ice picks. Most of the spiders pinch to bite, their fangs are opposing. Which one of the reasons why it’s hard to get bitten by most spiders. It’s a little like trying to open your mouth wide enough to take a bite out of a watermelon.

The Ctenizidae however are much like our version, in North Carolina, of a tarantula, which is to say a primitive, “ice pick” stabbing, large spider.   I want to point out that this spider is not dangerous, if you were to mishandle it, and manage to get bitten – it’d be more like a bee sting than anything wildly sensationalized on Animal Planet.

Another photograph by Jason. Showing that it is about the size of a mole. Sometimes after a heavy rain the silken retreat is washed away and the spider has to come out and found a new one. This is when they are discovered and often shock the person discovering it.

Jason also took a bit of video of his natural history interest here and uploaded it to youtube for your watching pleasure! Enjoy!

Jason’s trap door spider.

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