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The deserts of Arizona have quite a few unusual arthropods. The sight of some of them can cause visitors to hop right out of their boots. Last night I had one of those in my upstairs bathroom. Here is what I saw:

giant crab spider

It is sitting the bottom of the bathroom door, to give you some idea how big it is. What would you do if you saw this?

I have to admit I took these photos in a rush. Not because I was afraid of this giant spider, but because I was afraid our kitten might catch and eat it. I wanted to put it outside quickly in order to save its life.

giant crab spider

This is a prime specimen of a giant crab spider, one of the largest spiders around. It can easily get to be 2 inches across. Giant crab spiders don't build a web, they chase down other arthropods for food at night. Crickets are a favorite snack. They are called crab spiders because their legs extend sideways rather like a crabs.

Can you see the eyes? The big black structures in front are its chelicerae, or jaws. Although it can bite, it is not particularly dangerous. The only potentially harmful spiders we have here are black widows and Arizona brown spiders, a relative of the brown recluse.

I went and got a large glass and a card. I set the opening of the glass over the spider, slid the card under gently so I could lift it from the surface, and then carried the spider outside. It ran away into the night when I let it go. I wished it good luck.

The Arizona-Sonora Desert Museum has more information about the giant crab spider and other desert arthropods.

This morning when I was talking on the phone with my sister outside, I noticed a spider wrapping up a fly it had caught in its web. I recognized it immediately as a cellar spider, Family Pholcidae, because of its slender body, long legs and the tangled shape of its web. It also has dark markings on the underside of its body.

The larger cellar spiders common around homes in the Southwest have been introduced from Europe. This one looks like the marbled cellar spider, Holocnemus pluchei, because of the marbled white and pinkish-red pattern on its abdomen.

cellar spidercellar spider 2

We have a community of cellar spiders that live on the outside of one of the windows where we watch our bird feeder. When the feeder is quiet, we watch the spiders instead.