Running Crab Spider

2023 January 8

These spiders are pretty common around here in the fall, considering that this first one (above) was on our house siding on October 22, 2022, and a second one (below) was on our windowsill on November 6 just a couple of weeks later.

There is some variation in color, but I think this is within the normal range of variation and they are both the same species. And, in fact, they are most likely the same species as one that we caught on the windowsill almost exactly a year earlier. I believe these are all Running Crab Spiders in the genus Philodromus, and in fact I think they are most likely Philodromus praelustris. And, judging from their small abdomens, large pedipalps, and the fact that they were all roaming around, they were also all males.

Here’s a closer view of the first one, you can see his two anterior median eyes looking almost straight up. Unlike the cobweb-weaver spider last week, these eyes aren’t reflecting the camera flash because these spiders don’t have a tapetum in their eyes.

Swinging a bit more around to his face, you can see that his other eyes are not particularly large, implying that his vision is not so great in general.

I had the second one on a plate on the table, so I was able to get a better view of his face,

and also one from the side so that we can see how flat they are compared to some other spiders.

I think they like to hide under bark and leaves, and pounce on their prey, using their relatively long four front legs to grab them. You might notice that the second spider is missing one of his four front legs, as was the one I photographed a year earlier. This suggests that if they pounce on something that puts up too much of a fight, they are likely to lose one of those legs.

Being a spider sounds like it is sometimes hard work, and quite dangerous.

One Response
  1. January 15, 2023

    Great photography as always! It makes me want to run a very tiny comb through their hair. 🙂

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