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This morning I was teaching lab when three of my students in the back corner called me over to where they were working. "We have a problem," one of them declared.

Since they were making posters I assumed that the problem had to do with format or content or something related to the scientific papers they were analyzing. When I got back to them and asked what the problem was, they just pointed at the corner of one of the counters. "You've almost put your hand on it," one of them said.

I looked under my hand . . . nothing. "No," the student continued, "it's under the edge."

I looked under the lip of the counter and there was a tiny spider just starting to lower itself on an invisible strand of silk. And I do mean tiny: the entire body would have fit onto my thumbnail, with room to spare. Seeing that it was a jumping spider and nothing to be afraid of, I captured it in my hands and released it outdoors. Meanwhile, the students cowered and kept their distance.

Here's the only picture I was able to take before returning to the classroom. I was supposed to be teaching, after all.

Red-backed jumping spider (Phidippus johnsoni). 4 December 2015 © Allison J. Gong
Red-backed jumping spider (Phidippus johnsoni).
4 December 2015
© Allison J. Gong

Intrigued as I usually am by something I don't know much about, I looked up California jumping spiders after class. I knew it was a jumping spider because I've seen many of them before, and they really can jump. This little one, measuring maybe 1 cm in total length, jumped about 10 cm when I put it on the railing outside. Then it scurried to the edge of the railing and went overboard. Jumping spiders are super cute. If you don't believe me, ask the almighty Google to show you some mating dances of male jumping spiders. I dare you not to be impressed.

Jumping spiders belong to the appropriately named family Salticidae. They are little spiders, rather hairy, with shiny black eyes. Because of their small size they often don't provoke the knee-jerk "KILL IT!" response except from true arachnophobes. The one my students found today is, I think, a female red-backed jumping spider (Phidippus johnsoni). Both sexes in this species have a red abdomen; in males it is solid, while the females have a black stripe running down the center.

All spiders are hunters, capturing prey by various means and killing it with a venomous bite before slurping up the juicy insides. A little jumping spider could bite a human, but I've handled many of them and have never been bitten. The trick, I think, is not to make the animal feel threatened. If it perceives your hand as just another surface to crawl on, it won't waste its venom on you. Not that I would try this with a spider known to have a bite that is dangerous to humans, mind you. Jumping spiders often end up inside houses, though, and it's good to know that you can gently pick them up and put them outdoors where they will be happier. You might also be happier, knowing that the spider isn't inside with you!

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