Arachnophobes beware! The Sacramento River has been taken over by big, black spiders.

Well, not really. But, as almost everyone who walks the Sacramento River Trail has noticed, there has been a tremendous increase in both spiders and webs in the last month.

It is part of the cycle of life on the river, according to Jerome Rovner of the American Arachnological Society. We found Mr. Rovner through the Internet and he was kind enough to identify the spiders and answer some questions.


The spiders in the pictures we sent him are orbweavers (Arabesque Orbweavers to be exact). They have a 1-year lifespan and generally spend the winter as eggs in egg sacs, hatch in the spring and build small webs in low vegetation as juveniles. They attain their adulthood in the summer and take over the trees.


Life is not easy for these daunting creatures, despite the multitudes of small, winged insects upon which they feed.

wasp eats spider


They are hunted by wasps (mud daubers) and birds, pirate spiders and even Thread-Legged Assassin Bugs. Hummingbirds sometimes steal their silk to make their nests and kleptoparasitic spiders and scorpion flies steal their wrapped prey.


But that doesn’t mean they are defenseless. Although Rovner lets the largest ones crawl on his hand, they will bite if you squeeze them. He said the defensive bite is no worse than a bee-sting.

For the somewhere between 3.5 and 6.1 percent of us who are arachnophobes (according to Wikipedia), that probably won’t make any difference at all.

Pity the spiders, which don’t seem to warrant an annual count, as birds do. Are there more spiders this year than before? We may never know for certain.

Bill Siemer

Bill Siemer

Bill Siemer grew up on a farm in Lassen County, played basketball at Shasta JC, went to Vietnam, became a newspaper reporter and then a lawyer and now considers himself a champion of the story that needs to be told. He lives on the bank of the river and takes pictures.

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