What's That Bug? does not endorse extermination

Subject: Swimming Pool Spider
Location: Palm Desert, CA, backyard pool
November 13, 2013 6:00 pm
Hi Daniel,
Yesterday, I was sitting on the edge of a swimming pool with 2 friends in Palm Desert, when one of the dogs jumped in the pool. A very large spider washed out from under the gray concrete ledge of the pool, right beneath my legs. We all jumped up immediately!
The spider was about 3” diameter across its legs. It was the exact color of the gray concrete. Its body was quite substantial. It seemed to be very comfortable floating around and walking on the water.
We watched for a while, as I took photos on my phone. This was the best (close up was cropped from the wide shot). When threatened, it would pull its legs in looking just like a seed pod floating on the water. I had to marvel at its clever adaptations to this pool. On a look around the pool there were good size crevices between the concrete deck & the mottled blue-gray tile where it could lie in wait for its prey. I suspect it’s an ambush predator. There was also a Ficus-like hedge that would produce beans nearby. It was a typical grass and trees So Cal Suburban backyard – not desert landscaping.
Since dogs and people were in the pool, the homeowner rescued the spider and placed it in the nearby hedge. I’m sure it would find its way back to the pool by nightfall.
Signature: Diane E

P.S.  Almost forgot – one more thing it was a saltwater swimming pool.

Possibly Fishing Spider

Wolf Spider

Nov 12
Hi Daniel,
Same color as the pool deck was lying in wait under the ledge of deck.    With legs it had a 3″ diameter & seemed perfectly happy swimming floating in friend”s pool in Palm Desert.
Diane Edwardson

or more generally a Nursery Web Spider

Wolf Spider [our crop]

Hi Diane,
Please resubmit using our standard form:  ask-whats-that-bug/
We want to post this photo but we would like any additional information you are able to provide.

Hi again Diane,
Thanks so much for resending your identification request with such a detailed account of this spider sighting in Palm Desert, California.  This sure looks to us like a Fishing Spider, but we can’t help but to wonder if it is
Trechalea gertschi, so we are copying Mandy Howe, an editor at BugGuide, to get her opinion.  We had already cropped the image you sent originally while we waited for you to resend your request.

Ed. Note:  Mandy Howe was kind enough to identify this Wolf Spider as Arctosa littoralis.


What's That Bug? does not endorse extermination
Location: Palm Desert, California

5 Responses to Wolf Spider walks on water in Palm Desert

  1. Mandy Howe says:

    Hi Daniel & Diane,
    The Palm Desert spider found on the surface of the pool is actually a large species of “wolf spider” by the name Arctosa littoralis. This one is a female. That species is normally found in sandy areas and they often blend right in to their surroundings. Some are even completely white to match white sand. They aren’t normally associated with water (aside from living on beaches sometimes), so I think this one just fell in and was doing the best it could to stay above water. Most kinds of spider can use the water’s surface tension to stay afloat for a while, but if their belly gets stuck to the water surface for too long, they will eventually drown (their lungs are on the underside of their abdomen). They can go a pretty long time without oxygen, but I’m glad to hear she was rescued! =)

  2. I have a new victim in Qld Australia. who says she was bitten in her pool of salt water is this possible and what would it look like?she thinks it was a white tailed spider/

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