Thursday, May 31, 2012

Beach hoppers

Beach hoppers' tiny legs straddle the wide transition zone between salt water and dry land. And because they do, those itty bitty legs have gills.


Some folks call beach hoppers "sand fleas," though they are not really fleas--and they don't bite. They do make impressive leaps, though, earning them the comparison. But hoppers are crustaceans rather than insects, related to the pill bugs and sowbugs found in your backyard, which are a little ahead of them on the evolutionary transition to landlubbers.


Photo by ingridtaylar 
Hoppers can neither live too far from the ocean or too close to it. Those gills on their leg joints mean that the animals require moisture to breathe. But many species are poor swimmers and will drown if submerged too long. So they live on the margin, navigating the area between dry land and lapping tide.


Hoppers are scavengers, eating what the tide tosses up, especially seaweed. Picking up a piece of bull kelp on the Pacific coast can launch an explosion of hoppers.


During broad daylight or high tide, each little beachcomber is buried headfirst in a teeny den in the sand, near the high tide line. They've sealed these with sand granules, so you're unlikely to see occupied dens. But you can look for the small round holes that were their previous day's burrows, next time you're on a sandy beach. 

8 comments:

  1. There must be hundreds of different kinds of these little guys hiding at the beach from an 1/8 inch to 1 inch. Do you know if the really little ones that bite, are there lots of different kinds or just one kind that is doing all the biting.

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  2. Yeah, there are many species of beach hoppers, but none of them bite people, to the best of my knowledge. 

    Midges (like no-see-ums) do bite people, though--and they're so small  that maybe the more obvious beach hoppers get the blame. 

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  3. And just seeing those little hoppers makes my skin crawl, so it feels like I'm being bitten.  Next time this happens, I will remind myself that I am not seaweed, and these are not fleas.  More like teensy mutant lobsters.  Yeah, that'll help me feel less creeped out.

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  4. Sooo enlightening---I doubt if I was alone in thinking sand fleas and "no-seeums" were the same thing---and did bite. So the biting ones are called midges?  Whatever they're called, they can make a trip to a South Carolina beach in June unbearable! 

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  5. see the old burrows
    beach hoppers moving about
    hiding in plain sight

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  6. My young sons and I visited a Pacific Northwest tidal mudflat yesterday, and "discovered" these little critters. Boy, was I surprised when the first one jumped! We took a couple of pictures, came home and looked them up, discovering their name and basic habits. What puzzled me, though, was that my book seemed to indicate that they are nocturnal, so we shouldn't really have been seeing them, though they were out in force. Am I correct that your post above implies they do not like *bright sunlight,* but are not strictly nocturnal, or is there a variation between beach hopper species? It was a sunny-ish day, but it was morning in the PNW, in May, so it was neither hot nor truly bright. I'd like to clear up that small mystery.

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    Replies
    1. Nighttime is when they really party, but you can see plenty of beach hoppers during day, too. There are likely some species that tolerate sunlight better than others, but I'm not well-versed enough in beach hopper culture to know which ones.

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