Mole Crab

Mole Crab

The Mole Crab or Sand Bug Emerita talpoida lives on ( or rather in ) ocean beaches, burrowing in the surf zone, and at times free swimming. It is totally harmless and grows to 1.5". These odd and somewhat comical little creatures seem to do everything in reverse - they dig backwards, walk backwards, and swim backwards. Fishermen dig them up for bait.

Mole Crab
Mole Crab

Sand Bugs filter feed with their long feathery antennas, which are withdrawn into protective sheaths when not in use. Not the long eye stalks that allow the animal to remain completely buried, and the short powerful limbs. They are unable to walk in any conventional sense, but are powerful diggers, and also surprisingly swift ( if somewhat random ) swimmers.


waves

Ocean waves are created by wind ( in unique instances, waves may also be created by earthquake, landslide, or other major disturbance, but that does not concern us here. ) The factors in the mechanics of wave creation are wind speed and duration, and fetch.

Fetch is the distance over which the wind acts on the water. The longer the fetch, the greater the wave-building action. Similarly, the greater the wind speed, the greater the wave-building action. Winds are named for the direction they blow from, not to. Therefore, a west wind blows out of the west, toward the east. Predicting wave heights based on wind conditions is even today extremely imprecise - the weather service still gets it wrong about half the time.

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