Next time you head to the beach, be sure to keep an eye out for the gray, wiggling bodies of mole crabs. Aptly named for their ability to burrow in the saturated sand of the changing tides, the egg-shaped mole crabs have bodies made for the crushing forces of the intertidal zone.

With a habitat range from Alaska to Argentina, the Pacific mole crab (Emerita analoga) is an abundant crustacean that lives in large populations (shoals) on beaches spring through fall. About 1.5 inches in length, the mole crab is without spines or claws and instead uses leaf-like leg appendages to propel backwards through water and dig into the sand. These same fluttering appendages help anchor the crab while buried in the sand and withstand constantly shifting sands, crashing waves and seasonal variations in marine tides. In order to feed and breath, two sets of highly-functional feathery antennae unfurl to capture plankton and snorkel in the push and pull of the ocean waves.

It is incredible to watch the mole crabs swim and dig along the shoreline and find both males and females. Male crabs live higher on the beach and are smaller while females can carry more than 20,000 visible bright orange eggs along the underside of their larger bodies. Once hatched, the free-swimming mole crab larvae are transported with ocean currents for three to six months and then wash up onto beaches as juveniles.

Predators of the mole crab include fish, birds and marine mammals such as otters. Early-summer is a great time to watch shore birds such as the whimbrel scurrying after stranded mole crabs as the waves recede. Whimbrels are a common visitor to the Oregon Coast and are one of the most common and well-traveled curlew species. Mole crabs help sustain these abundant shore bird populations.