We were surprised to find an almost perfectly preserved skeleton of a shore bird, some vertebrae of dolphins, the scapula and a fragment of skin from a male California sea lion, and the wing bones of a pelican. Crossing the dunes we discovered a wide variety of plants: the knubbly cylinders of iodine bush, the horned projections of the dried seedpods of the devil's claw, and the rattling bladder pods of locoweed (an Astragalus species). The vine milkweed not only had fragrant blooms, but also dried pods with fluffy tufts for seed dispersal by the wind.
Cresting the last dunes, the Pacific Ocean stretched before us. Visible through a spotting scope, a reddish egret fished in the shallows. Scattered about on the sand were lovely Venus clams (Pitar lupanaria), with their deeply grooved concentric growth lines and long spines on the posterior edge of the shell (see photograph). These bivalves begin life with an extremely different morphology, floating in the plankton. They eventually grow enough to metamorphose (undergo a radical transition) and begin their bottom-dwelling life. The rings visible in the picture are growth rings of the shell. The oldest part of the shell is up at the bump, or umbo, and the youngest part of the shell is the curved edge. The long spines of the shell are thought to aid in stabilizing the shells in their ever-shifting sandy habitat. Looking closely at each of these three shells, you can see small circles in the youngest region. These circles are a clue as to how these shells died: they were drilled by a moon snail! This carnivorous snail uses a combination of chemical and mechanical means to slowly carve out an opening in their prey. This process can take over a day, but provides a scrumptious reward for the persevering snail as they then consume the soft insides of the bivalve.
Returning to the Sea Bird we headed of into the open ocean, smiling down at Pacific white-sided and later common dolphins that rode our bow waves.
