Wednesday is science day for this blog site, and today I reach into my bag of odd creatures and select the horseshoe crab.  The odds are high that you have never seen one. There is an Atlantic species that lives along the coastline from Maine to the Yucatan Peninsula. There are three other species, mostly found in Southeast Asia. Coastal areas having none of them:  Europe, Africa, South America and large parts of Asia and the Pacific. Aquariums generally don't have them.  These are Kujukushima horseshoe crabs at the Saikai National Park in Japan on Kyushu near Sasebo. They spend most of their lives in deep, offshore waters, only coming to shallow coastal beaches to spawn during high tides at night during full and new moons. There has been habitat destruction. Another reason is that, where they are found, large-scale and unregulated operations have killed them off. From the 1850s to the 1960s, millions of horseshoe crabs were annually harvest primarily for use as fertilize...