Orchard Beach Pelham Bay Park, Bronx, NY. Photo by Chris Arenella
Horseshoe crabs are perhaps the most misunderstood and under-appreciated creatures on earth. Until a recent study and field trip, I, too, knew nothing about the empty, large brown shells occasionally found on beaches in New York and New Jersey. I learned that those were the shells of the unfortunate ones who found themselves on their backs and couldn’t turn back over. When that happens, they are vulnerable to seagulls who are always nearby waiting.
They predate the dinosaur by approximately 200 million years, making them 450 million years old. According to Wikipedia: Horseshoe crabs are marine arthropods of the family Limulidae and order Xiphosura or Xiphosurida. (It’s not exactly a cozy description.)
Horseshoe crabs live at the bottom of shallow ocean waters, they swim upside down, and come ashore on beaches to romantically mate during the full moon from May to July. The females are larger than the males. Males choose their mates by attaching themselves to the backs of the females. I have seen 3 males attached to one female (see my photo above). The female lays her eggs in the sand, and they are fertilized by one or many males and then hatch about two weeks later.
Horseshoe crabs do not have hemoglobin in their blood, but instead use hemocyanin to carry oxygen. Because of the copper present in hemocyanin, their blood is blue. Medical science has discovered that their blood contains amebocytes, so it is used for the detection of bacterial infection in medical applications. Horseshoe crabs are actually protected for that reason.
They are harvested, their blood is collected, and afterwards they are released back into the ocean. As a result of that tramua, their mortality rate is estimated to be as high as 30%.
As with any animal, Wildlife Watch would like to see safer, more reliable sources of amebocytes that would not necessitate the use of any living being. The reasons given by a major distributor of horseshoe crab blood is that getting approval for synthetic alternatives is costly and time consuming. Yet, we should be moving in that direction. As horseshoe crabs have been used by anglers as bait, there are many other factors that could impact their population. Further, little is known about their place in the ecological realm.
Horseshoe crabs live at the bottom of shallow ocean waters, they swim upside down, and come ashore on beaches to romantically mate during the full moon from May to July. The females are larger than the males. Males choose their mates by attaching themselves to the backs of the females. I have seen 3 males attached to one female (see my photo above). The female lays her eggs in the sand, and they are fertilized by one or many males and then hatch about two weeks later.
Horseshoe crabs do not have hemoglobin in their blood, but instead use hemocyanin to carry oxygen. Because of the copper present in hemocyanin, their blood is blue. Medical science has discovered that their blood contains amebocytes, so it is used for the detection of bacterial infection in medical applications. Horseshoe crabs are actually protected for that reason.
In my opinion, mankind owes a great debt of graditude to these slow moving and gentle crabs who don’t even bite. For that reason, and the fact that I find them endearing, I have taken on the stewardship of the horseshoe crab. I have made many trips to the beach to monitor them, and have contacted the NYC Parks Department to enlist their help with signs. If you see a horseshoe crab on his or her back, just flip her over and gently nudge her back into the water. You’ll have saved a precious life. If you’d like to help them, please contact me via Wildlife Watch: wildwatch@verizon.net.
Chris Arenella became a horseshoe crab steward during her Urban Naturalist program at the New York Botanical Garden.