At Large : Something's going on here
By Doug Cabral
Published: June 26, 2008
Diesel, the mastiff, loves the beach. It's his favorite place to walk. Lots of smells, I suppose. And swimming. He loves to swim.
Then there are the gulls, the cormorants, and the geese, all of which attract his enthusiastic attention. He has made some of his longest swims in pursuit of geese, who leisurely - and, I think, calculatedly - paddle away, luring him ever farther from the shore. His swimming skills are considerable, and mostly I don't worry, but he does not seem equipped to recognize the geese's villainy. When he gives up the chase and turns for the beach, his expression suggests no regrets, only amiable consternation at the perfidy of some species. His great head breasts the waves, there is no disappointment in his honest, black eyes. If he has a thought in mind, it may be about the shaking that he will do when he gets close enough to me to make it count.
The other afternoon, along the Aquinnah shore of Menemsha Pond, Diesel was surprised, as was I, by the mostly empty carapaces of dozens of Limulus polyphemus. Everyone has come across the shell of a horseshoe crab - never anyone home, in my experience - while walking along the shore. But, on our walk along the edge of the pond, Diesel might have encountered 100 or more empty, or nearly empty, remains. Some were overturned just above the high water line. Some were buried in seaweeds tossed up by the relentless southwester that drove mini-breakers toward the beach. Some were right side up and wiggling in the shallows, and Diesel knew instinctively that they were dangerous. For an animal of 180 or so pounds, with gigantic teeth, and serious claws at the ends of long, arched toes, Diesel is no aggressor. He leads with his nose and does a four-legged backwards leap when the water wiggles the crab's tail. If I take the risk and touch the remains, Diesel will slip up alongside me and touch the former crab with his wet, black nose. But, he's not convinced it's as innocent as I think it is.
We've happened on the beach at the conclusion of the spring spawning season for female horseshoe crabs. Their activities have naturally captured the imaginations - maybe too generous a term - of the male crabs. Out of the muddy waters, the females headed up the shore where they dug nests and filled them with eggs. They dragged the smaller males, who waited at the water's edge for the pheromone summons, up to the nests so the males could fertilize the eggs and help protect them with sand, which doesn't work very well. Birds feasted on the fertilized eggs and, as the nearby remains of clams and scallops testify, on any of the assorted bivalves hurled up into the shallows by the waves.
These festivities were a prelude to molting season, which has decorated the beach with abandoned shells. No matter how wary Diesel is, you and I know he has nothing to fear from these shells. Their moments of utility have come and gone. Most of the abandoned carapaces were shed by older crabs. Did you know that by the time a crab is 11 years old, it will have molted 18 times, which may explain what looks like the aftermath of a vicious battle between Limulus legions on Menemsha's shore. These ancient creatures, older than flying insects, dinosaurs, and man, have seen a lot, but they know only a little. They know what they know, and they can't learn something new. Diesel has his intellectual limits, naturally enough. He's cautious about the strange creatures he doesn't need to be cautious about. But, he's smart enough to let me lead the way toward something he doesn't understand and from which he is prepared to flee. And, he can learn something new, once in a while.
We also found three mesh trays, two of them with a collection of mussels and small clams inside. The trays were buoyed along two sides with foam sponsons that were torn and nearly detached. One was tethered to a round blue float, labeled "Eelgrass Restoration Project." The other two were aground and untethered. Diesel was uneasy about these trays, because the torn flotation tubes were waving back and forth in the water. And he was distracted by the shorebirds that hovered nearby, watching as we prowled in what was their dining area. While Diesel and I inspected everything we found along the pond shore, there were no swimmers, sunbathers, walkers, or boaters at the beach. It's not an in-demand swimming beach, I suppose, though our discoveries suggest it's at life's very center for a wide variety of interdependent creatures.
