These lugs are nuts.

You might be a bit crazy too if you spent almost your entire life in the mud. Most likely you have never seen a lugworm, but rest assured they are down there.

Lugworms are the earthworms of the sea. They are mortals of the muck, thriving in shallow marine areas, beaches, and pond shores. Rarely do they ever see the light of day, making them “infaunal” organisms. U-shaped burrows are their homes, below the sea and sand with only their tails occasionally exposed.

This tale could end badly if their exposed tail ended up a tasty treat for birds or fish, both of which are predators of these worms. The loss of a bit of tail, though, will cause little worry, since lugworms can regrow the missing piece.

Our shorelines are chock full of lugworms. In one off-Island study, lugworms accounted for 30 per cent of the biomass on a beach. Anglers take advantage of these copious creatures since they are good bait for cod and other fish. And observant beachcombers have seen their low-tide leftovers, piles of castings in mounds on top of the sand.

These casting are the droppings of the lugworm. Lugworms eat sand and extract organic matter and edible particles within their silty lunch. Then, like smaller versions of the dredgers you see on State Beach, they dispose of the sand by piling it outside of their door — every day is garbage day for the lugworms.

But by far the most interesting lugworm litter left behind would be the giant gelatinous egg cases that they extrude for reproduction. That is the main reason that I bring up these worm wardens of the water. The lugworm usually measures less than one foot, but produces an egg case that can be much longer and three times as wide!

These egg cases are very common in our waters — I see them often in Cape Pogue Bay, Sengekontacket Pond, and Katama Bay. These egg cases look like sea cucumbers but are more loose and gelatinous, with brown eggs visible in the gelatin. When you try to lift them out of the water, these jelly tubes break up so you will end up with lots of smaller pieces of goo. Their nickname, sea snot, describes them better than I ever could.

Three varieties of these sedentary lugworms make Martha’s Vineyard their home, though many other marine worms can be found below the water’s surface. Staying put for lugworms require statocysts, which are balancing organs that keep them head-down in their burrows.

Keeping your head down while mucking through in life might not seem like much of an existence to us, but on the other hand there are worse ways to spend a life. Also, don’t be too quick to dismiss the lowly lugworm: as Hamlet observed, “A man may fish with the worm that hath eat of a king, and eat of the fish that hath fed of that worm.”

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.