Connecticut Audbon Society


I Spy: Coastal Connecticut Past Mysteries

Here is our archive of past I Spy: Coastal Connecticut mysteries. Scroll down to see the mysteries, its answer and some fun facts about the organism.






May 25 – Can you guess what this is?








The Answer for they May 25 Mystery is……








If you guessed Horseshoe Crab, you are correct!

This is one of our favorite creatures that lives in the Long Island Sound!


Did you know?

  1. Horseshoe crabs are marine and brackish water arthropods of the family Limulidae.
  2. Horseshoe crabs get their name because their arc shaped carapace, or exoskeleton, has been compared to the shape of a horse’s shoe.
  3. Horseshoe crabs live primarily in and around shallow coastal waters on soft sandy or muddy bottoms.
  4. Given their origin 450 million years ago, horseshoe crabs are considered living fossils.
  5. The earliest horseshoe crab fossils are found in strata from the late Ordovician period, roughly 450 million years ago.
  6. The Atlantic horseshoe crab has two small legs (chelicerae) for moving food into the mouth and five large pairs of legs for moving.
  7. Females are about 20–30% larger than males
  8. Horseshoe crabs use hemocyanin to carry oxygen through their blood. Because of the copper present in hemocyanin, their blood is blue.
  9. In the Spring, Horseshoe crabs migrate to shallow water near the shore, the female digs a hole in the sand and lays her eggs while the male(s) fertilize them. The female can lay between 60,000 and 120,000 eggs in batches of a few thousand at a time.
  10. Horseshoe crabs are more related to spiders, ticks, and mites, than they are to crabs. There are only four living species of horseshoe crabs today. Limulus polyphemusresides on the eastern coastline of North and Central America. (Project Limulus-Sacred Heart University Website)

If you are interested in learning more about Horseshoe Crabs visit Project Limulus on the Sacred Heart University Website–schools/college-of-arts–sciences/departments/biology/project-limulus/horseshoe-crab-history/






May 18 – Can you guess what this is?




The Answer for the May 18 Mystery is……

If you guessed Mussel , You are Correct!!!

Did you know?

The mussel’s external shell is composed of two hinged halves or “valves”. The valves are joined together on the outside by a ligament, and are closed when necessary by strong internal muscles (anterior and posterior adductor muscles.

Mussels are bivalves are are mostly browish-black exterior with irredescent inner shell.

Like most bivalves, mussels have a large organ called a foot. In marine mussels, the foot is smaller, tongue-like in shape, with a groove on the ventral surface which is continuous with the byssus pit. In this pit, a viscous secretion is exuded, entering the groove and hardening gradually upon contact with sea water, creating the byssal threads.

Byssal Threads are used to secure the mussel in place making it more difficult for predators to remove.

Mussels live in colonies in salt marshes or bays where the water is more calm.

In marine mussels, fertilization occurs outside the body, with a larval stage that drifts for three weeks to six months, before settling on a hard surface as a young mussel.

Mussels are filter feeders; they feed on plankton and other microscopic sea creatures which are free-floating in seawater. A mussel draws water in through its incurrent siphon. The water is then brought into the branchial chamber by the actions of the cilia located on the gills for ciliary-mucus feeding. The wastewater exits through the excurrent siphon.

In roughly 12–15 months, mussels reach marketable size (40mm) and are ready for harvest

Humans have used mussels as food for thousands of years. About 17 species are edible.  Mussels can be smoked, boiled, steamed, roasted, barbecued or fried in butter or vegetable oil. 


May 11 – Can you guess what this is?








The Answer for the May 11 Mystery is……

If you guessed Mummichog, Fundulus heteroclitus, Atlantic killifish, mummies, gudgeons, or mud minnows… you are correct!

Did you know?

  • You will find these fish in brackish and coastal waters including estuaries and salt marshes
  • This species is hardy and has the ability to tolerate highly variable salinity, temperature fluctuations from 43 to 95 °F, low oxygen levels, and heavily polluted ecosystems. As a result, the mummichog is a popular research subject
  • It is the first fish ever sent to space, aboard Skylab in 1973
  • They are found along the shore from Florida to Nova Scotia
  • Mummichogs are omnivorous. Analyses of their stomach contents have found diatoms, amphipods and other crustaceans, molluscs, fish eggs (including their own species), very small fish, insect larvae, and bits of eelgrass
  • The maximum length is 5 to 6 inches, but adult mummichogs are seldom more than 3½ to 4 inches long
  • Some fishermen use them as bait
  • The mouth is upturned and the lower jaw protrudes when the mouth is closed. Pectoral and tail fins are round. Mummichogs have 10-13 dorsal fin rays, 9-12 anal fin rays, 16-20 pectoral fin rays. Males have larger dorsal and anal fins than females.



May 4– Can you guess what this is?












The Answer for the May 4 Mystery is……

If you guessed Hermit Crab you are correct!

Did you know:

  • Most species have long, spirally curved abdomens, which are soft, unlike the hard, calcified abdomens seen in related crustaceans.
  • Most frequently, hermit crabs use the shells of sea snails
  • The tip of the hermit crab’s abdomen is adapted to clasp strongly onto the columella of the snail shell.
  • The columella (meaning “little column”) is a central anatomical feature of a coiled snail shell.
  • Most hermit crabs are nocturnal.
  • They breathe through gills but they don’t have to be in water. Most can survive for a short period of time out of water as long as their gills are damp. 
  • As Hermit Crabs grow, they must abandon their shell and look for a larger shell to fit their growing body. If the shell they find is too big the Hermit Crab will wait near the new shell, but if another Hermit Crab comes along and fits the shell that he was waiting for, the waiting Hermit Crab will take the shell from the other crab when the shell is abandoned for the new shell.
  • Hermit crabs need lots of friends! They thrive in large colonies, where they often sleep piled up together. They enjoy climbing, foraging, and exploring, and they even collaborate in teams to find food.
  • Hermit crabs can live for more than 30 years in their natural habitats.




April 27– Can you guess what this is?









The Answer for the April 27 Mystery is……

If you guessed Slipper Shell, Lady Slipper, Boat Shell, Atlantic Slipper Limpet or Crepidula fornicate…you are correct!


Did you know:

  • Slipper snails are often found it stacks or piles—the oldest and largest at the bottom of the pile are female, the younger small animals at the top are male.   If the females in the stack die, the largest of the males will become a female.
  • They can be found as far north as Nova Scotia to as far south as the Gulf of Mexico
  • Common slipper shells are commonly found on the shoreline and in estuaries.
  • Their mucus covered gills trap phytoplankton in the water. The snail uses its radula (like a toothed tongue) to transfer the food to its mouth. Filter feeder similar to a mussel or clam.   

Not that I would eat this or even recommend eating them, they are edible…I found this recipe online, seems like a lot of work getting those snails out of the shells for not much of a reward!  No Thank You!


3 cups tomato sauce, preferably homemade

1 cup slipper shell meats, chopped

2 cloves garlic, finely chopped

3 tablespoons Italian parsley, minced

2 tablespoons olive oil

red pepper flakes to taste

1 pound linguine, cooked

Heat up tomato sauce in a large, heavy-bottomed pot. Add all ingredients but the linguine. Simmer for three minutes and serve over the linguine.




April 20– Can you guess what this is?















The Answer for the April 20 Mystery is……

If you said Asian Shore Crab, you would be correct!



  • The Asian Shore Crab also known as the Japanese shore crab is indigenous to waters from southern Russia to Hong Kong.
  • The Asian (Japanese) shore crab is invading Long Island Sound and crowding out native species, according to marine biologists.
  • Asian shore crabs grow to about the size of a silver dollar. The crab’s identifiable features are a small hard bubble at the crux of its claws; three spines along each side of its shell carapace and a light-and-dark banding pattern on its legs.
  • This species has a very broad diet, it has the potential to affect populations of native species such as crabs, fish, and shellfish by disrupting the food web.
  • It is believed by scientists that the Asian Shore Crab was introduced to the United States by larvae attached to the bottom of ships and in ballast water arriving from Asia.
  • The breeding season is from May to September, and females can bear two to four broods of eggs, producing around 50,000 eggs per spawning.
  • The Asian Shore Crab is found from the coast of Maine to North Carolina.
  • In 2008 a law was passed that all ships entering U.S. waters must put chemicals in their ballast to kill any foreign organisms to prevent invasive species from being dumped into the water.




April 13 –  Can you guess what this is? 













The Answer for the April 13 Mystery Is…..

If you guessed Fiddler Crab, you are correct.

Did you know:

  • Male Fiddler Crabs have one large claw and one small claw
  • Female Fiddler Crabs are smaller and have two small claws
  • The largest fiddler crabs only reach a mature size of about 2 inches across their body.
  • Fiddler crabs play a vital role in salt-marsh ecology because their feeding and burrowing helps keep marshes clean and helps them to grow. They are natural aerators so to speak. They feed by sifting through the sand and mud for algae, bacteria, and decaying vegetation, Leave behind little balls of “clean” mud/sand near the burrow opening.
  • Fiddler crabs also have gills, like a fish, so they can live underwater. But they have a (basic)primitive lung that lets them breath on land, too.
  • Fiddler Crabs live in individual burrows within a colony.
  • When the tide rolls in, they plug the burrow hole with mud (kind of like closing the front door) so the water can’t get in, once the tide goes out, fiddler crabs will open the mud plug and come out for a meal!
  • They are called Fiddler Crabs because when a males feed, the back-and-forth movement of its small claw (from the ground to its mouth) near its large claw resembles the motion moving a bow across a fiddle.



April 6 – Can you guess what this is?













The Answer for the April 6 Mystery Is …

If you guessed Oysters, you are correct!


Did you know:

  • Oysters are bi-valve mollusks and are filter feeders.
  • Oysters have gills which have beating hair-like structures called Cilia, the beating action of cilia pumps water in and out of the shell through valves, not only helps the oyster “breath” but it also brings food to the oyster and carries out the waste through valves.
  • Oysters cement themselves to each other in large clumps and are found in areas of rock and shells which forms an oyster reef.
  • Oyster reefs provide an effective natural barrier to storm waves and sea level rise.
  • A single Oyster can filter 50 gallons of water every day and a healthy one-acre reef around 24 million gallons.
  • In captivity they can live up to 20 years
  • Once the female is fertilized, she discharges millions of eggs into the water. The larvae remain suspended in the water column as larvae for two to three weeks before settling on a bed. When oyster larvae settle on in their bed, it is called spat.

So, as you can oysters are an important part of a healthy ecosystem. They are also delicious to eat!

For the history of oysters in Connecticut visit the link:  Oystering in Connecticut From Colonial Times to Today







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