The crustaceans (Crustacea) are a large group of arthropods, comprising approximately 52,000 described species. They include various familiar animals, such as lobsters, crabs, shrimp, crayfish and barnacles. The majority are aquatic, living in either fresh water or marine environments, but a few groups have adapted to terrestrial life, such as terrestrial crabs, terrestrial hermit crabs and woodlice.
CRABS
Florida's beaches are home to many sea creatures but one you've most likely come across at one time or another is the crab. These little guys can burie themselves in the sand next to you or be caught running at top speed passed your feet. They come in and out with the tide or just hang out eating in the seaweed line. Learn about the interesting and different species our little crab friends.
THE GHOST CRAB
Ghost crabs live in burrows along the sandy beaches of the Eastern United States. The crabs can reach relatively large sizes of over 50 mm carapace width. They are omnivorous and will eat other crabs, clams, insects, vegetation, and detritus. Feeding activity takes place at night, while burrowing occurs during the day. Burrows show zonation with young crabs found closer to shore, near water. Older crabs tend to burrow farther from water. The large eyes of the crab are sensitive to changes in light intensity. The crab can produce 3 sounds: a rapping of the claw on the substrate, a rasping stridulation of the legs, and a bubbling sound presumably produced from the gill chamber. Combat between males is highly ritualized and rarely ends with contact.
Ghost crabs hibernate during the winter, holding their breath for six months, by storing oxygen in sacs near the gills. They can also have a natural filter system which gathers oxygen from the air humans breath, enough to survive for one year without entering into water.
These crabs are called ghosts because of their ability to disappear from sight almost instantly, scuttling at speeds up to 10 miles per hour, while making sharp directional changes. These creatures have two black eyes, with sharp 360° vision which they use to see flying insects and catch them in mid air. The ghost crab, however, cannot see directly up, so it must burrow into the ground to prevent birds from catching it.
FIDDLER CRAB
Found in mangroves and on sandy or muddy beaches of West Africa, the Western Atlantic, Eastern Pacific and Indo-Pacific, fiddler crabs are easily recognized by their distinctively asymmetric claws. It is the males which boast an oversized claw or cheliped; it plays a role in courtship and signalling among conspecifics. The movement of the smaller claw from ground to mouth during feeding inspired the crabs' common name; it appears as if the animal is playing the larger claw like a fiddle.
Reaching a diameter of between 1–2 inches. fiddler crabs may be tan, blue-green, turquoise, black, yellow, or orange in colour. Diurnal animals, fiddler crabs are actually a darker color by day than they are by night. They are an important source of food for shore birds and other animals inhabiting salt marshes. The crabs make burrows up to 23 inchesdeep in the muddy substrate to which they retreat during high tides. When the tide is out, fiddler crabs tirelessly scurry sideways along the beach as they comb the sands for food.
Fiddler crabs live rather brief lives of no more than two years (up to three years in captivity). During courtship, the males wave their oversized claws high in the air and tap them on the ground in an effort to attract females. Fights between other males will also occur, which are presumably meant to impress the females; if a male loses his larger claw, the smaller one will begin to grow larger and the lost claw will regenerate into a new (small) claw. For at least some species of fiddler crabs, however, the small claw remains small, while the larger claw regenerates over a period of several molts, being about half its former size after the first molt.
The female fiddler carries her eggs in a mass on the underside of her body. She remains in her burrow during a two week gestation period, after which she ventures out to release her eggs into the receding tide. The larvae remain planktonic for a further two weeks.
Fiddler crabs are occasionally kept as pets.
FLORIDA STONE CRAB
Description
The stone crab's carapace is 3 to 3½ inches (7 to 9 cm) long and about 4 inches (10 cm) wide. They are brownish red with gray spots and a tan underside, and have large and unequally-sized chelae with black tips. In addition to the usual sexual dimorphism exhibited by crabs, the female Florida stone crabs have a larger carapace than males of a similar age, and males generally have larger chelae than females. 
Ecology
Florida stone crabs prefer the bottoms of bays, oyster reefs, and rock jetties where they can burrow or find refuge from predators. Juveniles do not usually dig burrows, but instead hide among rocks or in seagrass beds. It is dark brownish-red with gray interspersed. The claws are hinged, very dark, and banded with red and yellow. Adult Florida stone crabs make burrows in mud or sand below the low tide line, lying in wait for prey.
Florida stone crabs prefer to feed on oysters and other small mollusks, polychaete worms, and other crustaceans. They will also occasionally eat seagrass and carrion. Predators that feed on stone crabs include horse conch, grouper, sea turtles, cobia, octopuses, and humans.
Sexual maturity is reached at one year. Their long spawning season lasts all spring and summer, during which time females produce 500,000 to 1 million eggs. The larvae go through six stages in about 36 days before emerging as juvenile crabs. Their lifespan is seven to eight years.
The male Florida stone crab must wait for the female to molt her exoskeleton before they can mate. After mating, the male will stay to help protect the female for several hours to several days. The female will spawn four to six times each season.
The Florida stone crab loses its limbs easily to escape from predators or tight spaces, but their limbs will grow back. When a claw is broken in the right place, the wound will quickly heal itself and very little blood is lost. If, however, the claw is broken in the wrong place, more blood is lost and the crab's chances of survival are much lower. It only takes about one year for the claw to grow back to its normal size. Each time the crab molts, the new claw grows larger.
The larger of the two claws is called the "crusher claw". The smaller claw is called the "pincer claw". If the larger crusher claw is on the right side of the crab's body, the crab is "right handed". If the crusher claw is on the left side of the crab's body, it is "left handed". Since crabs' eyes are on stalks, they can see 360°. A large crab claw can weigh up to half a pound.
LOBSTER
Clawed lobsters compose a family (Nephropidae, sometimes also Homaridae) of large marine crustaceans. Lobsters are economically important as seafood, forming the basis of a global industry that nets US $1.8 billion in trade annually.
Though several different groups of crustaceans are known as "lobsters," the clawed lobsters are most often associated with the name. Clawed lobsters are not closely related with spiny lobsters or slipper lobsters, which have no claws (chelae), or squat lobsters. The closest relatives of clawed lobsters are the reef lobster Enoplometopus and the three families of freshwater crayfish.
Biology
Lobsters are invertebrates, and have a tough exoskeleton, which protects them. Like most arthropods, lobsters must molt in order to grow, leaving them vulnerable during this time. During the molting process, several species may experience a change in color.
Lobsters live on rocky, sandy, or muddy bottoms from the shoreline to beyond the edge of the continental shelf. They generally live singly in crevices or in burrows under rocks.
Lobsters typically eat live food, consisting of fish, mollusks, other crustaceans, worms, and some plant life. Occasionally, they will scavenge if necessary, and may resort to cannibalism in captivity; however, this has not been observed in the wild. Lobster skin in the stomachs of lobsters has been found before, although this is because lobsters will eat their shed skin after molting [1]. Lobsters grow throughout their lives and it is not unusual for a lobster to live for more than 100 years. They can thus reach impressive sizes. According to the Guinness World Records, the largest lobster was caught in Nova Scotia, Canada and weighed 20.14 kg (44.4 lb).
In general, lobsters move slowly by walking on the bottom of the sea floor. However, when they are in danger and need to flee, they swim backwards quickly by curling and uncurling their abdomen. A speed of 5 meters per second has been recorded.
Hermit Crab Facts
1) Hermit crabs return to the sea to deposit their eggs. Due to this they cannot be breed in captivity.
2) Hermit crabs drink by dipping their claws in water then lifting out drops of water to their gills and mouth.
3) On average we hear of hermit crabs living for a couple years as pets, however have heard of some that have been kept for over 20 years in captivity.
4) Hermit crabs love to climb. It is always a good idea to have a cage they can climb up or some other climbing material in their cage.
5) Hermit crabs are nocturnal. They move around a lot more at night then during the day
6) Hermit crabs have been heard making croaking sounds. It is still being studied to try to find out if this is a means of communication or what the croaking might mean.
