Tag Archives: Exoskeleton

The California Spiny Lobster

The California spiny lobster is a unique invertebrate (species lacking a backbone) that is found off the coast of southern California. This type of lobster belongs to a group of invertebrates known as Arthropoda. Arthropoda’s characteristics consist of having a segmented body, exoskeleton, and jointed appendages. These lobsters share the same grouping classification as insects and spiders! How cool is that!

California Spiny Lobster

A California spiny lobster hiding in its den.

The California spiny lobster lacks claws, unlike its friend, the American lobster, which can be found off the eastern coast. They are also reddish-brown in color and have an enlarged pair of antennae, used for sensing their environment. These antennae can also produce a loud clicking noise to warn off predators. California spiny lobster get their name from the forward-pointing spines that cover their bodies to help protect them from predators.

California Spiny Lobster tim

Credit: Tim S

Their hard shell, or exoskeleton, also helps to protect them from predators, but can make growing a challenge. To grow, the lobster must shed their shell to increase their size! This process is called molting. To do this the lobster must reduce the size of their body in the shell, by drawing in as much water as they can, so their shell isn’t too tight. Then, the shell breaks between the tail and their body (otherwise known as a carapace). The lobster will then flex their body back and forth and eventually back out of their old shell. During this period, the lobster is shell-less, and EXTREMELY vulnerable. They must stay hidden because it’s super hard to protect themselves from prey without their hard exoskeleton protecting them. The lobster will then start the process of growing a new shell, which can take several months.

California Spiny Lobster 2

CIMI snorkelers discover a discarded lobster molt in the water!

When it comes to movement in the water, these guys are experts! With ten legs, these lobsters can walk along the sea floor, as well as move backwards and even sideways! However, if they need to move fast from predators, they can tuck their tails under their abdomens and rapidly propel themselves backwards, similar to how octopus and squid move!

These animals are nocturnal, and spend most of their day hiding in rocky crevices. At night, they leave their dens in search of a meal. Their diet ranges from algae and dead organisms to snails, sea urchins, and clams. They have even been known for cannibalism in desperate times, and have been seen feasting on injured or recently molted lobsters!

Whether you see lobsters as an interesting sea creature or a delectable meal, next time you’re at your local supermarket or on a snorkel, be sure to check out everything these amazing creatures have to offer!

California Spiny Lobster hair

Lobsters make great head masseuses and hair stylists, when they’re not busy using their ten legs for scuttling about. Credit: Gabrielle R and Capri L

P.S. For some inspiration from a rabbi on growing through adversity and learning from lobster, click here: http://www.stillworks.org/blog/2016/2/27/how-to-grow-through-stress-lessons-from-a-lobster-by-a-rabbi

Written By: Brooke Fox

References:

https://dtmag.com/thelibrary/spiny-slipper-regal-and-rock-the-secret-lives-of-lobsters/

https://myfwc.com/research/saltwater/crustaceans/lobster/facts/

https://www.followyourfish.com/creature-feature-1/

https://www.lobsters.org/ticbio/biology3.html

 

Sheep Crab

sheep-crab-2It may be called a sheep crab but it looks nothing like a sheep and it sure doesn’t make a sound like a sheep. So, why are they called sheep crabs? It is reported that the name “sheep” comes from the wool-like algae that covers their exoskeleton.
As juveniles they use barnacles, bryozoans, hydroids, and algae as camouflage by decorating their carapace to protect themselves from predators. However, as adults they no longer do this because they are large enough to protect themselves from predators. The alga that grows on the adult carapace is known as an epibiont, an organism that lives on the surface of another living organism.

Decorator crab.

Decorator crab.

Their scientific name is Loxorhynchus grandis and they can be found as far north as Pt. Reyes, California to Baja California. You can see them if you went snorkeling or while scuba diving, their range in the water is from 20 ft to 500 ft of depth.

During the winter they like to spend their time in deep waters. But when the spring rolls around, both females and males travel to shallower waters to mate. The females carry a brood on their underside in the abdomen. The brood can be as low as 150,000 eggs or as much as 500,000 eggs.

Some species of crabs have the ability to molt their entire lives, they can shed their exoskeleton when they need to grow. The sheep crab can only do this up to a certain point. Once a sheep crab reaches maturity they have a terminal molt. After this final molt they are no longer able to increase in size or generate a limb if it is lost.

sheep-crab-1

Molting its a Process!

Throughout your childhood, do you ever remember growing out of your clothes or shoes from the previous year? Many marine organisms grow out of their “clothes” too, but instead of going shopping and buying new ones, they are capable of shedding their old outer layers and growing it back to fit.

Animals like crabs and lobsters have hard outer shells that are called exoskeletons. As they grow, these crustaceans need to get rid of their exoskeleton that is too small and grow a new protective layer that is a bigger size. This process is called molting and it happens at different times of the year for different animals. California spiny lobsters usually molt only once a year during the autumn, while crabs molt a few times a year in their early stages and then less often as they age.

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Photo Credit: http://www.aquariumofpacific.org

The California spiny lobster is pictured above. Notice the species does not have front claws for defense against predators, but they have spines on their exoskeleton instead.

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This is the tail molt of a California spiny lobster.

After the molting process, the shell of the crustaceans are soft and do not fully harden until a few days later. The soft shell leaves the animal exposed to the harsh elements in its environment and defenseless against predators. Molting is not only for shedding a small shell, but also for getting rid of shells that may be damaged or teeming with bacteria and harmful parasites.

Written By: Kenzie Richards

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