Cephalopods are a type of mollusk which includes octopus, cuttlefish, and squid species. They, uniquely, have internal shells that support the animal’s soft body. They are invertebrates and do not have a spine or any bones. Instead of bones, they have a thick rod made of organic materials. The only hard part on these animals are their beaks. This is why cephalopods can fit through tiny holes because if their beaks can fit, then their whole body can!
The one and only cephalopod in the Maryland Coastal Bays is tinier than you might think. Measuring in at a colossal length of 5 inches, the Atlantic Brief Squid (Lolliguncula brevis) is the fastest invertebrate reaching top speeds of 25 mph! If you look closely enough, you will see their elongated white bodies with dark red-brown or yellow-brown spots. Their ability to change their appearance from ghostly white to colorful hues is due to a cool adaptation called leucophores, which are structural reflectors that produce whiteness in cephalopods. Leucophores really come in handy when hiding from predators, but also help males signal to potential mates come mating season! Cephalopods are color blind; they can only see in black and white, but some researchers say their uniquely shaped pupils help them detect color to mimic the color of their backgrounds! Squids also have three hearts! They have two hearts to pump blood to their gills and use oxygen. The third heart pumps blood to the rest of the body.
FUN FACT: Squid blood is blue, not red, like in humans, because it contains copper, not iron, which is present in our blood.
Much like the beachgoers, these squids travel in schools and love warm, shallow water. They prefer the saltier waters found in our Coastal Bays. Most squids are osmoconformers, a word which means the salinity (dissolved salt content) on the inside of their bodies matches the salinity of the sea water! Squids are particularly important in ecosystems because they act as “biological pumps”, transporting carbon and nutrients between marine ecosystems as they move across the oceans. The brief squid usually moves with their tentacles in a backstroke movement, but it can make a quick getaway from sneaky predators by contracting their muscular mantle, absorbing water, and then forcing it outwards into a funnel under their head in a swift motion. This motion is known as jetting. Another magic trick used to avoid predators is the classic ink cloud distraction which is often paired with jetting to create a disappearing act. Some predators of the squid are large marine animals like whales, dolphins and sea lions, bigger fish like salmon and tuna, and even sea birds.
You might be wondering what a 5-inch squid usually eats. Good question! Anything it can fit in its mouth such as bottom-dwelling crustaceans, small fish, and fish larvae. Some examples of its prey found in the Coastal Bays include striped killifish, grass shrimp, and sheepshead minnows. They are also known to be cannibalistic. Squids consume 30 percent of their body weight in a day, imagine that!
Researchers have made amazing discoveries in the cephalopod community! Squids and other invertebrates can feel emotions like pain, anger, fear, and happiness. Cephalopods have displayed intelligence in that they can count, recognize patterns, solve problems, and even communicate through different signals. Lastly, unlike humans, squids have an excellent memory that improves with age. They can even remember the entire experience of their favorite meal! Squids are so smart that they can even get bored and start making mischief! What fun!