Giant Squid

There is, perhaps, no other creature in the deep sea as famous and as misunderstood as the giant squid. It has appeared in fictional movies and stories to the point where most people believe it doesn't exist. But rest assured, it is very real. The elusive giant squid, known to science as Architeuthis dux, is one of the world's largest animals. It is known to reach a length of up to 60 feet. It is one of the largest known invertebrates in the world and one of the largest creatures in the sea. Many believe that the terrible Kraken of ancient myth may have been based at least in part on this real life monster.

The giant squid is a mollusk and is member of the cephalopod class, which includes the octopus and other squids. Very little is known about these mysterious creatures because until recently, none had been seen alive in the wild. Most of what we know about them comes from the bodies of dead squid that have washed ashore or been pulled up in fishermen's nets. A breakthrough occurred in September of 2004 when researchers from Japan managed to photograph a live squid in the wild. In 2006, the same team was able to obtain the first ever video footage of a live giant squid. This and other recent evidence suggests that these creatures may be more plentiful than previously thought.

Like its other squid cousins, the giant squid's body is composed of a mantle, eight arms, and two longer tentacles. The mantle, or main body, of the squid is typically around six and a half feet (2 meters) in length. The arms and tentacles account for most of the animal's length. The inside surfaces of the arms and tentacles are lined with hundreds of suction cups, ranging in size from about one to two inches in diameter. Each suction cup is surrounded by sharp, serrated edges that help the squid hold on to its prey. The upper part of the mantle has two small fins that are used to help maneuver the animal in the water, although its main source of locomotion is jet propulsion. The squid can move through the water at high speeds by taking water into its mantle cavity and then expelling it with great force.

The giant squid has a complex nervous system and a highly developed brain. They are thought to be highly intelligent, and may be one of the smartest invertbrates in the ocean. Their eyes are the among largest in the world, second only to their larger cousin, the colossal squid. These giant eyes are actually the size of an average dinner plate, nearly one foot in diameter. Large eyes are an important adaptation that helps the squid locate food in the darkness of the deep ocean. The squid probably cannot see in color, but their specialized eyes are though to be finely tuned for distinguishing differences in light levels.

The giant squid is the second largest mollusc in the world and is also the second largest invertebrate. The colossal squid is the largest. The female giant squid is much larger than the male. Females average about 43 feet (13 meters) in length. The much smaller males are believed to grow to about 33 feet (10 meters). There have been claims of specimens of up to 66 feet (20 meters), but none have been officially documented.

Many researchers believe the giant squid to be a very aggressive animal. During World War II, stories from the survivors of sunken ships tell of shipmates being eaten by these creatures in the dark of night. There have even been reports of giant squid reaching out of the water and pulling men off small boats. None of these reports have been officially verified, but they do paint a picture of a powerful predator. The squid's eight long tentacles have strong suction cups, which they use to hold on to their prey. A sharp, powerful beak finishes off their helpless victim with eerie efficiency. They are thought to feed on deep sea fish and other species of squid. It is believed that they are solitary hunters, preferring to hunt alone in the dark waters of the deep ocean. As large and powerful as these creatures are, they are not at the top of the food chain. The giant squid has at least one natural enemy. It happens to be a favorite meal of the sperm whale. The squid are commonly found in the stomachs of dead whales. Many of these whales even bear scars from the squid's suction-cupped tentacles. The main defense mechanism of the squid is a dark, black ink, which can used to create a smoke screen. This ink can temporarily confuse predators, allowing the squid precious time to attempt their escape.

Very little is known about the reproductive behavior of the giant squid. It is believed that they reach maturity at the age of three years and that the males mature at a smaller size than the females. The females lay a large number of eggs. Juveniles have been observed in the surface waters off the coast of New Zealand. Several aquariums are attempting to capture and maintain juvenile specimens in an attempt to learn more about this mysterious creature.

Giant squid are found throughout all of the world's oceans. They are usually found at depths of between 1,000 feet (300 meters) and about 2,000 feet (600 meters), although there are documented reports of specimens found as deep as 3,800 feet (1175 meters). They are usually found near continental and island slopes from the North Atlantic Ocean near Newfoundland, Norway, and the British Isles, and the South Atlantic near Southern Africa. They are also found in the North Pacific Ocean near Japan, and the Southwestern Pacific near Australia and New Zealand. Giant Squid are rare in polar and tropical regions.

From: http://www.seasky.org/deep-sea/giant-squid.html

Giant Isopod

Looking like it just crawled out of a bad science fiction movie, the giant isopod is without a doubt one of the strangest creatures found in the deep sea. Known scientifically as Bathynomus giganteus, it is one of about nine members of the genus Bathynomus. It is also the largest known members of the isopod family, a group of crustaceans closely related to shrimps and crabs. The giant isopod is also related to the small pillbugs that you can find in the garden. In fact, this insect-like creature is sometimes referred to as the giant pillbug. Giant isopods are not usually fished commercially, although some can be found in the occasional oceanside restaurant in northern Taiwan, where they are boiled and served with rice.

The enormous size of the giant isopod is a result of a phenomenon known as deep sea gigantism. This is the tendency of deep sea crustaceans and other animals to grow to a much larger size than similar species in shallower waters. Other examples of this would be the giant squid and the giant tube worm. The giant squid grows to a length of up to 60 feet in the deep sea. In comparison, its shallow water cousins only grow to about two feet in length. The reason for these size differences remains a mystery, although some researchers believe it may be an adaptation to help the animal deal with the enormous pressures.

The giant isopod can grow to a length of over 16 inches, which makes it one of the largest members of the crustacean family. Like its terrestrial cousin, the pillbug, the giant isopod's body is protected by a hard shell that is divided into segments. This allows it to be strong and flexible at the same time. When threatened, this animal can roll itself into a ball to protect its vulnerable underside. And just like its land-based counterpart, the isopod has compound eyes, with over 4,000 individual facets. This gives the animal a large field of view, and makes it extremely sensitive to fast movements. Because light is extremely faint in the deep sea, the giant isopod has developed large antennae to help it feel its way around as it crawls along the ocean floor.

The giant isopod is a carnivorous crustacean that spends its time scavenging the deep sea floor. Food is extremely scarce at these great depths, so the isopod has adapted to eat what ever happens to fall from above. This includes the bodies of dead whales, fish, and squid. It is believed that the isopod will also feed on some slow-moving animals such as sea cucumbers and sponges. The giant isopod has a complex mouth that with many components that work together to pierce, shred, and disembowel their prey. The isopod can go for long periods of time without eating and has been known to survive over eight weeks without food in when kept in captivity.

Giant isopods reproduce by laying eggs. These eggs are thought to be the largest of all the marine invertebrates. The females develop a pouch known as a marsupium, where the eggs are stored until the young are ready to emerge. When this happens, the young isopods escape from the marsupium as fully formed miniatures of the adults. At this stage, they are known as manca and are nearly fully developed. Bypassing the larval stage greatly enhances the young isopod's chances of survival.

Giant isopods are found in most oceans of the world. Their habitat ranges in depth from the dimly lit sublittoral zone at 550 ft (170 m) to the pitch darkness of the bathypelagic zone at 7,020 ft (2,140 m). They prefer mud or clay ocean bottom areas where they prefer to live solitary lives.

From: http://www.seasky.org/deep-sea/giant-isopod.html

Firefly Squid

Of all the bioluminescent life forms in the deep sea, there is one tiny creature who's light show puts all others to shame. This is the firefly squid, sometimes called the sparkling enope squid. Known to science as Watasenia scintillans, it is referred to in Japan as "hotaru-ika". It is a member of the cephalopod family and is related to many other squid species throughout the world's oceans. The firefly squid gets its name from the flashing lights that resemble those of a firefly. This squid is famous for the incredible light show that occurs each year off the coast of Japan as millions of these tiny animals gather to spawn.

The firefly squid is a small member of the squid family, growing to a length of only three inches (seven centimeters). The squid is equipped with special light-producing organs called photophores. These photophores are found on many parts of the squid's body and emit a deep blue light. Large photophores can be found on the tips of the tentacles as well as around the eyes. Thousands of tiny photophores can be found throughout the squid's body, giving it the ability to emit light along its entire form. The lights can be flashed in unison or alternated in an endless number of animated patterns. These light shows are thought to serve several functions. They can be used to communicate with potential mates or rivals. They may also be used to disguise the squid's shape and confuse predators, allowing it to escape. The firefly squid is the only member of the squid family that is believed to have color vision. While most cephalopods have only one visual pigment, firefly squid have three. They also have a double-layered retina in the back of the eye. These adaptations for color vision may have evolved to enable firefly squid to distinguish between ambient light and bioluminescence, and to help them decode the patterns of light created by other members of the species.

The firefly squid is an active predator. It is believed that the squid can use their blue lights to attract prey. By flashing the lights on and off, they can attract small fish and then pounce on them with their powerful tentacles. Firefly squid spend their days at depths of about 1,200 feet (365 meters). At night, they migrate up to the surface to search for food before returning the the darkness below.

The spawning season of the firefly squid runs from March to May. During this time, the squid can be seen gathering in large numbers in Toyama Bay in Japan. They gather here by the millions, and sometimes by the billions, to lay their eggs. Once the eggs have been released into the water and fertilized, the adult squid begin to die. This completes the one-year life cycle of the squid. This annual light show is so spectacular that the area where they gather has been designated as a special natural monument. Toyama Bay lies above a deep, v-shaped canyon in which the sea floor drops away suddenly. The flow of the ocean currents usually wells up from the bottom of this canyon and pushes the squid to the surface. Occasionally the squid can be found washed up on the shore in large numbers during a phenomenon referred to by locals as "squid drowning themselves". This event can cover the shoreline for miles, bathing the beaches in an erie blue glow.

Firefly squid are found throughout the western Pacific Ocean where they can typically be found at depths ranging from 600 to 1,200 feet (182 to 365 meters). This squid is considered a delicacy in Japan and is widely fished there during the spawning season. As fishing boats haul in their catches, the sea surface begins to glow a bright cobalt blue. The spectacle is so amazing that tourists travel with sight seeing boats just to watch the show.

From: http://www.seasky.org/deep-sea/firefly-squid.html