Table of Contents Coral Reef Cart Collection

GENERAL INFORMATION

Classification

• 
  Phylum Mollusca, Class Cephalopoda
  
• 
  The cuttlefish is a cephalopod along with the squid, octopus, and nautilus.
  

Distribution

• 
  Indo-Pacific, Europe, Africa.
  

Habitat

• 
  Shallow, tropical or temperate coastal waters
  

Appearance and Behavior

• 
  Cuttlefish may be 2 – 3 cm to 1 m in length. The cuttlefish has a head with eyes and other sensory organs, a sac-like body mass that encloses internal organs, a gill chamber, and 10 limbs. The cuttlefish has three hearts and copper-based blood. The brain is ring-like and the esophagus goes straight through the brain.
  
• 
  All 10 limbs extend from the head. Eight of the limbs are arms covered with suckers and two are tentacles with suckers only at the tip. The arms are always visible, but the tentacles, are usually retracted out of sight into special pouches in the head.
  
• 
  The mouth, located between the arms, has a parrot-like beak and a radula used to tear and rasp their food.
  
• 
  The cuttlefish has well-developed eyes with a lens. They see well in low light. The pupils of their eyes are shaped like a “w.” Cuttles locate their prey visually
  
• 
  The internal shell, called the cuttlebone is located just under the mantle and extends along the dorsal side of the body. It is many chambered, light, and calcareous. The chambers of the shell contain gas that compensates for the weight of the animal’s tissues, keeping the cuttlefish neutrally buoyant so that it neither sinks or floats and can move freely in the water.
  
• 
  Cuttles use fins for fine movement and jetting for gross movement. In order to jet, water is sucked in through the front of the mantle and expelled through the funnel, which can move and control the angle of spray and thereby the direction of travel.
  
• 
  Chromatophores in the skin are neurobiologically controlled. They produce five colors--yellow, orange, red, brown, and black. Leucophores are deeper in the skin and produce white color. Iridophores are responsible for iridescence. Cuttlefish can also change their skin texture.
  

Diet

• 
  Small mollusks, crabs, shrimp, and fish. When hunting for food, cuttlefish may wave their eight arms. This may be to distract prey or for triangulation. The two long tentacles then shoot out to capture the food.
  

Defensive Strategies

• 
  Cuttlefish can observe changes in their environment and then modify their skin color and texture instantly to confuse prey, escape predators, or communicate with other cuttles.
  
• 
  Males have been observed to have one side of their body show a dominant display toward other males, while the other side of the body shows a calm display towards a potential mate. They may use their chromatophores to create a “passing cloud” display on their bodies, perhaps as camouflage. They also produce ink that can be used to create a smokescreen or to produce a pseudomorph shape that may serve as a decoy.
  

Reproduction and Development

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  Cuttlefish mate face to face. The male uses the third arm on right to transfer sperm packet to female’s buccal area. Sometimes “sneaker” males will spray water to flush another male’s sperm out of the female and leave his own.
  
• 
  The female lays 50 – 100 eggs in a clutch. They inflate after they are laid. The female places them in a specific location and then wraps a sticky substance around them. She may come by and fan them from time to time. Ink is incorporated into the eggs for camouflage. As the eggs develop, they become more transparent.
  
• 
  Babies are called hatchlings.
  

Mortality/Longevity

• 
  Cuttles live for about a year. All go through senescence.
  

Remarks

• 
  Cuttlefish are intelligent and have been able to learn to navigate a simple maze.
  
• 
  Cephalopod intelligence is a topic of study for some scientists such as Jean Boal, an animal behaviorist, because cephalopods have such large brains compared to their relatives the clams and snails. Boal says that if we can figure out what they are using their intelligence for, that would tell us what the factors are in the environment that created the need for intelligence and that can shed some light on our own intelligence.
  
• 
  Cuttlefish are also interesting because they only live one year and scientists can use them to study how the ability of an organism to learn changes as it ages.
  

TO NOTICE

• 
  Notice the shape, size, weight, and porous nature of the cuttlebone.
  
• 
  Cuttlebones are commonly used as a calcium-rich dietary supplement for caged birds, hermit crabs, snails and turtles.
  
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  Compare the cuttlebone to the hard parts of other cephalopod cart specimens: the beak of the octopus and the shell of the nautilus.
  
• 
  Compare the photos of cuttlefish, octopus, and nautilus.
  

Chambered Nautilus

Specimen

nautilus shell sliced section

General information

Classification

• 
  Phylum Mollusca, Class Cepalopoda. Species: Nautilus pompilius (Nautilidae)
  
• 
  The nautilus is a cephalopod along with the cuttlefish, squid and octopus.
  

Distribution

• 
  Found in the tropical Indo-Pacific
  

Habitat

• 
  Usually found between 60 and 750 m on the slopes of coral reefs. In the daytime they will be at the lower depths and then rise to shallower waters each evening to feed on prey that also migrate upward.
  

Appearance and Behavior

• 
  The nautilus is the only cephalopod that has a fully developed shell for protection. A nautilus shell can be 20 to 27 cm across. The surface of a nautilus shell is lined with alternating wavy brown and white lines. The shell is produced by the mantle and is divided into compartments (about four in newly hatched specimens, 30 in mature individuals) and the animal occupies only the outermost “living chamber.” As the nautilus grows, its body moves forward in the enlarged shell and produces a wall to seal off older chambers.
  
• 
  The sealed chambers contain argon-nitrogen gas mixture and a liquid saline solution. The chambers are connected by a tube called a sipuncle that gives the nautilus the ability to change the ratio of a liquid to a gas which can modify its buoyancy. The nautilus moves in a see-saw motion using “jet propulsion” by alternately pulling water into the mantle cavity and forcing it out the flexible siphon beneath the tentacles. The direction the nautilus goes is controlled by the way the siphon is pointed.
  
• 
  There is a large leathery lid that can be lowered down to cover the shell opening. Normally, however, the lid is raised slightly and the animal’s eyes, tentacles, and siphon protrude.
  
• 
  The nautilus has 38 or more tentacles (and even up to 90). Instead of having suckers like the squid and octopus, nautilus tentacles are lined with alternating grooves and ridges that allow them to grip objects. Tentacles pass food into the mouth where a beak-like jaw tears it up and a file-like radula further shreds the food.
  
• 
  The nautilus has a very simple eye. The pupil of the nautilus eye is actually a hole and the water the nautilus lives in flows through the eye. Light strikes directly on the retina to create a blurred image.
  

Diet

• 
  Migrating to shallow waters each evening, the chambered nautilus is a predator and scavenger. It eats crab, shrimp, small fish, and carrion. Its prey are detected using chemical cues and vision.
  

Predators

• 
  The nautilus is eaten by the octopus, shark, triggerfish and sea turtle.
  

Reproduction and Development

• 
  The nautilus takes 5-10 years to reach sexual maturity. Males have a modified arm which functions to transfer a sperm packet. Fertilization occurs much later when the eggs are deposited. The female lays several eggs, one at a time. She uses her tentacles to attach each egg to a hard surface where it remains for 9-12 months before emerging as a hatchling.
  

Mortality/Longevity

• 
  The nautilus can live for up to 20 years.
  

Conservation Status

• 
  Collected for the shell trade. It is consumed in its range by humans. Not on IUCN Red List.
  

Remarks

• 
  The nautilus is considered by some scientists to be a living fossil since it is virtually unchanged in the last 500 million years. In prehistoric times there were about 10,000 different species of nautilus and they dominated the ancient seas before the rise of the fishes. Now there are only six species.
  
• 
  The nautilus eye is interesting because it is an intermediate step in the evolution of the advanced eyes of other cephalopods (octopuses, cuttlefish and squid) and humans. The most primitive eyes are just patches of light sensors on the outside of the skin that can detect light and dark, but not direction. Eyes with light sensors located in a cavity, however, can begin to detect direction. The next stage is the nautilus eye which can detect large shapes but no detail. The final step is the addition of a lens--something that has been done by other cephalopods and humans—to provide clear and detailed vision.
  

TO NOTICE

• 
  Compare the shell of a nautilus to the only hard part of other cephalopod cart specimens—the octopus beak and the cuttlebone.
  
• 
  In the sliced shell, notice where the outermost “living chamber” of the nautilus would be.
  
• 
  Notice the connections between the chambers.
  
• 
  Since its predators can be triggerfish, octopuses, and sharks, look at these cart specimens and see how they might be able to break or drill through the nautilus shell.
  
• 
  Notice the shell’s counter-shading—a form of camouflage coloration which makes it more difficult for predators to see. It is light on the bottom and dark on top. Fish can have counter-shading, as do our penguins.
  
• 
  Point out that this shell can withstand the pressure of the sea at depths of 800 m (over 2,600 feet).
  
• 
  Look at a photo of a live nautilus and see what parts are visible.
  
• 
  Look at a photo of the eye of the chambered nautilus and review the description of its structure and how it relates to other types of eyes.
  
• 
  Notice the cross-section of the shell is a particularly elegant looking spiral shape—a logarithmic spiral which is a mathematical function first studied by Sir Isaac Newton. The logarithmic spiral has the property of self-similarity: if you make it bigger or smaller, the new curve can be superimposed exactly on the original although you will need to turn it to get it to match. Some other spiral-shelled mollusks, including garden snails, have shells based on the logarithmic spiral, but the nautilus is a particularly striking example. The animal has such a shape because it continues to grow as long as there enough food. The bigger it gets, the more food it can catch, and the faster it grows, so the shell must grow accordingly.
  

Octopus

Specimens

octopus model

GENERAL INFORMATION

Classification

• 
  Phylum Mollusca, Class Cephalopoda
  

Distribution

• 
  Oceans worldwide
  

Habitat

• 
  Salt water: open ocean, shallow seas, ocean depths
  

Appearance and Behavior

• 
  Octopuses range in size from 2.5 cm to 9 m (tentacle span). The octopus is a cephalopod—a Greek word that means “head-foot,” but what looks like a large head is actually the baglike body. This body contains the internal organs and is covered with a muscular layer of tissue called the mantle.
  
• 
  The octopus does not have a shell. In fact the only hard part is the beak located at the mouth in the center of the arms. This means the octopus can squeeze into small places.
  
• 
  The octopus has eight arms with many suckers on each arm. The range of sucker sizes gives the octopus greater dexterity. Suction cups have chemoreceptors that enable them to “taste” what they are touching.
  
• 
  Octopuses are probably the most “intelligent” of invertebrates and have a complex nervous system—part of it localized in the brain and part in the system of neurons in the arms. Octopuses monitor their environment using two large and well-developed eyes that can form accurate images and detect slight movements. They are able to learn and perform complex tasks, such as twisting the cap off a jar to reach enclosed food. Captive animals have been known to leave their tank at night to feed in other tanks and then return home before morning.
  
• 
  The octopus usually only swims if threatened. It will inflate the mantle cavity with water and then expel it through its funnel causing it to move forward with the arms trailing behind. By moving the funnel, it can change direction. Usually, however, the octopus likes to crawl along rocks, coral and sandy bottoms.
  
• 
  It is a solitary dweller in caves or under rocks. Some carry a shell “home” with them.
  
• 
  The octopus can change color in less than a second by means of specialized cells such as chromatophores, iridophores and leucophores in the skin. The octopus uses color change as camouflage, but also changes color with shifts in activity and in need to communicate with other octopuses. In addition, with the aid of special muscles, octopuses can alter their skin texture to match the texture of an irregular background.
  
• 
  When threatened, the octopus can also squirt ink into the water before fleeing-—an action that confuses and obscures the vision of predators.
  

Diet

• 
  Crabs, fish, shellfish
  
• 
  Most octopuses hunt at night. It is thought they scout out promising feeding grounds by sight and then extend their sucker-studded arms to explore the area by touch. They then lunge at the prey and grab it with arms and suckers. Octopuses have several tools for penetrating shells. An organ called the salivary papilla is covered with small teeth which can bore through shells. The octopus can also use radula to drill into a shell. The octopus delivers salivary secretions to the drilled hole that further corrode the shell. In addition, saliva weakens the prey and detaches it from its shell. Octopuses use their hard beaks to break up food and then the radula scrapes up the juicy prey.
  
• 
  The shells are discarded—creating the “octopus’ garden.”
  

Predators

• 
  Sharks, large fish such as groupers, and eels
  

Reproduction and Development

• 
  There is no courtship behavior.
  
• 
  The male inserts his third arm (hectocotylus) into the female mantle to deposit spermatophores. (Sometimes the arm remains detached in the female.) The male dies shortly after mating.
  
• 
  The female may mate several times. The female lays thousands of eggs through her funnel. She hangs them in clusters from the ceiling of her cave. She tends the eggs and aerates them constantly by blowing water over them. At this time she does not eat and dies after the eggs hatch.
  
• 
  The juveniles spend weeks in the plankton and then settle on the bottom.
  

Mortality/Longevity

• 
  Octopuses have a relatively short life expectancy although some may live up to five years. Death follows reproduction.
  

Conservation Status

• 
  The octopus is sensitive to water pollution, and its populations in some areas may depend on limiting contaminants.
  
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  Octopuses are a source of food in Asian and Mediterranean cuisine and therefore subject to possible overfishing.
  

TO NOTICE

• 
  Notice the size and shape of the chitinous beak.
  
• 
  Use a model or photo to point out the location of the beak.
  
• 
  Review the way the octopus eats. See the section above entitled Diet.
  
• 
  Show the photo of the blue-ringed octopus and tell the story from the section below called In the Field with the Researchers.
  
• 
  Compare to other cephalopod specimens: the nautilus shell and the cuttlefish bone.
  

IN THE FIELD WITH THE RESEARCHERS

• 
  One of the most lethal venomous tropical sea creatures is the small (about 15 cm) blue-ringed octopus. It is found in Australia and the Indo-Pacific up to Japan. The bright blue rings become visible when the octopus is alarmed. It feeds on small crabs and shrimp. It has two kinds of venoms: one less toxic for prey, one very toxic for predators. The poison is in the saliva, and it is unclear whether it is expelled into the water or delivered with a bite.
  
• 
  The following is a quote from Terry Gosliner, the Academy’s malacologist (studies mollusks) whose specialty is nudibranchs, when he was diving in New Guinea:
  

“It was one of those dives. . . . first I saw a big shark on the south side of Magic Passage, then a stonefish and two scorpionfishes. I began to work up into the shallows, turning over slabs of coral rubble, looking for nudibranchs. . . . All of a sudden I felt a sensation along my bare arm. A five centimeter long blue-ringed octopus (the only lethally toxic octopus) had crawled up from the slab onto my arm. Anti-venom was available at the Madang Hospital about 45 minutes away by boat and car, but I would have had only 20 minutes to get there . . . there would have been no way. I shook my arm and gasped in relief as the octopus fell away. The best part was that I found a new species of nudibranch under that slab.”

Directory: 2008
2008 -> Exam 1 of Computer Networks (ice 1230) 2008 7
2008 -> Program description
2008 -> Curriculum Vitae Museok Song
2008 -> Word Wall Chants Use these as fun ways to practice word wall words at home!
2008 -> Rockettothesky
2008 -> "Unique " "dfo " "Glide " "Country" "Other" "Nations" "X. Affected" "Locations" "Rivers" "Began" "Ended" "Days" "Dead" "Displaced" "Damage usd." "Main cause" "Severity " "Affected sq km" "Magnitude m " "Notes and
2008 -> The environment in the news
2008 -> Virginia High School League Scholastic Bowl page 2007-08 District Competition Match #46
2008 -> Missouri State High School Activities Association Match #12 2007-08 Conference & Tournament Competitions page
2008 -> Louisiana state university health science center new orleans emergency medicine residency program policies to supplement lsuhsc house officer manual

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