Octopus

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Octopus
Octopus (blue)
Giant Pacific Octopus

While it is commonly and erroneously believed that chameleons change color to blend in with their environments, it is actually the octopus that has this astounding ability. It uses specialized muscles and pigment cells to duplicate almost any background. Although they can be formidable predators, even occasionally hunting sharks, the primary hunting or defensive techniques they use are hiding and camouflage, and they are masters at both. Their intellect is often compared to that of a parrot or even a five year old child, but there is no way of truly defining their intelligence.


Content List

1. Scientific & Common Names

2. Characteristics

a. Breeding

b. Behavior

3. History

4. Present Status

5. References


Scientific & Common Names

Kingdom - Animalia

Phylum - Mollusca

Class – Cephalopoda

Superorder - Octopodiformes

Order - Octopoda

Suborder – Cirrina and Incirrina

Common Names - Octopus


Characteristics

For an animal that is so intelligent and complex, they have shockingly short lifespans. The average lifespan is only 1-2 years while the giant Pacific octopus (Enteroctopus dofleini) has both the largest size and longest lifespan, weighing in at an average of 35 pounds and living to the ripe old age of 3-5 years. For many species of octopus, color is impossible to state since they change hue according to mood or need for camouflage, although they have a standard resting color. All octopuses have eight arms in sets of twos generally with powerful suction cups as well as they ability to quite literally think on their own. Octopuses have 500 million neurons, only half of which are found in their brains. The rest are distributed through their arms, allowing each appendage to act independently. When the arms are severed, they are able to continue to move and even hunt for a short period. They also have three hearts, all of which moves their blue tinged, copper rich blood throughout their system. Not all octopus are venomous, but some species, such as the blue ringed octopus – which is actually three or four separate species – can be deadly. The maculotoxin found in one Australian blue ringed octopus is enough to potentially kill ten adult humans.


Breeding

One of the male’s arms is specialized to deliver packets of sperm to the female’s mantle, where she can store it until her eggs are ready to be fertilized. She will then lay between 30,000 and 200,000 eggs, depending on the species and the individual octopus. The males die soon after mating and the females generally only live long enough to brood and protect the eggs. The females will sit with the eggs, never leaving even to feed, and move water over them and attempt to keep predators such as sunflower sea stars at bay until the eggs hatch, which can actually take up to a year, or as little as a few months, depending on the environment and species. Upon hatching, the larvae spend 1-3 months as plankton before the juveniles develop enough to swim into deeper water and begin rapidly growing.


Behavior

There are over three hundred species of octopus and they vary in size, coloration, shape, and behavior. They can swim slowly or use powerful jets to shoot themselves away from danger and many walk over the sea bottom using some or all of their arms as legs. Often, they can temporarily blind their predators with a cloud of ink, which consists primarily of mucus and melanin. With few exceptions, the only hard section of most octopus species is their beak, which allows them to squeeze through any opening large enough to pass the beak. Many species can seamlessly blend into their environment using both color and changes in their skin texture. The mimic octopus, Thaumoctopus mimicus, is able to contort its body into a wide variety of shapes so that it can impersonate anything from sea snakes to lionfish. Octopuses can move well on land for an aquatic species, but they must remain moist to survive.


History

Nearly half of the cephalopods alive today are octopus. The others are cuttlefish, nautilus, and squid and the cephalopods are considered to be the most highly evolved marine invertebrates. As they are soft bodied and rarely fossilize, there are less than a dozen known fossils of ancient octopus, although their cousins, the nautiloids, have an extensive fossil record. It is believed that early octopus began to evolve during the Late Devonian period (360ma) when they split with vampire squid, but the first fossils do not appear until closer to the Permian period (245-290ma).


Present status

Octopuses are not considered endangered at this time but some areas do have protections in place to ensure their continued survival. In Washington State, for example, there are strict rules concerning where and how giant Pacific octopus can be caught.


References

Octopus: Physiology and Behaviour of an Advanced Invertebrate by M. J. Wells

The Human, the Orchid, and the Octopus: Exploring and Conserving Our Natural World by Jacques Cousteau, Susan Schiefelbein

Octopus and Squid: The Soft Intelligence (The Undersea discoveries of Jacques-Yves Cousteau) by Jacques Yves Cousteau

Cephalopod Behaviour by Roger T. Hanlon, John B. Messenger

Octopus: The Ocean's Intelligent Invertebrate by Roland C. Anderson, Jennifer A. Mather