The Octopus
The Octopus
by Tim & Meg
by Tim & Meg
GENERAL CHARACTERISTICS
The octopus is one of the most well known deep sea creatures. They have a large head that actually contains their vital organs. They also have eight tentacle arms branching off, and resemble something you might see in a sci-fi movie. Each of these eight legs are mostly covered in suction disk appendages. Octopus are extremely intelligent, and possess a wide variety of techniques to subdue prey and escape predators. They grow up to 4.5 feet in length and weigh up to 22 pounds. They belong to the phylum Cephalopoda and subclass Coleoidia, which are invertebrates with some of the largest nervous systems among their kind.
Octopuses hunt during the night, where they have the advantage over other fish who cannot see well in the dark or sleep during the night. Octopuses can pursue their prey by "crawling" or jet propulsion, both very quick and effective. Octopuses use their dexterous tentacles equipped with suction cups to ensnare their prey, where they bite it with a sharp beak, sometimes injecting it with a immobilizing salivary gland toxin. They can ambush prey from behind concealed underwater structures or simply pick up immobile mollusks or crustaceans. Once an octopus has caught its prey, it generally will "taste" its catch before consuming it in its entirety. These creatures are extremely picky eaters. If they are not satisfied with the catch, they will not eat it, even if they are on the brink of starvation.
NATURAL DEFENSES
Octopuses utilize three main defense mechanisms.
- Skin coloring - on top of natural resting skin patterns, most octopuses can strategically change the color of their skin through special skin cells called chromatophores which alternate the pigments visible in the skin cells along with the opacity and intensity of light reflection. Through chromatophores octopuses can camouflage themselves or change their color to intimidate predators.
- Ink projection - octopuses contain a sac full of melanin-based ink that can be dispelled in a large cloud to mask their "getaway" from a predator. The ink cloud acts not only as a visual deterrent, but also temporarily weakens the predators sense of underwater smell.
- Autotomising limbs - as a last resort, an octopus can shed one or multiple tentacles at will, in order to escape a predator. This defense mechanism is similar to that witnessed with lizard tails on land.
HABITAT
Octopus are generally found in tropical and temperate climates within oceans specifically, there aren’t any found in freshwater. They can be found in many places in these ocean waters, including coasts, reefs, and deep ocean floors. They commonly make shelters in natural forming rock crevices to shelter and hide from predators. Their bodies are made of mostly muscle, so they can squeeze through very tight spaces, which allows even more freedom to choose nesting locations that other animals can’t reach. They can even scatter rocks around their nest to aid in hiding.
COGNITIVE ABILITIES
Octopus are known to be some of the most intelligent vertebrates in the entire ocean. Tests have shown that they possess both short and long term memory capabilities. Sadly, since their lifespan is rather short, they usually can’t learn a large sum of information before they die. Two-thirds of an octopus’s nervous system is located in its arms, which can perform on their own remarkably well. Octopus are known to be able to learn observationally and can be trained to distinguish between different patterns. Because of these proven abilities, there are laws on how much experimentation can be performed on them. This is usually not the case for invertebrates, but because of their high intelligence, more protections are afforded.
SOURCES
- http://www.octopusworlds.com/octopus-feeding/
- http://www.asnailsodyssey.com/LEARNABOUT/OCTOPUS/octoPrey.php
- http://www.newworldencyclopedia.org/entry/Octopus
- http://www.newworldencyclopedia.org/entry/Octopus
- http://justinlp6.weebly.com/habitat.html
- http://animals.nationalgeographic.com/animals/invertebrates/common-octopus/
- http://animals.mom.me/distinguishing-characteristics-octopuses-6003.html
- http://www.nature.com/nature/journal/v524/n7564/full/nature14668.html
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