These swivelling hooks are smaller than the hooks on the arms and have only a single main 'claw'. Each row of rotating hooks is flanked by a row of tiny, marginal suckers. The arm hooks are set in a double row in the middle of each arm, with the serrated suckers above and below them.
The arm hooks are set in fleshy, very muscular sheaths and are strongly attached to the arms. They probably help to hold and immobilise struggling prey as it is being killed and eaten. Most of the arm hooks have a strong main 'claw', with two smaller cusps closer to the hook's base. This makes them three-pointed and maximises their ability to hold and dig in. The base of each hook also has a complex structure that is set deep into the surrounding muscle. There are suckers on both the arms and tentacles of the colossal squid.
All squid have suckers and their number, type, and arrangement is unique for each species. Squid suckers have a calcareous inner structure.
In colossal squid these are sharply serrated and probably lethal to prey. Toothfish caught on longlines sometimes have circular marks where they have been damaged by colossal squid suckers. Tentacle club swivelling hook and arm sucker dissected out from the fleshy suckers, Octopus can be found from the deep sea to coastal tide pools, and from warm tropical seas to the frigid Arctic and Antarctic Oceans.
They can be huge, like the the Giant Pacific Octopus of the cold waters of the North Pacific, whose average 50 pound weight and 15 foot arm span dwarfs most other octopus.
The smallest, Octopus Wolfi, is barely 2. Octopus, in general, are masters of camouflage. They have the ability to change both the color and texture of their skin. Specialized cells called chromatophores expand and contract exposing different pigments within the skin. This can help octopus, and other cephalopods, blend in with nearly any background and communicate their feelings to friend and foe.
By contracting different muscles, octopus can also change the texture of their skin, hiding among rocks, boulders, seaweed, or corals with ease. Octopus have 3 hearts and 9 brains! There is one central brain, and then each arm has a rudimentary brain. At Birch Aquarium: Flamboyant Cuttlefish. Cuttlefish are both masters of disguise and communication. They are able to expertly flash colors and patters in psychedelically moving displays.
Cuttlefish, on average, have the largest brain-size to body-size ratio and these big brains might have something to do with their complex communication.
Their flat bodies and cuttlebones the oval, calcium-rich bone is porous helps cuttlefish hover along the seafloor as they look for small prey. Though cuttlefish may look cute and slow, they are expert predators.
When food like small fish or shrimp is within range, the cuttlefish points and aims its arms at the prey and shoots out its tentacles with lighting-fast speed.
Squid have long, fusiform torpedo-like body shapes, allowing them to zip through the water with ease. Using jet propulsion as well as two small fins at the top of their long mantle, squid are able to move forward and backward in the ocean with great speed and maneuverability. There are more than types of squid that can be found in oceans world-wide. Squid are an important commercial fishery world-wide. Most squid are fished at night when huge lights are shined on the surface of the ocean to draw the squid up from the depths.
The tentacles have suction cups on them and are used to hold onto prey. The tentacles also have taste sensors that let the octopus know if what it grabbed is worth eating.
The octopus' mouth is in the center of its tentacles. It has a sharp beak on its mouth that it uses to crack shells. Some species may also inject prey with a toxic substance. Because it has no shell, an octopus can squeeze into very small spaces.
Octopus live alone and, like the squid, some species can shoot ink and change colors. Squid and Octopus Squid mollusks like clams and oysters but they have no shells on the outside of their bodies!
Squid mollusks like clams and oysters but they have no shells on the outside of their bodies! LightHawk: Destination Conservation E.
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