Changes

Order: Sepiida (Cuttlefish)  

Order: Sepiida (Cuttlefish)  

The '''cuttlefish''' is a marine animal that has eight arms, two tentacles, and a soft body. It is a cephalopod: a fast-swimming, intelligent mollusk that can change its skin color and release ink into the water to confuse predators. The cuttlefish swims by using its fins and by shooting water from its body (a type of jet propulsion). The cuttlefish is nocturnal; it hunts during the night, and it hides and rests during the day. It has a life span of about 18 months.  

The '''cuttlefish''' is a [[marine]] [[animal]] that has eight arms, two [[tentacle]]s, and a soft body. It is a cephalopod: a fast-swimming, intelligent [[mollusk]] that can change its skin color and release ink into the water to confuse [[predator]]s. The cuttlefish swims by using its fins and by shooting water from its body (a type of [[jet propulsion]]). The cuttlefish is [[nocturnal]]; it hunts during the night, and it hides and rests during the day. It has a life span of about 18 months.  

==Anatomy==

==Anatomy==

===Arms and Tentacles===

===Arms and Tentacles===

Unlike the octopus's arms, which that animal often uses to move and carry objects, the cuttlefish's eight arms are specialized for grasping prey after the cuttlefish captures it with its two elongated tentacles. When potential food sources such as fish or shrimp swim near, the cuttlefish can alter the color of its skin while waving its arms in a mesmerizing display. This lures potential prey to within reach of the cuttlefish's tentacles, which can then shoot rapidly from a pocket at the base of the arms to grab the prey. The arms are also important for a defensive display in which the cuttlefish sucks water into its mantle cavity and spreads its arms in order to appear larger to its potential opponent.   

Unlike the [[octopus]]'s arms, which that animal often uses to move and carry objects, the cuttlefish's eight arms are specialized for grasping prey after the cuttlefish captures it with its two elongated tentacles. When potential food sources such as [[fish]] or [[shrimp]] swim near, the cuttlefish can alter the color of its skin while waving its arms in a mesmerizing display. This lures potential prey to within reach of the cuttlefish's tentacles, which can then shoot rapidly from a pocket at the base of the arms to grab the prey. The arms are also important for a defensive display in which the cuttlefish sucks water into its mantle cavity and spreads its arms in order to appear larger to its potential opponent.   

===Beak===

===Beak===

The cuttlefish's beak looks much like a parrot's beak, but it is hard to see because it lies buried at the base of the animal's eight arms. The cuttlefish can use its beak to help subdue prey and to defend itself against predators and rivals by biting. Like cuttlebones, beaks differ among species, and their remains enable scientists to identify which cuttlefish species have lived and died in certain areas.  

The cuttlefish's [[beak]] looks much like a [[parrot]]'s beak, but it is hard to see because it lies buried at the base of the animal's eight arms. The cuttlefish can use its beak to help subdue prey and to defend itself against predators and rivals by biting. Like cuttlebones, beaks differ among species, and their remains enable scientists to identify which cuttlefish species have lived and died in certain areas.  

===Brain===

===Brain===

The cuttlefish has one of the largest brain-to-body size ratios of any invertebrate, perhaps even larger than that of the octopus. The cuttlefish brain can handle input from a variety of senses, including sight, smell, and even "sound" (in the form of pressure waves). According to some scientists studying cephalopod learning, the cuttlefish can use visual clues to solve mazes, making it as intelligent as the octopus or land animals like the pigeon.   

The cuttlefish has one of the largest brain-to-body size ratios of any invertebrate, perhaps even larger than that of the octopus. The cuttlefish [[brain]] can handle input from a variety of senses, including [[sight]], [[smell]], and even "[[sound]]" (in the form of [[pressure wave]]s). According to some scientists studying cephalopod learning, the cuttlefish can use visual clues to solve [[maze]]s, making it as intelligent as the octopus or land animals like the [[pigeon]].   

===Cuttlebone===

===Cuttlebone===

A defining characteristic of the cuttlefish, the cuttlebone is a porous internal shell that helps control buoyancy, making it functionally similar to swim bladders in fish. Cuttlebones have both gas-filled forward chambers and water-filled rear chambers. Although it can take hours for the cuttlefish to change its density through its cuttlebone alone, the animal can control its positioning in the water with the aid of its specialized fins and mantle. The cuttlebone is rich in calcium and is often sold in pet stores as a nutritional supplement for birds.  

A defining characteristic of the cuttlefish, the cuttlebone is a porous internal [[shell]] that helps control [[buoyancy]], making it functionally similar to [[swim bladder]]s in fish. Cuttlebones have both gas-filled forward chambers and water-filled rear chambers. Although it can take hours for the cuttlefish to change its density through its cuttlebone alone, the animal can control its positioning in the water with the aid of its specialized fins and mantle. The cuttlebone is rich in [[calcium]] and is often sold in pet stores as a nutritional supplement for birds.  

===Eye===

===Eye===

Although color-blind, the cuttlefish has two of the most highly developed eyes in the animal kingdom. It can see well in low light and can also detect polarized light, enhancing its perception of contrast. While we humans reshape our lenses in order to focus on specific objects, the cuttlefish moves its lenses by reshaping its entire eye. Also, the cuttlefish's eyes are very large in proportion to its body and may increase image magnification upon the retina, while the distinct "W"-shaped pupil helps control the intensity of light entering the eye.  

Although [[color-blind]], the cuttlefish has two of the most highly developed eyes in the animal kingdom. It can see well in low light and can also detect [[polarized light]], enhancing its perception of [[contrast]]. While we humans reshape our lenses in order to focus on specific objects, the cuttlefish moves its lenses by reshaping its entire eye. Also, the cuttlefish's eyes are very large in proportion to its body and may increase image magnification upon the [[retina]], while the distinct "W"-shaped pupil helps control the intensity of light entering the eye.  

===Fin===

===Fin===