When octopods reproduce, males use a specialized arm to put packets of sperm into the female's mantle cavity. Most can eject black ink clouds to help escape, and some can shed an arm in extreme danger. They use active camouflage and mimicry, controlled by their nervous system. Octopods are active and intelligent predators, with good eyesight and brains. At least four specimens of the veined octopus ( Amphioctopus marginatus) have been seen picking up discarded coconut shells, and then reassembling them to use as shelter. Octopods are the only invertebrate which have been definitely shown to use tools. This gives them protection not normally given to invertebrates. In the UK, cephalopods such as octopuses are regarded as honorary vertebrates under the Animals (Scientific Procedures) Act 1986. They have even boarded fishing boats and opened holds to get in and eat crabs. Mature males average about 50 pounds and females about 33 pounds. The largest of the 300+ species of octopods, the giant octopus Enteroctopus, is large indeed. Octopuses often break out of their aquaria and sometimes into others in search of food. They have been seen in what some have described as play: repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them. In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns. Some octopods, such as the mimic octopus, can move their arms in ways which copy the movements of other sea creatures. Their short lifespans limit the amount they can learn. Maze and problem-solving experiments have shown that they do have both short and long-term memory. The exact extent of their intelligence and learning capability is much debated among biologists. Octopods are highly intelligent, probably more so than any other invertebrate. If they feel scared, they may turn white.īehaviour Intelligence Īn octopus opening a container with a screw cap
When they become angry, they can become red. When they are relaxed, for example, they are a dull, grayish brown or orange-tinged colour. If they are not blending in with their surroundings, they can signal their feelings using colour. Some octopuses can use their chromatophores for more than camouflage. When a camera focuses on an object to take a picture, the lens moves back and forth until the image that the camera sees is in the right focus. However, an octopus does not have this problem. So, when we look somewhere, part of what is there is not actually perceived (the brain 'fills in' so we do not notice). A blind spot is a special place in the eyes that is not able to sense light. They have no protective outer shell like the nautilus, which is another type of cephalopod.Ī beak, similar in shape to a parrot's beak, is their only hard part.īecause of this, it is very easy for an octopus to squeeze through very narrow openings between rocks, for example squeezing through a hole as big as its eye. Unlike most other cephalopods, most octopods have only soft body with no internal skeleton. The term 'octopod' is correct for members of the order Octopoda in general. The term 'octopus' may be used to refer to those in the genus Octopus. Octopods make up over one-third of the total number of living cephalopods. There are about 300 octopod species, of which more than 100 are in the genus Octopus. All octopods are venomous, but only the small blue-ringed octopus is known to be deadly to humans. They live rather short lives.Īn octopus trails its eight arms behind it as it swims. For defense against predators, they hide, flee quickly, expel ink, or use colour-changing camouflage. Octopods inhabit many regions of the ocean, especially coral reefs. They are intelligent predators with a taste for crabs. Many stay in cracks between rocks or corals when they are not hunting. Octopods have no internal or external skeleton, allowing them to squeeze through tight places. They have a hard beak, with the mouth at the center point of the arms.
They have two, large eyes and eight limbs with suckers. The genus is quite typical of most octopods. Octopus is a genus of cephalopod mollusc in the order Octopoda.
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