Which Mollusk Has Eight Tentacles? Octopus is a mollusk that has eight tentacles or arms surrounding a beak-like mouth. Octopuses’ are reckoned to be the world’s most intelligent invertebrates and are able to use tools with their sucker-covered tentacles.
Technically, octopuses don’t have any tentacles at all! Instead, they have arms. When you’re talking about cephalopods, tentacles tend to be much longer than arms and only have suckers at their “clubbed” ends, where arms are shorter, stronger and suckered all the way down. Tentacles also typically come in pairs. Squid and cuttlefish have eight arms plus a pair of feeding tentacles.
Another study suggests that two of the octopuses’ arms are mainly used as legs while the remaining six are employed for other important functions such as feeding. According to this study, octopuses have two legs and six arms. But our question remains. Whether we call them limbs, tentacles, arms, or legs, are they still always eight?
The Haliphron Atlanticus is a sizeable octopus species widely known as the seven-arm octopus. One might assume from the name of this octopus, which is to be found in the Pacific and Atlantic Oceans that it only has seven arms. The truth is that the male seven-arm octopus only appears to have seven arms. The eighth arm is used for reproduction and is coiled in a sac beneath its right eye. This is the reason the species have acquired this misleading name but in fact, even the seven-arm octopus is characterized by the existence of eight limbs. Now we know that Octopus is a mollusk that has eight tentacles or arms for sure.
The octopus has many dangerous enemies to face during its short lifetime. Dolphins, sharks, and eels are among the fiercest. Although octopuses have developed amazing defense mechanisms, sometimes during a fight it might need to sacrifice an arm or two to survive. Nevertheless, the sight of an octopus with less than eight arms is not so common as one might think thanks to its incredible regeneration ability. As soon as an octopus loses or damages an arm, the process of regrowing it is initiated and it is completed when the limb is made whole again, up to its last nerve and sucker. This process lasts for around 100 days and it is surely one of the main reasons why octopuses are such magical creatures.
Octopuses also have well – developed eyes and brains, but no shell. All octopuses are marine, feeding on other mollusks and crabs which they catch or envelop with their suckered tentacles. The shells are dealt with by the jaws, and the meat is scooped out by the tongue. Most octopuses are quite small. They normally stay hidden out of sight under stones or in crevices until it is time to feed or mate.
The blue-ringed octopus is an extremely venomous species living in Australian waters. The blue-ringed octopus, though tiny, packs a lethal punch. Despite being absolutely adorable, it is one of the deadliest animals in the world. The little cephalopod doesn’t have razor-sharp teeth or even the ability to travel particularly fast, but it does produce a paralyzing neurotoxin that can leave unsuspecting company paralyzed — or dead.
Characterized by its blue and black rings which appear when the animal feels threatened, the seemingly harmless mollusk possesses a venomous neurotoxin, known as tetrodotoxin, which it releases through its salivary glands. Technically, all octopuses and cuttlefish are venomous, but the blue-ringed octopus can’t be compared.
Tetrodotoxin is 1,000 times more deadly than cyanide and the amount of poisonous liquid the little cephalopod carries can mean certain death for up to 26 people, or leave someone paralyzed for up to 24 hours after the first contact. Worse yet, there is no known antidote. A victim’s best bet is to get respiratory help immediately.
Content for this question contributed by Jun Sison, resident of Quezon City, Philippines
