The image conjured when someone says “octopus” might be that of an eight-legged monster squeezing his prey tightly under the water. But they are actually very shy invertebrates! And tend to capture the imagination of divers and snorkelers alike.
Many octopus species have suction cups on the bottom of each arm and the arms seem to have a mind of their own. Two-thirds of an octopus’ neurons are in its arms rather than its head! That means that an octopus can focus on exploring a cave for food with one arm while another arm tries to crack open a shellfish. You will often see the arms acting independently, as most times the suction cups have receptors that allow the octopus to taste what it is exploring.
When encountering an octopus on a dive, you’ll often be left wondering just how smart they are. Many times they’ll sit and observe you just as you observe them. Interacting, utilizing tools and items around them, and exploring camera gear/supplies that come too close to their den. Curious and intelligent, and octopus is a wonder to see underwater.
Facts about the Octopus
A sack-like body, or mantle, is perched on top of an octopus’ head. Most have no internal skeletons or protective shells. Their bodies are soft, enabling them to squeeze into small cracks and crevices. The only hard part of their bodies is a sharp beak that is on the underside, where the arms meet. You will often see them “ink” when agitated to escape, and are masters of the art.
Octopuses come in many different sizes. The common octopus (Octopus vulgaris) is 12 to 36 inches long and weighs 6.6 to 22 lbs. The giant Pacific octopus (Enteroctopus dofleini) is the largest octopus. They typically grow to 16 feet long and weight around 110 lbs, but one was recorded to weigh more than 600 lbs. and measure 30 feet across, according to National Geographic. The smallest octopus is the Octopus wolfi. It is smaller than an inch long and weighs less than a gram!
Habitat and Habits
Octopuses live in oceans all over the world. Most are pelagic, meaning they live near the water’s surface in shells, reefs and crevices. Some species live on the floor of the ocean, making their homes out of caves. They tend to be solitary, though they do interact with other octopuses at times. When scared, octopuses will shoot a dark liquid, sometimes called ink, at the thing that scared them. This will temporarily blind and confuse a potential attacker. The ink can also dull the attacker’s smelling and tasting abilities, according to the Smithsonian article.
Octopuses can also change color to hide and match their surroundings. Masters of camouflage, you will swim by them without even knowing! They can turn blue, gray, pink, brown or green. The mimic octopus can also flex its body to resemble more dangerous animals, such as eels and lionfish. And if they get caught? Not a problem. Octopuses are well known for being able to survive an attack by sacrificing/losing their arms. Some have even survived with half their arms/body missing! Talk about a resilient animal.
Octopuses are carnivores. Meals can include clams, shrimp, lobsters, fish, sharks and even birds. Octopuses typically drop down on their prey, envelop it with their arms and pull the animal into their mouth where their strong beak takes over.
Octopuses have short life spans. Some species only live for around six months. Other species, like the North Pacific giant octopus can live as long as five years. Typically, the larger the octopus, the longer it lives–But sex is deadly for them. No matter what, when octopuses mate, they die soon after. During reproduction, a male delivers sperm by inserting a specialized arm (usually the third right arm) into the female’s mantle cavity.
Females usually lay 200,000 to 400,000 eggs, though it varies depending on species. She obsessively guards the eggs until they hatch. She even stops eating. After the eggs hatch, her body turns on her, according to the Smithsonian article. It goes through cellular suicide, which rips through her tissues and organs until she dies. Meanwhile, the male has swum away and dies in a few months.
When they hatch, baby octopuses are called larvae. They drift in plankton clouds and eat other animal larvae until they mature. As part of the plankton cloud, they are also in danger of being eaten by plankton eaters and so they must hone their camo skills and evasion.