Octopus ..... "the monsters of the deep"

Octopuses are ocean creatures that are most famous for having eight arms and bulbous heads. They squirt ink to deter predators; and being boneless, they can squeeze into (or out of) tight spaces. They are quite intelligent and have been observed using tools.

And sadly, for them, sex is a death sentence.. Male octopus typically dies a few months after mating. The female octopus also dies shortly after their eggs hatch. The duration of egg incubation normally takes 2 to 10 months,

However, there is a risk of the male octopus being eaten during mating due to the cannibal nature of the female octopus. To prevent this, they either mate in a distance, or the male octopus will mount onto the back of the female octopus, leaving time for his escape if things go wrong.

About an hour after the octopus has died, the octopus’ tentacles still have the ability to move and react. The tentacles can continue to pick food and place it on its mouth.
These soft-bodied octopuses are invertebrates –they don’t have bones. So their tentacles or “arms” are vulnerable to damage. The regrowth process will start as soon as they lose their tentacle or after it has been damaged. Most octopus species have suction cups on the bottom of each arm. The arms seem to have a mind of their own. In fact, 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.

Octopuses have an excellent sense of touch, according to the World Animal Foundation. Their suckers have receptors that enable an octopus to taste what it is touching.

A bulbous sack-like body, or mantle, is perched on top of an octopus' head. The only hard part of their bodies is a sharp, parrot-like beak that is on the underside, where the arms converge. Octopuses have powerful jaws and venomous saliva, according to National Geographic.

An octopus has three hearts. One pumps blood through its organs; the two others pump blood through its gills, according to the World Animal Foundation. Octopus blood is blue because it has a copper-based protein called hemocyanin.

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, giving the octopus time to swim away. 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. 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, according to the World Animal Foundation.

The oldest octopus fossil is from an animal that lived 296 million years ago millions of years before the dinosaurs lived.

sources:: facts.net/nature/animals/octopus-facts; live science.com/octopus