When you first glance the humble octopus while diving, it seems interesting but does not have the wow factor that some other species have. It is neither big or graceful like a whale shark or a manta, nor is it as hyper colorful and cute as an ornate ghost pipefish or a nudibranch. However, dismiss the humble octopus at your peril; for as you’ll see this is a creature of abundant charm, intelligence and adaptability. Had it not been an invertebrate unable to support its weight out of the water, the octopus could have been one of the earth’s leading animals, colonizing every environment on earth.
The octopus is part of the phylum Mollusca, which is the largest marine phylum, comprising nearly 23% of all marine life. Within the phylum Mollusca, the Octopus is part of the class Cephalopod and the family Octopod (meaning eight legged). Of all the invertebrates on the planet, the Octopus is considered to be the most highly evolved and the most intelligent by a long way. So far, over three hundred species of octopuses have been identified worldwide, living everywhere in the ocean, from polar regions to the tropics, and inhabiting every depth from the surface of the sea down to several kilometers deep. Octopuses come in a variety of shapes and sizes from the size of a tennis ball to the enormous Pacific giant octopus, with an arm span of 4.3 meters.
Octopuses are some of the most dedicated parents in the animal kingdom; with a life span of around one to two years, they live to mate only once. Most males die shortly after mating, while females will lay their eggs and fan them with their tentacles to keep them oxygenated until they hatch. As a result of this dedication, the hapless mother usually dies of starvation shortly after her eggs have hatched. Now that is a dedicated parent.
Your average octopus has some of the coolest evolved biology in the animal world. Belaying their royal status as the smartest of all invertebrates, they actually have blue blood. In a similar manner to having eight legs – since obviously two or four are not good enough for our humble octopus – one heart is also not good enough, and octopuses are the proud owner of three functioning hearts. If all that was still not good enough, your average run of the mill octopus has an incredibly complex nervous system with one central brain and each tentacle endowed with its own separate system capable of independent actions. This system literally helps the octopus to avoid tripping over its own tentacles and getting entangled, and this cool feature also comes in handy when coordinating complex tasks and movements. The body of an octopus is completely soft, and the only solid part of its body is the beak, located in the center of its head, where all the tentacles join the body. This unique feature means that the octopus is the ultimate escapologist – it can squeeze its entire body through any hole that their beak will fit through.
Octopuses pack enough weaponry to make a NATO general’s mouth water – they have a vast array of weapons, both defensive and offensive, to help them get by. Firstly, all octopuses are venomous to their prey, although only one species is known to be venomous to man. Secondly, they can generate their own smoke screen by squirting a dark ink into the water to reduce visibility and allow the eight legged escape artist a chance to make a run for it. Not only does this ink smokescreen reduce the visibility of water, but it also contains chemicals that target a predators sense of smell, rendering it useless and thus allowing the lucky octopus to escape. Thirdly, the enterprising octopus can use its tentacles for a type of jet propulsion which gives it very rapid movement and acceleration underwater. All in all, it’s a wonder any predators ever mange to catch a plucky octopus.
When it comes to camouflage, the octopus has set the bar very high indeed. The skin of the octopus contains cells called chromatophores and iridiophores. Thanks to these amazing cells, not only can the octopus change its colors to instantly match its background, but it can also change the opacity and reflectiveness of its skin, as well as use bioluminesce to help fool predators and prey alike. Not only does the octopus change its skin color, but it also uses muscles to change the texture of its skin to perfectly match its surroundings. When it comes to camouflage in the animal world, truly the octopus has no rivals.