In this minute of relaxation, we invite you to look deep into the eyes of this beautiful creature and let it take you on a journey through time and space. Amphioctopus marginatus, also known as the “coconut octopus” and “veined octopus”, is a medium-sized cephalopod belonging to the genus Amphioctopus. Meeting any octopus is as close as we can currently get to an alien encounter. Their physiology is truly otherworldly!
Watch Coconut Octopus (Amphioctopus marginatus)
They have a large brain that extends into the nervous system of their arms! This means that its brain is not in 1 particular place, as with most other creatures, but has more of a “Multiverse” approach to brain function.
The body of the coconut octopus
Lacking skeletal support, this creature’s arms work as muscular hydrostats and contain longitudinal, transverse and circular muscles around a central axial nerve. This basically means that they can extend/contract their arms, twist left or right, bend at any place in any direction and/or be held rigid. Each arm has a multitude of muscle-controlled suction cups, that can grab, feel, manipulate, and even taste objects. Octopuses are basically “brains with arms”, or “thinking muscles”, that can control their bodies to such an extent, that they’ll fit through any opening the size of their beak. The parrot-like beak of all octopus species contains venomous saliva and is the only hard part of their bodies.
Masters of RNA
Octopuses, as well as some other cephalopods, are capable of greater RNA editing (which involves changes to the nucleic acid sequence of the primary transcript of RNA molecules) than any other organism. More than 60% of RNA transcripts for their brains are re-coded by editing, compared to less than 1% for that of a human. This allows the octopus to evolve/adapt/learn from the experiences of previous generations, without actually being taught.
Amphioctopus marginatus has 3 hearts for life
Octopuses have 3 hearts and depend on the copper-rich protein, haemocyanin, for oxygen transport throughout the body. Although in cold conditions and with low oxygen levels, haemocyanin transports oxygen more efficiently than haemoglobin, it also tends to make the blood thicker, resulting in blood pressures that can exceed 75 mmHg (10 kPa). But, with 3 hearts, the octopus isn’t really worried about high blood pressure. As an added bonus, the haemocyanin makes the octopus’s blood look blueish. True royalty!
The octopus and its coconut
Named for their use of coconuts as tools for defence, the coconut octopus can also use clamshells, or these days a variety of plastic rubbish, depending on their size. Although they have the ability to burrow and hide in the sand, they prefer the extra security these tools are giving them. Often the shells and husks that the coconut octopus gathers, will be used for dens or “defensive fortresses”.
Walk the walk
Coconut octopus (Amphioctopus marginatus) is even capable of bipedal (2-legged) movement and slit-walking, which allows them to carry the coconut or clamshells, with the remaining 6 arms. The octopus will carry a shell with it while searching for another, testing several as it scavenges as a hermit crab might. Coconut octopuses are commonly found throughout the tropical Pacific and the Indian Ocean. Their main body is normally around 8 centimetres (3”) tall and, including the arms, approximately 15 centimetres (6”) long.
What Amphioctopus marginatus eats
Their diet includes invertebrates such as shrimp, crabs and clams, although they will also eat small fish if they can catch them. With three to five years the coconut octopus has one of the longer life spans for octopuses. The primary contributing factor to determining their life span is when they decide to mate. The coconut octopus reaches sexual maturity between 18 and 24 months of age. Once a male mates he will die within weeks, sometimes days thereafter. The female will die only after she has laid her eggs and they have hatched.
How coconut octopus mates
The mating ritual of the coconut octopus is a “fast and furious” affair. Males prefer to insert their sperm packet with their specialized “sex arm” into the mantle of the female as quickly as possible. It has been observed in the wild that the females often strangle the males that hang around too long, and then eat them. Not quite the preferred dinner date… To avoid being eaten, male coconut octopuses employ the “mate and dash” technique. Some also disguise themselves as females in order to stand a chance while approaching.
Since the mating style of the coconut octopus is designed to be as fast and as distant as possible, there have been observations of a female octopus “entertaining” two or more male suitors at once. Yes, a saucy coconut octopus underwater orgy, so to say. Since the female carries the sperm packets in her mantle until she is ready to lay her eggs, having sperm packets from multiple males is not a problem. Consequently, the hatchlings that emerge from a specific brood can have multiple fathers. What a fascinating alien creature this octopus is!