If your favourite
animal isn’t the octopus I can tell you right now that you are wrong. These
majestic invertebrates are not only top predators but are also intelligent,
masters of camouflage and delicious. They are cephalopod molluscs with a beak,
2 developed eyes, 8 distinctive arms, venom, 3 hearts, and several
characteristics that belong in sci-fi films.
Firstly, I’d like to
settle the plurality debate: OCTOPUSES is the plural of octopus, not octopi.
This is because the name derived from ancient Greek (ὀκτώπους meaning 8 legs, obviously). Had octopuses been of
latin decent the “i” ending would be correct… but its not.
Camouflage
You
think chameleons are the masters of colour change? Wrong! Cephalopods
(octopuses, cuttlefish and squids) have the most advanced mechanisms of rapid
adaptive camouflage that cannot be matched by any land animal. Many animals
that possess the ability of colour change must move to the correct visual
background with appropriate lighting conditions to fully implement camouflage.
Octopuses however have such precise vision and sophisticated skin, they can use
direct neural control to rapidly change and fine-tune the optical diversity of
their colour change. As can be seen in the below image, the Octopus vulgaris can change from
completely invisible to its normal state in a fraction over 2 seconds.
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| A time lapse representation of the Octopus vulgaris using camouflage. The difference between the first and last image is 2.02 seconds. |
Not only are octopuses able to adapt their colour
they can also manipulate their shape. The ‘mimic octopus’ Macrotritopus defilippi has mastered the art of hiding in plain
sight. Often found in open sandy habitats, it mimics the swimming behaviour of
a flounder to deter predators. Typically, predators of the octopus are seeking
a soft, fleshy meal and will therefore ignore what seems to be a boney
flatfish. Octopuses have also been noted to use batesian mimicry whereby they
imitate the warning signals of a harmful species despite being harmless
themselves. Some species have been observed to imitate the colouration of the
deadly lionfish. Octopuses, and other cephalopods, are able to alter their
colour because of chromatophore organs. Chromatophore organs are composed of a
single chromatophore cell and an elastic sacculus containing pigment. When
excited, the sacculus can expand and retract accredited to specific neural control,
allowing particular colours/patterns to be revealed.
https://www.youtube.com/watch?v=orrdcwTuXmQ
DID YOU SEE THAT
DID YOU SEE THAT
There are even better videos on youtube but this was
the best I could find on short notice without annoying commentary. Have a look!
Intelligence
The
true extent of the octopuses’ intelligence is under serious debate but
regardless, their intellect can be considered a great evolutionary success. Two
thirds of an octopuses neurons reside in its arms rather than its head. This
means that each individual arm can “consciously” solve problems, like opening
shellfish, whilst the others can be busy doing other things like foraging for
more shellfish. It seems effortless that an octopus can coordinate and control
its 8 arms yet we as human beings struggle to control our own fingers….oh you
can? Try this: place your hand palm down on the table/floor/surface. Bend your
middle finger inward as shown in the picture. Now, keeping your hand down,
raise and lower your pointing finger….raise and lower your pinky….raise and
lower your thumb…raise and lower your ring finger. Not gonna happen. Also try
miming anticlockwise circles with your right foot whilst drawing the number 6
with your right hand.
 |
| Place your hand like so and see how much control you really have over your own digits. |
Back to octopuses
however…they are unique among invertebrates due to their extremely large
nervous system. In laboratory experiments they can readily learn to associate
visual or tactile stimuli with a positive or negative reward, they can learn by
observation and in maze experiments have shown prominent evidence of both a
short-term and long-term memory.
Like chimpanzees they
have also been witnessed to use tools. Some species of octopus carry coconut
shell halves under their bodies to later assemble into shelters; others use
stones to barricade the front of their dens. This shows a level of cognitive
ability and sophisticated behaviour that used to be exclusive to vertebrates.
Some octopuses have a special set of skills that even human beings cannot come
close to matching. For example, I can’t for the life of me win a football bet
yet a certain octopus named Paul managed to predict 11 out of 13 matches during
the 2010 world cup.
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| Paul the octopus |
Other amazing things about octopuses
that I can’t fit in without turning this into a novel
- The suckers on the octopus appendages are both incredibly strong and very delicate. Not only can they individually respond to subtle chemical signals, a single large sucker can hold up to 15kg.
- Their dexterity is phenominal. In some tests, octopuses have been able to unlock and open the top of a childproof pill bottle.
- The blue ringed octopus has enough venom to paralyse an adult (most species however, do not have venom)
- They can fit through the smallest of holes. As its body is fully flexible, an octopus can fit through any sized hole, no matter how small, as long as its beak can fit through. (http://video.nationalgeographic.com/video/octopus_cyanea_locomotion)
- They have 3 hearts – 2 work exclusively to transport blood beyond the animals gills whilst the 3rd acts similar to a human heart, circulating haemocyanin (equivalent of blood) to the organs. BONUS FACT – the heart actually stops beating as it swims which makes octopuses prone to crawling as swimming can be exhausting.
- Octopuses have highly developed eyes. Some species actually have colour vision and most have statocysts which allow the animal to sense its orientation relative to horizontal.
- The octopus defense mechanism of shooting ink at a potential threat does not only hide the animal, it also harms the predator. The ink contains tyrosinase which causes blinding irritation and disrupts the sense of smell and taste. Despite their advanced intelligence, octopuses that fail to escape their own ink cloud, can accidentally kill themselves.
- THEY CAN HUNT SHARKS. Seriously. Watch. (https://www.youtube.com/watch?v=rCDBt-4NSCk)
- Olfactory sensors have been identified in the suction cups on the octopuses arms. Meaning they can basically smell with their arms.
- A detached limb from a predation attack can regenerate. I have read that they occasionally eat their own arms in certain circumstances but the sources are far from reputable.
