#10. They can be quite dangerous When people think of dangerous sea creatures,
their minds automatically drift towards sharks, dolphins, snakes, and stingrays. However,
octopuses can be quite dangerous too. Octopuses do not have sharp teeth or stingers, sure.
But they can be quite venomous, bringing quick, painful death to their victims. All species
of octopuses are venomous, but only the infamous blue-ringed octopus has venom lethal enough to kill a
human.
Octopuses are preyed on by a wide variety of creatures. These include fishes, seabirds,
sea otters, pinnipeds, cetaceans, other octopuses, and humans. And so, to protect themselves
from predators, they have a variety of tactics and mechanisms. However, their venom, produced
by their salivary glands, is usually a last resort.
Octopus venom contains a toxin known as tetrodotoxin as well as other more common neurotransmitters
like histamine, tryptamine, octopamine, taurine, acetylcholine, and dopamine. This venom can
cause nausea, respiratory arrest, heart failure, paralysis, blindness, and death. Even though
bites are hardly noticeable, and death can take place in a matter of moments, victims
can be saved if artificial respiration comes in to save the lungs from paralysis.
#9. Octopuses die after mating Octopuses have a life cycle that best represents
the idea that the purpose of life is to reproduce. Both males and females die soon after mating,
birth, and brief periods of parenting. Octopuses are birthed by external fertilization. This
is a mode of reproduction that is facilitated by aqueous environments. The general principle
is that the male organism's sperm fertilizes the female organism's egg outside of the female's
body.
In spite of this general principle, octopuses have a special way of getting external fertilization
done. Multiple males either insert their spermatophores directly into a tubular funnel that the female
uses to breathe, or else literally hand her the sperm, which she always accepts with one
of her right arms. After this happens, male octopuses wander off to die. Females still
have to see birth and parenting through.
Female octopuses can lay up to 400,000 eggs. Prioritizing motherly duties, female octopuses
stop eating and fiercely protect and tend to the eggs. Once the eggs hatch, the female
octopus's demise begins. She doesn't quite starve to death. Instead, her body begins
a degenerative process. It starts from the optic glands and ripples outward through her
tissues and organs until she dies.
#8. Octopuses have blue blood The red coloration of human blood is due to
a special pigment known as hemoglobin. Hemoglobin is an iron-based protein that is proficient
at transporting oxygen through the bloodstream and towards essential tissues for metabolic
processes. Octopuses lack hemoglobin, and so they lack red-colored blood. Instead, they
possess an alternative pigment known as hemocyanin.
Hemocyanin is a copper-based pigment protein, differing from iron-based hemoglobin. It is
colorless when unoxygenated but turns blue once oxygen attaches, giving octopuses their blue-colored
blood. This copper base of hemocyanin is more efficient at transporting oxygen than hemoglobin
when the water temperature is very low and not much oxygen is around. But in spite of
this oxygen-carrying efficiency, there's a drawback that has to do with acidity.
Hemocyanin causes octopuses to be highly sensitive to acidity. As such, if the pH of the surrounding
water dips too low, hemocyanin breaks down, and octopuses can't circulate enough oxygen.
And so, they die by asphyxiation. This is a problem octopuses will hardly ever face
unless they are out of their natural environments. However, things like oil spillages and climate
change can cause their deaths in this manner.
#7. Octopuses have three hearts Most organisms, even those way larger than
octopuses, only have only one heart. Examples of such creatures include sperm whales, sharks,
and dolphins. However, octopuses, which average 33 pounds, about the weight of one cinder block
and have a length of 14 feet, about a third the length of a small bus, have three whole
hearts. Of course, those other creatures have large hearts which are scaled to their massive
sizes. But then, each of the octopuses' three hearts performs specialized functions.
Other mollusks like squids and clams have open circulatory systems. This means blood
is not closed off into arteries and veins and spreads throughout the entire body. However,
octopuses form the exception of this animal phylum. Their three hearts are linked to the
rest of their bodies by arteries, veins, and capillaries.
Two of the octopus hearts are branchial hearts, which pump blood through the gills for respiration
and gas exchange. The third octopus heart is the systemic heart, which receives the
blood that’s drawn from the gills and pumps that oxygenated blood to the body system.
The systemic heart actually stops beating when the octopus swims, explaining the species'
penchant for crawling rather than swimming. Swimming actually exhausts these creatures.
#6. Octopus brains are not localized In the animal kingdom, it's quite common for
creatures not to have localized brains. An example of such a creature is the cockroach,
which can survive for up to ten days without a head before dying out of hunger due to not
having a mouth. Octopuses are very much the same way. Although they have large heads with
tentacles attached, some of their brain matter extends into their tentacles.
In fact, two-thirds of an octopus's neurons reside inside its tentacles and not its head.
This gives the creatures several advantages. For one, because of the proximity between
their sensory organs and their brain, they have a quick reaction time. Another advantage
is that they have excellent multitasking abilities. Arms can perform relatively complex tasks
such as opening shellfish while the head does something else, such as looking out for danger.
Octopus arms can even maintain some functionality when severed from the body. In an experiment,
severed arms jerked away in pain when researchers pinched them. Like lizard tails, these severed
octopus arms could also help the creature escape danger. They are also capable of regeneration.
#5. Octopus Ink serves multiple purposes Of all the adaptations which octopuses have
to hunt and to escape predation, one of the most iconic is their ink. Octopus ink is
generated by a special gland and then stored in their ink sack, which is located close
to their digestive glands. Octopuses largely use their ink to escape from prey.
Before octopus ink escapes from the gland, it passes through a series of glands that
mix it with mucus, creating a thick, dark blob. This mucus matrix is essential as it
traps the ink within a cloud and prevents it from dissolving too easily.
The octopus ink can hamper predators in a variety of ways. For one, by clouding their
vision. The ink is quite thick and impossible for even the best pair of underwater eyes
to see through. The ink also hampers olfactory acuity, making the best pair of underwater
noses confused as to where these creatures escape to. And, finally, the ink itself sometimes
attacks the predators as it contains a chemical known as tyrosinase, which can cause irritation.
#4. Octopuses can build underwater cities Octopuses are some of the smartest known creatures.
Some of their feats of observed intelligence include the ability to open jars, the ability
to use rocks to defend themselves, the ability to make tools using coconuts and shells, the
ability to solve mazes, and the ability to mimic other sea creatures to fool both predators
and prey. Out of all these abilities, one of the most fascinating things they can do
is get together and build underwater cities.
In 2017, a team of marine biologists discovered a group of 15 gloomy octopuses off the coast
of Australia who, previously thought to be a solitary species, were living together
in a makeshift city they called Octlantis. These octopuses were exhibiting complex social
behaviors such as communication, using tools, and evicting each other from their dens.
These complex social structures allow octopuses to stand better chances of survival. In a
group, they can easily repel predators, find food, as well as take better care of their
young. In the often-ruthless marine environment, only species with adaptations like this may
be around several generations into the future.
#3. Octopuses are masters of disguise If the repertoire of octopus defensive tools
which we have discussed already isn't impressive enough, consider the fact that these creatures
are masters of disguise. They spend about forty percent of their time in their dens,
and then, once approached, they send out a tentacle to investigate. If they identify
that they are being hunted by prey, they have two different camouflage-related techniques
they can use.
Octopuses can change their skin color and texture in under a second. This is a large
contrast to chameleons, which require several minutes to achieve the same. Once approached
by prey, octopuses can resort to aposematism or warning coloration. This is when they change
their color to signal to predators that they are not worth eating. In the animal kingdom,
bright colors are usually associated with toxicity. And octopuses use this to their
advantage.
The other camouflage technique they use is deimatic behavior. This is when they alter their shape to make
themselves appear as something they are not. Sometimes, they make themselves appear like
coral.
#2. Octopus suckers are strong and sensitive Octopus tentacles are not smooth. Instead,
they are bumpy, covered with suckers. These suckers are very strong and sensitive. They
can hold up to 35 pounds of force, equivalent to the octopus's own weight. They can also
detect tiny chemical changes in the water.
An average adult octopus has about 240 suckers per arm. The suckers can usually be found
on the interior surface. The suckers can move individually, making pinching gestures. Being
adhesive, they allow the octopuses to grab onto objects or anchor themselves.
The sensitivity of these suckers extends beyond chemoreception. They can sense and respond
to light, allowing the octopus to move even when the head is obscured. Octopuses have
fish-like eyes which are on the tops of their heads. They have excellent vision, even better
than that of humans.
#1. Octopuses are an ancient species Octopuses being so intelligent starts to make
sense when you realize that the species has been around for about 300 million years.
This was before life had even begun to spread on Earth. They have had lots of time to evolve
and develop the basics of higher cognitive functions. This explains why they have so
many defensive adaptations and why they are capable of using tools and building cities.
Octopuses also require a lot of stimulation and are quite playful. They tend to interact
with humans quite easily. When their environment doesn't give them this stimulation, then octopuses
find a way to give it to themselves. They have been known to nibble their own tentacles
from time to time. Although, of course, the tentacles grow back.
Would you rather be attacked by a Stingray or Octopus, let us know in the comments section
below.