Descends most often are with surprise encounters, almost always I ask the dive guide what to expect down there. The depths as always is unpredictable, few critters could just pop up in an uncanny way and it always fascinates me observing their ways. Recently while diving in Sarangani Bay, after an encounter with a turtle, blue ribbon eel and observing mounds of artificial reef and maneuvering with the tricky current I thought was enough and paid-off my long trip to the south. But few minutes before we had our safety stop, a pair of keen eyes from our DM noticed the brownish critter over a reef crevice. It’s large bulging eyes popping out from the hole, lurking and stationery, it never thought it can attract passers-by. Observing it closely I failed to take photos!
Watching an octopus in its natural habitat was interesting, our presence disturbed it, provoking to come out in its lair. Well, the octopus was courageous and stood its ground, it didn’t swim away quickly but stayed defensively and before it left shoot a cloud of black ink! It fled nonchalantly in front of us, such cool critter. With such cunning ways, no wonder it is considered the most intelligent among invertebrates.
Here are few interesting facts about the common octopus:
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Octopuses have three hearts. Two of the hearts work exclusively to move blood beyond the animal’s gills, while the third keeps circulation flowing for the organs. The organ heart actually stops beating when the octopus swims, explaining the species’ penchant for crawling rather than swimming, which exhausts them.
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Octopus arms have a mind of their own. Two-thirds of an octopus’ neurons reside in its arms, not its head. As a result, the arms can problem solve how to open a shellfish while their owners are busy doing something else, like checking out a cave for more edible goodies. The arms can even react after they’ve been completely severed. In one experiment, severed arms jerked away in pain when researchers pinched them.
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Octopuses have blue blood. To survive in the deep ocean, octopuses evolved a copper rather than iron-based blood called hemocyanin, which turns its blood blue. This copper base is more efficient at transporting oxygen then hemoglobin when water temperature is very low and not much oxygen is around. But this system also causes them to be extremely sensitive to changes in acidity. If the surrounding water’s pH dips too low, octopuses can’t circulate enough oxygen. As such, researchers worry about what will happen to the animals as a result of climate change-induced ocean acidification.
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Octopus ink doesn’t just hide the animal. The ink also physically harms enemies. It contains a compound called tyrosinase, which, in humans, helps to control the production of the natural pigment melanin. But when sprayed in a predator’s eyes, tyrosinase causes a blinding irritation. It also garbles creatures’ sense of smell and taste. The defensive concoction is so potent, in fact, that octopuses that do not escape their own ink cloud can die.
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After mating, it’s game over for octopuses. Mating and parenthood are brief affairs for octopuses, who die shortly after. The species practices external fertilization. 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 arm (researchers do not know why). Afterwards, males wander off to die. As for the females, they can lay up to 400,000 eggs, which they obsessively guard and tend to. Prioritizing their motherly duties, females stop eating. But she doesn’t starve to death–rather, when the eggs hatch, the female’s body turns on her. Her body undertakes a cascade of cellular suicide, starting from the optic glands and rippling outward through her tissues and organs until she dies.
Life in the Great Beyond 