As Smart As Humans?
Did you know there are over 300 different species of squid that have been identified around the globe? However, it is believed that many more exist out there. They range considerably in size from species smaller than your fingernail to species bigger a London bus, and over 40 feet in length.
The heaviest squid ever caught alive was a Colossal squid ( Mesonychoteuthis hamiltoni) in 2007 around New Zealand. It was over 10 metres long and weighed more than 1,000 pounds!
The smallest contestant of the squid familiy is Idiosepius paradoxus, also known as the Northern Pygmy Squid which grows to around 16mm in mantle length!
Stories & Myths About Squid
Tales of giant squid have been common among mariners since ancient times, and may have led to the legend of the kraken, a tentacled sea monster as large as an island capable of sinking a ship.
Japetus Steenstrup, the describer of Architeuthis, suggested a giant squid was the species described as a sea monk to the Danish king Christian III circa 1550.
The Lusca of the Caribbean and Scylla in Greek mythology may also derive from giant squid sightings. Eyewitness accounts of other sea monsters like the sea serpent are also thought to be mistaken interpretations of giant squid.
Squids live in all sorts of water columns from the surface down to a depth deeper than 1,000 metres. Their usual habitat is our oceans but some of them do live in freshwater.
The Evolution Of Squids
The squid as we know it today has evolved from some of the earliest known molluscs on earth. The earliest known ancestor of today’s squid is “Kimberella” a tiny mollusc like a jellyfish which lived about 555 million years ago.
Squids Around Koh Tao
When diving Koh Tao you often can see Bigfin reef squids in little groups on the buoy lines when you descend. The best time to watch these fascinating but very shy critters from very close is during a night dive. If you find one and shine your torch towards it, they will be momentarily stunned and you can watch it. As soon as you shine your torch away from the Squid it swims off with a fast shot into the night.
Squid are also a delicacy in many seafood restaurants, especially so in Thailand. At night when you look out to sea, you can see green lights on the horizon. These are squid fisherman. They light up the waters around their boats to attract squids and catch them with their longlines!
Some curious facts about squid….
All Squids Have Three Hearts!
A median heart pumps oxygenated blood throughout the body, which it gets from two smaller hearts that pump blood through their gills.
A Giant Squid’s Brain Is Donut-Shaped
But that’s not the weird part. What’s truly bizarre is the fact that its esophagus passes through the hole in the middle of its brain. Giant squids have to be really careful while swallowing, because if a given meal isn’t broken down into small enough pieces first, it can rub against the brain and they become unconscious!
All Squid Species Have Beaks
These are incredibly hard, and are used to kill and tear their prey apart. Unlike the teeth and jaws of most other animals, these beaks contain no minerals whatsoever, and can even survive digestive juices. This is why squid beaks are often found inside whale stomachs when they’re opened up. Squid beaks are extremely hard to scratch or break, making them tougher and more resilient than all existing metals and polymers.
Squids Have The Largest Eyes In The Animal Kingdom
Compared to the size of its body, a squid’s eyes in general are very big. Giant squid, on the other hand, have the biggest eyes of any known animal in the world. A typical giant a squid eye measure up to 10.62 inches across, which is the size of a soccer ball.
Since giant squid live only in the deep ocean where there’s no light, these eyes also come with their own light organs, meaning they literally glow in the dark.
The Squid Heteroteuthis Dispar Can Shoot Light
One of the most well-known squid facts is that they shoot black ink at predators for defense. The heteroteuthis dispar, better known as the odd bobtail squid, and does it slightly different. Instead of ink, they produce bioluminescent mucous.
When threatened, they shoot out this light-producing snot, which blinds or confuses their predators. The result is a cloud of light that takes a while to dissipate, which is why this species is also called the fire shooter.
The Nocturnal Bobtail Squid Has A ‘Stealth’ Mode
They can control (dim and enhance) the brightness of the glow caused by the bioluminescent bacteria inside them to match the moonlight and therefore eliminate their shadow.
Multi-Tasking While Mating At Its Best
A male squid shows a friendly brown colour to attract females and an aggressive white to keep other males in distance. He would never show the white colour towards a female. So in the event of mating with a female he colourizes himself brown on the side towards the female and white on the outside as a warning for other males.
They Can Re-Grow Their Arms!
As soon as a squids arm is lost or damaged, a regrowth process kicks off to make the limb whole again—from the inner nerve bundles to the outer, flexible suckers. Once an arm is regrown, it is basically as good as new.
Squid Blood Is Blue, Not Red
Squid blood is copper-based not iron-based containing a copper-containing compound called haemocyanin. Therefore their blood is blue not red like ours.
As Smart As Humans?
The squids brain continues to increase in both, size and cell numbers, throughout its entire life. Some scientists believe that if squid where to live as long as humans they would develop similar intelligence to us.
Squids are my favourite critters around Koh Tao!
Author: Dirk Klickermann (PADI IDCS #310464)