The Centre for Fortean Zoology was founded in the UK in 1992 - nearly 20 years ago. Over the past two decades it has expanded to become a truly global organisation. We opened our American office in 2001, our Australian office in 2009, and now - in our 19th year - we are proud to welcome CFZ Canada to the CFZ global family.

Tuesday, 2 April 2013

One Big Tentacled Family

“Sea Monsters” have long been a part of Atlantic lore and study.  When the Giant Squid was documented, it became pretty clear that this was the infamous “Kraken” that had been feared by many.  The largest giant squid ever recorded by scientists was almost 43 feet (13 meters) long, and may have weighed nearly a ton.  It might seem that something so large would be hard to miss, but since they live deep underwater they are rarely seen.  Sometimes the dead carcasses float to the surface or wash up on a beach and that gives scientists a good specimen to work with.

In 2012, The Discovery Channel was able to catch a live Giant Squid on an undersea camera.  While most research is done off New Zealand, this footage was captured off Japan.  Giant Squids were first recorded live in 2006, after researchers suspended bait beneath a research vessel off the Ogasawara Islands (Japan) to try and hook a giant squid. While filming, the research team from Japan's National Science Museum pulled a 24-foot (7-meter) squid to the surface.  The more recent footage is from the same area, and was captured deep within the squid’s natural habitat, a first for researchers

The longest Giant Squid mantle length on record is 7.4 feet (2.25 meters) and the length from the tip of the top fin to the end of the arms seldom is more than 16 feet (5 meters).  The longest total length (including tentacles) of a squid on record is 43 feet (13 meters).  This is far smaller than the 20 meter length rumored.  One of the explanations of this is that when the squids die and wash ashore, they are often quite bloated and worn from other species attacking them or feeding on them.  Exaggerations arise from sightings of life ones as well, as running across one of these monsters in open sea can be a frightening experience.  The eye of this squid can be as large as a beach ball.

Some researchers think there are as many as 8 species in the genus Architeuthis, each a different kind of giant squid. Other researchers think there is just one Architeuthis species, or Giant Squid.  Few specimens are available for study.   However, there are an estimated 500 species of squid overall, some only about an inch long and others (The Colossal Squid, Mesonychoteuthis hamiltoni), which can grow to 45 feet (14 meters).

An international team headed by Danish researchers tested DNA samples from 43 giant squid from around the world and were stunned to find that there is likely just a single species of the massive cephalopod.  The genetic diversity among the samples was lower than in almost any species ever reported, said Tom Gilbert, a researcher from the Natural History Museum of Denmark at the University of Copenhagen.

“That lack of diversity and no population structure is just crazy. We just cannot explain it easily once you start thinking that this is an animal that lives everywhere,” Gilbert said in an interview.
Giant Squids are closely related to snails, clams, and even slugs.  Cephalopods have been around for 500 million years.  Cephalopods are defined not by whether they have a shell, but by their soft bodies.  Squids and cuttlefishes also have a backbone-like support made of chitin.  They have well developed brains and many can change skin color or texture.  They also use ink as a defense.  It is also believed that they may have come close to being extinct at one point.

There appears to be only one species of Giant Squid.  Given the vast distribution of them, more genetic mutations and cross breeding would be expected.  The findings are published in the journal Proceedings of the Royal Society.  Researchers from the University of Copenhagen and researchers from Australia, Japan, France, Ireland and Portugal took 43 tissue samples from a variety of sources, including stranded animals, remains found in the stomachs of beached sperm whales and accidental by-catch. They then used DNA sequencing techniques to understand the genetic makeup of the squid. Genetic diversity was also found to be very low, meaning that the squid are genetically very similar despite being found all over the world and varying greatly in appearance.

"There's normally local distinction between [animals] genetically," Professor Thomas Gilbert told BBC Nature.  "Things that live in one area eventually become different from things in other areas but [giant squid] are basically identical everywhere."  He suggested that migration could be the key reason specimens from as far apart as Japan and Florida, US are so genetically similar.

"We speculate the larval stage must drift globally in the currents then dive to the nearest dark, deep spot when they are large enough, thus stopping any [population] structure appearing," he explained. "Instead of the adults and their young living in the same place, the young distribute to a completely new place on the Earth every time."

Another theory to explain the large numbers of identical animals is the possibility of a rapid, recent population boom.  The Giant Squid are remarkably able to adjust to their environment.  This, their diverse locations they are found, and their significant size lead scientists to believe the giant squid have a substantial population rather than being as rare as once believed.

The giant squid has been a source of fascination both before and beyond its formal description in 1857 by Danish biologist Japetus Steenstrup.

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