The giant squid is one of the most enigmatic animals on the planet. It is extremely rarely seen, except as the remains of animals that have been washed ashore, and placed in the formalin or ethanol collections of museums.
But now, researchers at the University of Copenhagen leading an international team, have discovered that no matter where in the world they are found, the fabled animals are so closely related at the genetic level that they represent a single, global population, and thus despite previous statements to the contrary, a single species worldwide. Thus the circle, that was first opened in 1857 by the famous Danish naturalist Japetus Steenstrup as he first described the animal, can be closed. It was Steenstrup that realized this beast was the same animal that in the past gave rise to centuries of sailors tails, and even in more recent became immortalized by writers such as Jules Verne and Herman Melville, by demonstrating that the monster was based in reality, and gave it the latin name Architeuthis dux.
It was less than 1 year ago, that the giant squid, Architeuthis dux, was first filmed alive in its natural element. Taken at a depth of 630m and after 100 missions and 400 hours of filming, the footage was captured by a small submarine lying off the Japanese island of Chichi Jima – near to the famous Iwo Jima that was the scene of some of the bloodiest fighting between Japan and the USA in the Second World War.
Now, PhD student Inger Winkelmann and her supervisor Professor Tom Gilbert, from the Basic Research Centre in GeoGenetics at the Natural History Museum of Denmark, Copenhagen University, have managed to place new bricks into the puzzle of this giant 10 armed invertebrate, that is credibly believed to grow up to 13 meters long and way over 900 kg.
And the two scientists conclusions are: No matter what a sample looks like, its one species all over the deep oceans of the planet.
Sinking to the depths
-We have analysed DNA from the remains of 43 giant squid collected from all over the world. The results show, that the animal is genetically nearly identical all over the planet, and shows no evidence of living in geographically structured populations. We suggest that one possible explanation for this is that although evidence suggests the adults remain in relatively restricted geographic regions, the young that live on the ocean’s surfaces must drift in the currents globally. Once they reach a large enough size to survive the depths, we believe they dive to the nearest suitable deep waters, and there the cycle begins again. Nevertheless, we still lack a huge amount of knowledge about these creatures. How big a range to they really inhabit as adults? Have they in the past been threatened by things such as climate change, and the populations of their natural enemies, such as the planet’s largest toothed whale, the sperm whale that can grow up to 20 m in length and 50 tons? And at an even more basic level…how old do they even get and how quickly do they grow?