Showing posts with label deep sea. Show all posts
Showing posts with label deep sea. Show all posts

Tuesday, July 16, 2013

Giant Squid First Time on Film


Giant squid, like all squid, have sharp beaks, not unlike those of a parrot. They use them for biting into the fish and invertebrates that they eat. In the stomach of a Sperm whale, those beaks can accumulate. In fact, Sperm whales are often found to have thousands of the beaks in their stomachs!

But the sharp beaks irritate the stomach lining. As a reaction to the irritation of all the squid beaks, the whale produces in its intestines a cholesterol derivative which has come to be called ambergris. First discovered in ancient times as a substance of unknown origin which would wash ashore, it wasn't until the whaling era that the true source of the material was found.

When it is first removed from a whale, ambergris is a thick, black, foul-smelling liquid. Later, it hardens into a waxy aromatic substance. When heated, it produces a pleasant earthy aroma. It was used as a fixative in perfumes because it causes the scent of perfume to last much longer. The Greeks, Chinese, Japanese and Arabs have all held ambergris in high regard. Today we have synthetic substances which accomplish the same thing, so there is no need to hunt whales for it, and trade in ambergris is now banned worldwide by treaty. Yet, every once in a while a rare piece will still wash ashore somewhere.

Friday, August 24, 2012

Giant Squid Eyes


 


The giant squid sees the world with eyes the size of soccer balls. They’re at least 25 centimetres (10inches) across, making them the largest eyes on the planet.
Why does the giant squid have a champion eye that’s at least twice the size of the runner-up?

Dan-Eric Nilsson and Eric Warrant from Lund University, Sweden, suggest that the world’s biggest eyes evolved to spot one of the world’s biggest predators – the sperm whale.

Using a mathematical model, they found that in the deep ocean, eyes suffer from a law of diminishing returns. Small eyes can see dramatically further if they grow a bit bigger.

Using their model, Nilsson and Warrant found that enormous eyes have advantages over eyes that are merely large. Specifically, they’re much better at spotting other large objects that give off their own light, in water deeper than 500 metres. There’s one animal that fits those criteria, and it’s one that giant squids really need to see: the sperm whale.

But in the dark oceans, how could the squids see them? Nilsson and Warrant note that while sperm whales don’t produce their own light, they frequently disturb animals that do. When they dive, they knock tiny animals like jellyfish and crustaceans that flash in response.
These shimmering outlines would be too faint for most animals to see, but not the giant squid. Nilsson and Warrant showed that its huge eyes could pick up this light from 120 metres away, and they can scan a huge sphere of water for those tell-tale flashes.

From: http://blogs.discovermagazine.com/notrocketscience/2012/03/15/giant-squid-what-big-eyes-you-have-all-the-better-to-spot-sperm-whales-with-my-dear/

Tuesday, August 7, 2012

The Amazing Mantis Shrimp


"Mantis shrimp or stomatopods are marine crustaceans, the members of the order Stomatopoda. Mantis shrimp sport powerful claws that they use to attack and kill prey by spearing, stunning or dismemberment. Although it happens rarely, some larger species of mantis shrimp are capable of breaking through aquarium glass with a single strike from this weapon."


"One species possess a developed club and rudimentary spear; the club is used to bludgeon and smash their meals apart. These two weapons are employed with blinding quickness, with an acceleration of a .22 calibre bullet."
The mantis shrimps' eyes can perceive both polarized light and hyperspectral colour vision. They are considered to be the most complex eyes in the animal kingdom.

Some species have at least 16 different photoreceptor types, which are divided into four classes (their spectral sensitivity is further tuned by colour filters in the retinas), 12 of them for colour analysis in the different wavelengths (including four which are sensitive to ultraviolet light) and four of them for analysing polarised light. By comparison, humans have only five visual pigments, four dedicated to see colour but the lens block ultraviolet light.