Why the cuttlefish ink?
It is well known that the ability of cephalopods — cuttlefish, octopuses, squids — “to throw dust in the eyes”. In a moment of danger, these animals throw themselves out of a jet black liquid. “Ink” spread out in the water with a thick cloud, and under the guise of “smokescreen” clams trying to evade pursuit.
“Ink” the squid produces a special body — the pear-shaped excrescence of the rectum — it is called the ink bag. This dense bubble, divided by a partition into two parts. The lower half is a special gland that produces black paint. After that she goes to “the warehouse” — is pumped into the upper part, where it is stored until the first alarm.
The shade “ink” is not at all the same cephalopods: cuttlefish it blue-black, octopus — black, squid — brown. Cuttlefish are known to people since time immemorial, and we can say that these animals left their mark in human culture because for many centuries people wrote their “ink”.
Not all the contents of the ink SAC is thrown at a time. Ordinary octopus can put “smokescreen” six times in a row, and in half an hour fully restores the entire stock of spent ink.
The ink capacity of the ink fluid are unusually large. Cuttlefish for 5 seconds paints ejected “ink” all the water in the tank capacity of 5.5 liters. While the giant squid spewing out ink fluid so that the waves become turbid over a space of a hundred meters.
Relatively recently, biologists made a surprising discovery. The observations showed that ejected cephalopods liquid dissolves immediately, but long — up to ten minutes and more — hangs in the water dark and compact drop. The most striking thing is that the shape of this drop resembles the shape of the animal threw her. A predator instead of escaping victim grabs her ethereal double. That’s when she explodes and envelops the enemy in a dark cloud.
Interesting to see how aggressive the shark comes into complete confusion, when a gaggle of squid at a time, from multi-barreled mortar, throwing a series of “ink bombs”. The predator rushes in all directions, enough imaginary one squid after another, and soon all disappears in a dense cloud dispersed ink.
Some cuttlefish living in the eternal darkness of the depths, by contrast, spews bright, luminous cloud that causes enemies in the same confusion.
A lot of trouble to octopus Moray delivers. When the monster broke through the “smokescreen” trying to seize the fugitive, the stone falls to the bottom. But strangely, Moray several times poked the petrified octopus and then… sailing on. What happened to the bloodthirsty Moray, why is she not grabbed the victim? It turns out that the “ink” of octopi possess the properties of the drug and paralyze the olfactory nerves morays! Having been in the ink cloud, it loses the ability to recognize the smell of the lurking fugitive. More hours lasts paralyzing effect of the drug octopus!
You will be weird to hear that there are many living beings for whom “lifting himself by the hair” is the usual way they move in the water. A squid moving through the water in this way: he takes the water into the Gill cavity through the side opening and a special funnel in front of the body, and then vigorously throws a jet of water through said funnel; however, it is the law of anti – reverse gets a boost, enough to quickly swim back and sides of the body. Cuttlefish can, however, guide the tube hopper to the side or back and, rapidly squeezing out water from it, to move in any direction.
Based on the same and the movement of the Medusa: the contraction of muscles pushes it out from under my bell-shaped body of water, receiving a push in the opposite direction. A similar example is used when the movement of the larvae of dragonflies and other aquatic animals.