Shark Angels

http://www.grindtv.com/outdoor/excursions/post/stunning-great-white-shark-attack-images-are-a-mystery-no-longer/

A spectacular photo of a great white shark in airborne attack mode, with the rising sun as a backdrop, was posted to Reddit on Wednesday and picked up by other websites. But the mystery photo contained no details—beyond what was offered in the 400-plus comments—and no photo credit.

“This great white shark jump photo is majestic, awesome, scary,” reads the headline above a post on MSN.com.

Click on the link above for the rest. Explanation to the flawless icon I’m using.

Shark Senses

  Smell

Sharks have keen olfactory senses, located in the short duct (which is not fused, unlike bony fish) between the anterior and posterior nasal openings, with some species able to detect as little as one part per million of blood in seawater.They are more attracted to the chemicals found in the guts of many species, and as a result often linger near or in sewage outfalls. Some species, such as nurse sharks, have external barbels that greatly increase their ability to sense prey.

 Sight Shark eyes are similar to the eyes of other vertebrates, including similar lenses,corneas and retinas, though their eyesight is well adapted to the marine environment with the help of a tissue called tapetum lucidum. This means that sharks can contract and dilate their pupils, like humans, something no teleost fish can do. This tissue is behind the retina and reflects light back to it, thereby increasing visibility in the dark waters. The effectiveness of the tissue varies, with some sharks having stronger nocturnal adaptations. Sharks have eyelids, but they do not blink because the surrounding water cleans their eyes. To protect their eyes some species have nictitating membranes. This membrane covers the eyes while hunting and when the shark is being attacked. However, some species, including the great white shark(Carcharodon carcharias), do not have this membrane, but instead roll their eyes backwards to protect them when striking prey. The importance of sight in shark hunting behavior is debated. Some believe that electro- and chemoreception are more significant, while others point to the nictating membrane as evidence that sight is important. Presumably, the shark would not protect its eyes were they unimportant. The use of sight probably varies with species and water conditions. The shark’s field of vision can swap between monocular and stereoscopic at any time.

Hearing Although it is hard to test sharks’ hearing, they may have a sharp sense of hearing and can possibly hear prey many miles away. A small opening on each side of their heads (not the spiracle) leads directly into the inner ear through a thin channel. The lateral line shows a similar arrangement, and is open to the environment via a series of openings called lateral line pores. This is a reminder of the common origin of these two vibration- and sound-detecting organs that are grouped together as the acoustico-lateralis system. In bony fish and tetrapods the external opening into the inner ear has been lost.

Electroreception

Electromagnetic field receptors (Ampullae of Lorenzini) and motion detecting canals in the head of a shark. The Ampullae of Lorenzini are the electroreceptor organs. They number in the hundreds to thousands. Sharks use the Ampullae of Lorenzini to detect the electromagnetic fields that all living things produce. This helps sharks (particularly the hammerhead shark) find prey. The shark has the greatest electrical sensitivity of any animal. Sharks find prey hidden in sand by detecting the electric fields they produce. Ocean currents moving in the magnetic field of the Earth also generate electric fields that sharks can use for orientation and possibly navigation.

Lateral line This system is found in most fish, including sharks. It detects motion or vibrations in water. The shark can sense frequencies in the range of 25 to 50 Hz.

Swell Shark

WWF on bycatch.

Rodney Fox Great White Shark Expeditions

Andrew could clearly see the strap still flapping from his body, as it was still wrapped around him, deeply embedded into his flesh and gills. Perhaps this shark knew that this was his best chance of survival and amazingly, Strappy circled close again once more, enabling Andrew to lean out, grab one end of the strapping and as the shark swam off, the entire strap pulled through and came free of his body.

Read the full story on Strappy the Shark here: