Are Sharks right and/or left handed(finned)?
453069
i think they are both handed because if they were only one part handed when swimming they would start going round and round not properly
675249
Elasmobranchs (sharks, skates, and rays) indeed have an interesting sensory physiology enabling them to sense a variety of physical stimuli.  But fear is not one of them. That said, it is true though that fear may be associated with either the release of particular chemical compounds, but far more importantly and likey in regards to your question, with particular behavior.  And in that sharks are not very different from any other predator.\n\nThe sense of smell is indeed very well established in almost all elasmobranchs; if you ever take a look at a shark's brain note the extremely large bulbi olfactorii, the areas of the brain where smell is first analyzed.  The sentivity of shark noses for blood is often emphasized, but you must not imagine sharks to be "swimming noses."  Rather, they rely on different senses for different environmental conditions, prey, etc. The priority assigned to either one of the possible sensory modes is largely dependent on the life-style of the animal.  Given that there are over 400 different species, there are a few variations.\n\nLike many other aquatic animals (e.g., teleosts, but also amphibians) sharks rely on their lateral line organ for detecting objects in greater distances.  The lateral line organ is a tiny canal running along the side of the animal underneath the skin.  it is open to the environment through a set of pores, through which the shark can sense pressure differences in the water, as they are being produced for example by a fish in distress.  This can of course be misunderstood as "smelling fear," when in fact it is more like "sensing the panicked movements of a potential prey."\n\nThe electromagnetic sense of elasmobranchs is perhaps most amazing from a human point of view, since it is so very different from anything we have.  All elasmobranchs have Ampullae of Lorentzi, with which the animals can indeed sense bioelectric fields.  These organs are so sensitive that a dogfish can sense the bioelectric field induced by the beating heart of a flounder covered by sand.  Sharks also use this organ for a magnetic compass.  By swimming through the earth's magnetic field, a shark will induce an electric current that will either run from its back to its belly (when the animal swims in an eastern direction), or from its belly to its back (in western direction).  with its own electromagnetic sensores, the animal can sense the induced electric current and its direction and can thus orient itself along the magnetic field of the earth.  Again, very sexy and very helpful, but no detector of fear!\n\nNow, some sharks use their eyes when they hunt prey, and this may an important point in regards to your question.  Great white sharks (Carcharodon carcharias) often attack their prey (e.g., seals) from far below, orienting themselves visually in their attack and going for the tell-tale silhoutte of the pinniped.  Some sharks, like the lemon shark (Negaprion brevirostris), have an interesting eye, where the sensitivity of the retina changes from light of one particular wavelength during day time to one of a different wavelength during night time.  This Purkinje-shift allows the animals to see optimally during day and night.  Now, many animals (or humans) in distress show a particular behavior.  Sometimes, a flight response is what is initiated when faced with a predator.  This behavior can signal the shark that the fleeing animal (or human) is afraid and therefore not a danger but rather a potential prey.  Consequently, fear in humans that cause a flight response may cause sharks to respond accordingly.  This may also be misunderstood as "smelling fear."  This, by the way, is the same kind of behavior a cougar, dog, or bear will dislay.\n\nThat said, there is always the possibility that during fear a human may release certain chemical compounds that the shark can smell.  But I doubt that this is something really significant in a real-life encounter.\n\n
596083
yes i was in Tobago 2003 in the man of war bay. I was in a canoe.It was also my first time trying this sport. I was told no sharks come into the bay yet this one did. It was jumping out of the water rather close to me, Scared me silly. Unfortunately a few days later the local fishermen caught one. a hammer head shark. Lovely to look at but would have been better if it was alive in the sea.
203339
The dorsal fin is the part that the shark has above the surface of the water.
257906
The normal way.\n\nEnemies?  Humans. Large fish. Codfish, haddock, octopii.
695107
Sharks (superorder Selachimorpha) are fish with a full cartilaginous skeleton and a streamlined body. They respire with the use of five to seven gill slits.  Sharks belong to the superorder Selachimorpha in the subclass Elasmobranchii in the class Chondrichthyes. The Elasmobranchii also include rays and skates; the Chondrichthyes also include Chimaeras. It is currently thought that the sharks form a polyphyletic group: in particular, some sharks are more closely related to rays than they are to some other sharks.\nDolphins are highly intelligent aquatic mammals that are closely related to whales and porpoises. All Dolphins belong to the Suborder Odontoceti, and Family Delphinidae, or Platanistoidea. There are almost forty species of dolphin in seventeen genera. They vary in size from 1.2 m (4 ft) and 40 kg (88 lb) (Maui’s Dolphin), up to 9.5 m (30 ft) and ten tonnes (the Orca).
854620
no, sharks are NO invertebrates, they got a spine
1072511
I was able to find a black marlin @ 1560 Lbs caught in Peru  and a Greenland shark caught in Norway that weighed in at 1708lbs 9oz!  I didn't find any pics but if anyone has them I would like to see them.
145520
Both are hydrodynamic, that is, with the fusiform shape that is best to "pierce" the water when moving forward. In addition, such a shape maintains a laminar water flow around them (as opposed to turbulent). A laminar flow ensures support of the body (as opposed to sinking).\nMovement in water differs from terrestrial movement because the body may move in 3 dimensions; therefore, fish fins (comparable to the "flaps" of submarines... well I know nothing about submarine architecture so I guess that's not their name) counteract pitch (up/down tilt), yaw (left/right) and roll (rotation around the greater body axis).
952619
The tails of fish and whales are different because they are the result of different evolutionary pathways, not because of direct functional factors. It is in fact an example of what happens when organisms with different structures, abilities and constraints are faced with the same functional requirement. \n\nFish have relatively simple vertebrae; in most cases, the vertebral centers look like biconcave cylinders that contact each other. This type of vertebrae allow the vertebral column to undulate laterally, and the tailfins of fish have evolved in a vertical arrangement, so that the lateral axial movement of the body moves the tail to provide thrust.\n\nIn contrast, the vertebrates that evolved adaptations for life on land, the tetrapods, don't have this type of vertebra any more. Our vertebral bodies are locked together by means of special apophyses (outgrowths). And although lizards and snakes undulate laterally, we mammals have lost that flexibility (as part of a different body structure that allows a different arrangement of lungs for respiration, etc). However, we can flex the spine up and down (or forward and backward, in humans) and many mammals that are fast runners use dorsoventral flexion/extension as part of their locomotion (if you've seen a film of a running cheetah, you know what I mean).\n\nNow, aquatic mammals use their limbs (more or less transformed into flippers) and tail to move in the water. They use the same powerful up-and-down body undulation as their ancestors used on land; in fact, this undulatory locomotion has been documented for a fossil ancestral whale,  Ambulocetus (see link).\n\nSo in this case, as in many others, we see more than one solution, and all are "optimal" (both are hydrodynamically efficient), but different because their evolutionary paths were just different, not better or worse.
97580
Easy. Sharks belong within the subphylum Vertebrata.
1115588
Hey first off DON'T listen at all to the hippie nonsense garbage about Sharks being "endangered"! That is a load of grade A bull. Shark populations are exploding,we need to hunt them to reduce the OVER population. My opinion is bite then before they bite you. This how you clean them:After you have shot the top of the shark in the head with a explosive tip deer slug; death and paralysis ensues. Cut the tail off to drain the max. amount of blood out of the shark,then hack/saw the head off then slice the belly open and plop out the guts in a top down fashions. then skin and fillet as you would any other fish and enjoy fried,baked,in tacos,stewed! Save the teeth as a souvenir!!
812272
Some fish have internal, some have external! You are obviously just talking about "oviparous fishes."  (There are some fishes with "gonopodia" which are penis-like fins that penetrate the side of the female and are used as an intromittent organ.  Look up molley and platty MATING-PARING sexual behaviors.) These fish mate (not just breed with a spawning) and are ovoviviparous and give "birth." (not true birth like placental mammals.)\n\nThe zygote of oviparous anamniotes, however, is generally NOT that safe in the water!  The very high number of eggs-sperm usually released-spawned and fertilized, however, helps the odds of some of the eggs surviving thru development.  The mucus nature of anamniotic eggs helps prtect some, but not that much.  The eggs are vulnerable to fungus and bacterial infection and to predation by other organisms. \n\nThere is a huge array of behaviors that many different species of fishes use to help protect their broods. Some are mouth brooders, some lay them clinging to rocks, into the sand or into crevices.  Some lay them and stay nearby fanning them and guarding them.  Eggs of seahorses are laid into the pouch of the male and he gives "birth." If you go thru ichthyology books, websites and investigate parental care of broods, you will come up with a HUGE range of behaviors exhibited by the various species of fishes.  Even some species of sharks lay eggs, but their eggs are often camoflauged in the seaweed or along the ocean bottom.
114432
Ok, I know that the bit about sharks not breathing if they're still is still taught at school, and essentially it has some point. It's true that gill oxygenation is better when the water flow through the branchial area is greater. \nBut sharks DO indeed stop swimming, they can rest near the bottom of the ocean (as if sleeping) and they use the pumping motion of the floor of their mouth (their mostly immobile tongue) to help water move through the gills. \nBut as I've said, immobile sharks lie mostly near the ocean floor. This is because they're rather dense with respect to water (they don't have swimming bladders like bony fishes do), although their enormous, fat-filled liver increases their buoyancy significantly (along with other physiological characteristics). When they swim, sharks can keep themselves in midwater; the movements of the trunk and tail generate the necessary thrust to keep them from falling to the bottom.
219522
The answer is a combination of several factors.\n\nThe skin is designed so as to limit "wrinkling" while swimming. (hydrodynamics) If u look at the skin closely, they consist of placoid scales which r smooth in one direction (swimming direction), and rough in the other direction.\n\nSharks r seriously buffed up, which aids in generating work.\n\nFins stabilise the body to prevent it from swimming upside down or in a circle\n\nThey belong to the chondrichthyes... cartilaginous fishes. This skeletal system is lighter than boney frames and allows for greater flexibility. Both characteristics COULD help in swimming. (There r, however, many fast marine animals with boney frames such as the dolphin or swordfish).\n\nThe tail is the main propulsion force. Which works in coordination with it's respiratory and circulatory system. As water passes over the gills, the lamellae r oxygenated, and at the same time release waste products (co2). So, if the shark swims slowly, the respiration rate decreases... and if he doesn't swim at all, he suffocates. I guess sharks swim fast because they have to. Haha. I hope that's helpful.
2710
There are more than 360 described species of sharks.\nThere are eight orders of sharks:\n\n    * Hexanchiformes\n    * Squaliformes\n    * Pristiophoriformes\n    * Squatiniformes\n    * Heterodontiformes\n    * Orectolobiformes\n    * Carcharhiniformes\n    * Lamniformes
905959
Yes. Bilateral symmetry. The are symmetrical from side to side.\n\n;-D Don't go in the water when they are hungry!