Analysis / Threatening Shark

• In Real Life, sharks play a very important role in the marine ecosystem, and their presence is a good sign of cleaner, more productive seas.
  • No, sharks do not become chronic maneaters like some mammalian carnivores. There is no such thing as a "rogue shark" which habitually makes a point to attack humans it finds as easy prey. Cases of multiple persons harmed by sharks in a small area within a relatively short time are just sad coincidences for the victims involving multiple animals.
  • No, sharks do not go into a berserk feeding frenzy upon smelling blood any more than any other carnivore would. When they are attracted to blood, they overwhelmingly prefer fish blood.
  • No, sharks can't pick up a drop of blood across square miles of ocean water. While they can smell blood, there needs to be a significant amount pouring for a reasonable amount of time as smells travel slower in water than in air.
  • No, sharks do not jump out of the water to attack persons on boats. Various species might breach, but this is likely because they're attacking something just below the surface and inertia kept them going.
• The megalodon, a forty foot — that's the minimum estimate — long prehistoric super shark. Also believed to have had one of the most powerful bite forces in the history of the animal kingdom. As well as a number of other large (and often freakish-looking) prehistoric sharks. Want some examples?
  • Helicoprion was as large as a great white and had a circular saw-shaped bottom jaw lined with hundreds of teeth; its relative, Edestus, aka the scissor shark, had a line of teeth permanently sticking out of its mouth on both jaws. Although Helicoprion is now thought to have been a ratfish, not a shark. Not that this makes it any less badass, though.
  • There's also Xenacanthus, a freshwater shark that managed to live through two mass extinctions events (one of which wiped out 95% of all life) and had a cool looking spike on its head. Its close relative, Orthacanthus, was a shark with fangs — basically a shark crossed with a crocodile. Stethacanthus had a dorsal fin in the shape of an anvil and tiny spines covering it and its head, and Cretoxyrhina, a Cretaceous shark about as large as the great white with tiger shark-like jaws and teeth deadly enough to give it the nickname "Ginshu shark" that lived in one of the most monster-filled seas in Earth's history.
• Reality has a habit of subverting trends or tropes even often parroted in outdated documentaries, showing this trope is so pervasive as to even color perceptions of sharks in media that was supposedly informative a few decades ago.
  • At first the Tiger shark seems like a classic example. To explain, Tiger Sharks are Extreme Omnivores and will seemingly eat absolutely anything they can. Things found inside tiger shark stomachs include license plates, bones of various animals normally too large to fit inside to begin with (like horses), and supposedly (according to a 16th-century report by a respected marine biologist of the time) even the remains of a medieval knight still clad in his armour. This sounds threatening, until you remember the only reason something like a horse would be far out at sea would be if the carcass washed off shore and the Tiger Shark was merely scavenging. The same can be said for the inedible objects sometimes injested purely on accident.
  • Bull sharks are often reported as being violently unpredictable and aggressive behavior, and have been known to attack people without provocation. They also have a certain level of tolerance for fresh water meaning attacks would be comparatively more common. Just when you thought it was safe to go in the rivers. After all, just read about the Jersey Shore Attacks of 1916. Pure terror; it was so scary, it was the main inspiration for Jaws^note It should be noted that they did catch a Great White Shark that had human remains in its stomach however it remains debated if this was the (only) shark responsible for the attacks. This again, sounds threatening. Until you remember the primary reason bull sharks even go into freshwater is its because females prefer fresh and shallow waters as nurseries for their babies. Almost all of the big bull sharks implicated in attacks turned out to be pregnant mothers-to-be whom were potentially more aggressive due to stresses therein and the need to protect their unborn. And even with them being astronomically more common in areas people frequent with choppy, murky water that makes attacks more likely; the chance of a bite is still astronomically low. Their number of seemingly unprovoked attacks is far outweighed by provoked incidents where people trying to catch, kill, or harass the shark were injured.
• Pilot fish take advantage of this trope, forming a symbiotic relationship with sharks (or turtles or rays); the shark (usually the aforementioned oceanic whitetip) gets parasite removal, while the pilot fish gets a reliable bodyguard in the hostile open ocean.
• Ragged tooth sharks bear live young... which eat each other while still in their mother's womb. Out of the original 15 fetuses, only two generally survive until birth, and even that is only because the womb is split into two sections.
• Subverted by the Whale Shark. It is even more like a whale than the name implies — it is the largest existing shark on earth, and feeds entirely on plankton. It is a Gentle Giant of the seas that lets divers pat it.
  • Basking sharks are harmless to humans, too. Though they look damned weird when their mouths are fully open.
  • Zebra sharks are an adorable species of nocturnal shark which dwell at the bottom of the sea, they appear to be extreme doormats during daylight and even at night, they feed on crabs and bony fish rather than humans. It's still unwise to provoke them, though; they have occasionally bitten divers who did obnoxious things like pulling their tails.
  • The Megamouth shark, a very rare deep-sea shark with a huge mouth, but only eats shrimps.
  • The sand tiger shark. Despite its fearsome appearance and strong swimming ability, is a docile and slow-swimmer with no confirmed human fatalities. Its fearsome appearance and large size with its relative docility makes it a popular choice in public aquariums.
  • This trope is subverted by dogfish, (a type of catshark) the smallest sharks. Most are just one or two feet long, and they're about as cute as fish ever get. Just don't touch them, as their dorsal fins are covered in a mildly toxic venom.
  • A number of shark species are harmless to humans because it is simply implausible for a human to ever share their environment, like the goblin shark which occurs at extreme depths, or the Greenland Shark which lives in frigid arctic waters. Although it's probably pretty good that the Greenland shark does so since some research will find them capable of giving humans nightmares. Such as the one who ate a polar bear. Turns out, that for these things, it's not that Bears Are Bad News, it's that bears are food. The one who was found with an entire reindeer in its stomach deserves an honorable mention as well. Actually, the Inuit has legends of the shark attacking kayaks, and although no confirmed cases of human predation exists, given its willingness to eat bears and reindeer, it is not wholly unlikely that it would take a human from time to time and get away with it due to the fact that that it inhabits a remote, nigh-uninhabited part of the world where the few people living there are unlikely to regularly engage in any recreational water activities,.
  • Great whites, of all things, are not particularly bad as far as large predatory sharks go. While giving them a wide berth is mandatory unless you are extremely experienced (and even people who know what they are doing still know to exercise utmost caution), they are not particularly aggressive towards humans (who, for one thing, are simply not worth their while as prey due to minimal body fat) as long as they are not startled and their personal space is respected. They are far from Gentle Giant status, but unless you're bleeding or have managed to scare them or piss them off, they are generally pretty apathetic towards divers.
• Some sharks can be dangerous to deep sea divers, which is why many who visit sharks in the seas learn to read their body language. Despite essentially being a living torpedo in shape, sharks can convey their intentions by arching their back, shifting their jaws and eyes back, and by swimming in particular patterns. Any diver who ignores or fails to act upon such body language is in danger of failing to spot an impending attack. If a diver learns the tricks, however, they can not only know when best to leave the water but also, with some species, know how to avoid inviting an attack in the first place. One example is to swim below the shark - sharks usually attack from below, so if a diver gets below them, the shark will be wary and will treat the diver as a fellow predator rather than as potential prey.
• The Angelshark which looks more like a Manta Ray. It's generally a bottom dweller that feeds only on other fish. However, if it's provoked or if its tail is grabbed, it can bite and leave grave lacerations because of its sharp teeth.
• The basking shark is a filter feeder, but it's been theorized that their carcasses are responsible for the idea of the Stock Ness Monster and other plesiosaur-shaped cryptids: the lower jaw rots away first, leaving only the spine and fins in a plesiosaur-like shape.