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The 3 Most Passive Sharks Known to Man
Most people are afraid of sharks, but they shouldn't be afraid of all sharks. Even the biggest, scariest sharks could end up being less dangerous than some of the smallest.
The Whale Shark
The whale shark is the largest out of our three growing to an average of 41.5 feet and weighing an average of 41,000 pounds. Whale sharks are one of the only filter-feeding sharks. Whale sharks have very large mouths, sometimes nearly 6 feet wide, however they don't eat big things, but rather gulp in large quantities of water full of plankton and small fish. Unlike other filter-feeders, which coast along passively, whale sharks are active eaters. When a whale shark swims into a school of fish it swims with it's mouth open and bobs it's head back and forth to sweep in the greatest number of fish. Over 1,500 gallons of water can pass through it's gills each hour! Whatever is left behind - plankton and small fish caught in the sharks gill rakers - is then swallowed.
Until recently, it was believed that whale sharks were solitary filter-feeders that roamed the open ocean alone, but in 2011 experts discovered that whale sharks gather in impressive numbers for, what appears to be the main draw, food! 420 whale sharks were seen together near Mexico's Yucatan Peninsula in the spring of 2011. Research done by Smithsonian Conservation Biology Institute revealed that the whale sharks had gathered to feed on dense patches of fish eggs.
While the word "whale" appears in their name whale sharks aren't whales at all; they earned their name "whale" is solely for their impressive size. Across the globe the whale shark has many different names and not all of them are related to the shark's magnitude. In Vietnam, whale sharks are known as ca-ong, or "sir fish," likely out of respect for their large size. Throughout Latin America, whale sharks are named for the white spots on their backs, and are called "pez dama" or "domino." A few areas of the world refer to the spots on a whale shark's back as "stars." For example, the Japanese name for whale sharks, "geger lintang," means "stars on the back." In Madagascar whales sharks are called "maokintana," meaning "many stars." One of the fun nicknames for the whale shark is "papa shillingi" which is used in Africa. This nickname in Kenya came from the myth that God tossed shillings upon the backs of these large fish.
The Basking Shark
The second-largest shark may look like a terrifying vacuum that could inhale anyone or thing, but is actually a peaceful ocean grazer, posing no threat to humans. The max length of a basking shark is about 40 feet and weighing about 21 tons. Basking sharks swim down 6500 feet to feed on deep sea plankton. The basking shark's mouth is about 3 feet in width. The basking shark relies on passively moving water through its mouth in order to eat. The basking shark has to take in a huge amount of water to get enough food; as much as 2000 tons of water moves through its gills every hour! The basking sharks' gill rakers are bristle-like structures made from the same material as their dermal denticles, which is the same material that a great white sharks skin is made of. The thousands of these bristles each measure 3 inches long. Every few minutes, the basking shark flutters its gills and swallows the food that has accumulated there. The basking shark sheds and regrows its rakers each winter, the only known example of an annual molt in fishes.
Basking sharks are most likely to be found near the surface in the North Atlantic through the warmer months of spring, summer, and fall where the plankton is more abundant. For many years no one could figure out where the basking sharks went during the winter. In 2009, scientists at the Massachusetts Division of Marine Fisheries decided to solve the mystery and tag a group of basking shark and track them using satellite-based technology. The scientist had been surprised when they had got a transmission from their satellite telling them that they found out their tagged sharks were in deep waters off the coast of Brazil. No one knew that they traveled so far but at least they know where some of them go. A similar study showed that basking sharks off Devon and Cornwall, England, had migrated to much deeper waters off the continental shelf in winter. Tracking the data showed that they spent most of the winter at depths of 3000 feet or more feeding on a plankton-rich soup.
It makes perfect sense why the basking shark has been mistaken for giant sea monsters. Their dorsal fin is enormous, and they have a giant tail fin to go with it and they typically swim in pairs or even schools of up to 100, traveling nose to tail in single file. From far off a school of basking sharks could look like a giant sea serpent to the untrained eye. Many sea serpent sightings over the years ended up being a group of basking sharks out for a cruise. Further complicating things, when a dead basking shark deteriorates, its long neck and tiny skull can resemble a plesiosaur, a marine reptile that lived from 205 to 65 million years ago. Several carcasses have been mistaken for these long-necked giants from the Age of Dinosaurs. In Scotland in 1808, a dead basking shark had washed ashore Orkney Islands which was given the name of the "Stronsay Beast." It was categorized as a new species with a scientific name meaning "Pontoppidan's sea-snake" after a scientist who published a work on giant sea serpents in the 1700s. Eventually, it was revealed to be the body of a decayed basking shark.
The Megamouth Shark
Lastly, our megamouth shark, which is the smallest out of our three growing to a length of 18 feet and weighing about 2,700 pounds. The difference with our megamouth is it was unknown to science until 1976. With it only having been discovered 41 years ago and less than 100 have been seen, no one really knows much about these deep sea giants. The megamouth cruises through groups of krill with its mouth wide open, pushing out its jaw and expanding its baccal cavity to suck prey inside, then expelling water through its gills.
Nobody knows for sure where megamouths live, but the majority of the megamouth discoveries have been in equatorial regions of the Indian, Pacific and Atlantic oceans. If you were lucky enough to come across a megamouth there are some defining factors that make a megamouth different from other filter-feeding sharks. Their snout is surprisingly short, but very broadly rounded. Its blunt snout is one of the features that allows the megamouth to open wide and suck in giant mouthfuls of plankton. Their skin is different from other sharks which is loose and flabby as apposed to the smooth, taut skin of other sharks have to reduce drag, allowing them to swim quickly and ambush predators. The megamouth's skin drags along in the water which makes them more sloth-like while swimming.
The slow-moving megamouths are related to the world's fastest sharks: the shortfin mako and the salmon shark. Other relatives include the great white, thresher sharks, sand tigers, the slow-moving basking shark, and the equally bizarre goblin shark. These sharks are collectively called mackerel sharks or Lamniformes. This is the oldest group of sharks which have existed close to or over 120 million years. Most are warm blooded, which means that they can raise their body temperature to adjust to the water temperature. This gives them extra speed, and the fastest swimmers in the shark world are mackerel sharks. Not megamouths however which, like basking sharks, cruise along slowly sucking plankton. Many mackerel sharks prefer warm waters, but some, such as salmon sharks, can survive in icy waters. Some swim near the coastline in shallow water; others, like the megamouth, are deep-sea sharks that live thousands of feet beneath the surface.
shark comparison chart