Because of these characteristics, many experts consider bull sharks to be the most dangerous sharks in the world. Historically, they are joined by their more famous cousins, great whites and tiger sharks, as the three species most likely to attack humans.
The largest is the whale shark, which has been known to get as large as 18 meters (60 feet). The smallest fits in your hand. And the great white shark is somewhere in the middle.
The least aggressive shark is the nurse shark. They are slow-moving and docile, and are not known to attack humans unless provoked.
Next on the scale of most dangerous sharks, the tiger shark is a close second to the great white, killing 36 humans with an unprovoked attack on 138 people in history. The tiger shark gets its name from the unmistakable dark stripes alongside its 14-foot body and can weigh up to 2000 pounds.
It's thought that megalodon sharks became extinct in part due to climate change: as oceans grew colder, they may not have been able to regulate their temperatures as needed. Lack of prey could be behind the megalodon's extinction, as many marine animals and fish could not survive the cold temperatures.
Leedsichthys problematicus, meaning "Alfred Leed's problem-causing fish", was another prehistoric ocean giant. Estimates put Leedsichthys at approximately 16.5m long, substantially larger than the average Megalodon.
The second biggest shark in the world is the basking shark
While they don't get quite as large as whale sharks, the largest one ever reliably measured was 12.27 metres or just over 40 feet long. This is enough to net them the title of the world's second-largest shark.
Wikipedia The White Shark, more commonly referred to as the "Great White," has been reported to be involved in more attacks on humans than any other shark. Fossil remains suggest the Great White dates back to the early Eocene eras, which lasted from about 56 to 34 million years ago.
Do tiger sharks attack humans? It is true that tiger sharks are considered to be particularly aggressive because of its little selectivity but accidents (and they are accidents, not attacks) with humans are rare. Keep in mind though that shark bites, all species included, are very rare.
The earliest megalodon fossils (Otodus megalodon, previously known as Carcharodon or Carcharocles megalodon) date to 20 million years ago. For the next 13 million years the enormous shark dominated the oceans until becoming extinct just 3.6 million years ago.
No physical evidence has been found that would prove the creatures existence, although believers often point to the half-eaten carcasses of whales that sometimes wash ashore in the area.
Hour after hour of small bite after small bite, the orcas would slowly whittle megalodon down. Still, if there were a single mistake, megalodon would easily dispatch the orca in a single bite, but another would always be there to take its place.
The whale shark (Rhincodon typus) is the biggest of all shark and fish species alive, growing up to 55 feet long. It populates the tropical and warm temperate waters worldwide.
Megalodons are extinct. They died out about 3.5 million years ago.
Current estimates say that the megalodon officially went extinct around 3.6 million years ago during the early Pliocene period, although it could have been a little bit after when the last stragglers officially died off.
Mature megalodons likely did not have any predators, but newly birthed and juvenile individuals may have been vulnerable to other large predatory sharks, such as great hammerhead sharks (Sphyrna mokarran), whose ranges and nurseries are thought to have overlapped with those of megalodon from the end of the Miocene and ...
Dolphins use their strong snouts as a powerful weapon to ram sharks, targeting their soft underbellies and gills to cause injuries. Sharks pose less of a threat to larger members of the dolphin family. Indeed, orcas are the top predator in the ocean and small sharks are a target for some populations.
The smallest shark, a dwarf lantern shark (Etmopterus perryi) is smaller than a human hand. It's rarely seen and little is known about it, having only been observed a few times off the northern tip of South America at depths between 283–439 meters (928–1,440 feet).
Tiger sharks can blend in only so much, though—their average length is around 14 feet, but they can be longer than 20 feet. Tiger sharks are known for being aggressive, and it's true that they are second only to great whites in numbers of shark attacks on humans.