Hi, I'm Erin McCarthy, editor-in-chief of Mental Floss.com. Welcome to Mental
Floss video and did you know that there are more than 500 types of sharks? They
range in size from 8 inches to 40 feet long. My personal favorite is the cookie
cutter shark, which grows to up to 22 inches. It uses its suction cup-like lips
to attach itself to prey and once it's firmly stuck on there
the shark spins its body using its bottom row of serrated teeth to take out
a cone-shaped chunk of flesh. Typically cookie cutters feed off of sea creatures
that are much bigger than them but they've also taken bites out of a couple
of humans and they've been known to leave their mark on submarines, too. And
that's just the first of many awesome facts about sharks that I'm going to
share with you today.
Peter Benchley's 1974 novel Jaws was inspired by a fisherman who caught a
4,500 pound behemoth in Montauk in 1964. The novel wasn't always going to be
called Jaws. Alternate titles included The Stillness in the Water, The Silence
of the Deep, Leviathan Rising, and The Jaws of Death.
Later, Benchley became a conservationist who used his pen to tackle
misconceptions about the fish. In 2006 he said, quote, "I could never write that book
today. Sharks don't target human beings and they certainly don't hold grudges."
Fun fact: Benchley makes a cameo in Steven Spielberg's 1975 adaptation of
his novel. He plays a TV news reporter. Shark attacks, by the way, are actually
very rare. In 2018 there were 66 confirmed unprovoked attacks in America.
The risk of dying from a shark attack is one in three million seven hundred and
forty eight thousand and sixty-seven. You're more likely to be killed by
fireworks, a train crash, or MRSA- that antibiotic-resistant bacteria- than you
are by sharks. Worldwide, the risk is even lower.
There is one particularly ferocious shark that has been known to attack
humans, though. Weighing in at roughly 32 ounces and
covered in brown, fur-like material, this species is totally new to science but we
actually have one here today. Ladies and gentlemen: the Simba shark. Vicious. Sharks
have been around for a while. Thanks to fossils we know that they've
been swimming the seas for at least 400 million years, and some species can live
to be incredibly old. Researchers in 2016 used radiocarbon
dating on the eyes of 28 Greenland sharks and determined that one female
might have been around 400 years old. Speaking of Greenland sharks, their meat
is a delicacy in Iceland. it's called Hákarl. The Sharks meat is
toxic when fresh so it has to go through a fermentation process that involves
burying the shark's body in sand under rocks for 6 to 12 weeks. The meat is then
cut up and hung to dry. The finished product has a strong scent of ammonia.
Anthony Bourdain called it quote, "...the single worst most disgusting and
terrible tasting thing..." he'd ever eaten. Great white sharks have a man-eating
reputation but they're much more interested in seals and sea lions. They
have a forty to fifty-five percent accuracy rate catching their seal
prey, according to research. The hunting process also
often involves the sharks coming fully out of the water, which is called
breaching. Great whites are fast, too. They can swim at 35 miles an hour for short
bursts. That's why many shark researchers think the old tale of "great whites
attack humans because they think we're seals" is a myth. Great white shark
attacks on humans are much less vicious than the way sharks attack prey like
seals and sea lions. One study reported that in 76% of attacks on surfers the
force would not have stunned a pinniped. In most cases they're probably just
curious, though still potentially deadly. One expert told discovery that if you do
spot a shark the best course of action is to remain calm and try to slowly get
back to safety. Despite what you might see in movies and TV,
great white sharks aren't typically found in aquariums, though not for lack
of trying. Since the 1970s aquarium workers who have tried to keep the
sharks in captivity have been having basically the same tragic experience:
finding a great white shark sick, then dead, within a week. While in enclosures
the sharks can't swim at the high speeds or over the distances that they're
supposed to, so they bump into the glass and get hurt, or just stop swimming and
die. Younger sharks have tended to do better. The Monterey Bay Aquarium was
able to keep a young great white for 198 days, but released her after she started
going after other sharks. What are you gonna do? Sharks gonna shark. Another
shark you probably won't see in captivity these days is the tiger shark-
not to be confused with the sand tiger shark, which is a completely different
species found in aquariums around the world. Anyway, female tiger sharks have
many, many pups. After 13 to 16 months of pregnancy a female might give birth to
between 10 and 82 little shark babies. The average is around 30. It's not
unusual for a female shark to give birth to her pups in the place where she
herself was born. One study, which began in 1995 and concluded in 2012, found this
to be the case with lemon sharks in the Bahamas. *Sings* It's not unusual for a female
shark to give birth to her pups in the place where she was born.*Laughing* Female mako
sharks also have an interesting habit. They stay away from male Makos. In
research that lasted for four months a biologist and his team recorded 264
males and 132 females in the East Island area. They found that there was a
clear divide between where males resided versus females and they were baffled as
to why. One of them suggested that it might have something to do with the fact
that males often bite their intended mate,
so maybe the females were trying to avoid that whole situation.
Fun fact: biting is often a part of shark copulation because the males have to
hang on to something. ...Why are so many of my fun facts about animal sex? It's not
just biologists who have taken an interest in sharks. In 2002, software
programmer Jason Homberg went scuba diving on vacation and spotted the rare
whale shark. He wanted to make the spotted sharks less mysterious so he
teamed up with an astrophysicist and a marine biologist. They were able to adapt
an algorithm that had been created for the Hubble Space Telescope program and
use it to start identifying sharks. The algorithm was initially for star mapping,
so it made sense as an algorithm for shark spot mapping. They've since created
a database with 32,000 pictures of whale sharks. The database has helped them
track the animals' locations, which means they can learn more about the whale
shark lifestyle. Of course hammerhead sharks have an identifier as well, but
why do their heads look like that? Well, it may help with hunting. Sharks are able
to sense electric fields in water, which allows them to determine if they're in
the vicinity of prey. One theory is that hammerhead sharks have more of those
sensory organs in their heads so they can find prey better. Their eyes being so
far apart helps, too. They have better binocular vision. In addition to using
electric fields to sense prey, sharks also use them to sense predators. Even
shark embryos have that ability. In a study published in 2013 a group studying
brown-banded bamboo shark embryos found that when the embryos were in the
electric field of a predator their gills stopped moving. Sharks sometimes like to
rest in groups. Nurse sharks and white tip reef sharks have been observed
gathering in groups of 2 to 40, usually in a safe place like a crevice, often
just napping. A basking shark looks very weird when it decomposes. It quickly
loses parts of its jaw and tail, so it's not unusual for people who spot them on
the shore to believe they found a sea monster.
This happened in 1970 in Massachusetts and some scientists believed it happened
again in March 2018. Responsibility for that unidentified sea creature, though,
was eventually claimed by Zardulu the myth-maker,
an artist who specializes in viral hoaxes. In the 1930s a tiger shark at
Coogee aquarium in Australia vomited up a human arm, evidence that became part of
a murder trial. Thanks to a tattoo on the arm the person it belonged to, James
Smith, was identified. It turned out that he was missing and the shark hadn't
bitten the arm off- it was cut off with a knife. There was a suspect, Patrick Brady,
and a man willing to testify that Brady was responsible. But that witness was
shot before the trial. Brady's lawyer claimed that for a
homicide there needed to be a body and all they had was an arm. Brady went free.
The shark, unfortunately, was not so lucky. It died. The deep sea-dwelling goblin
shark has a jaw that shoots outward to grab prey in what scientists have dubbed
slingshot feeding, so it's no wonder they often get compared to monsters. In fact,
Japanese fishermen named them Tengu Zame. Tengu is a demon with a long nose that
sometimes steals children and zame means shark. That's how we got our English
translation, goblin shark. Fun fact: the goblin shark can deploy its jaw at 10.1
feet per second which is roughly twice the speed that New York City pedestrians
walk. By the way, not all sharks are ferocious carnivores. The bonnethead
shark has long been observed to eat sea grass. Until recently it was unclear if
they were digesting it but in 2018 it was confirmed through stable isotope
analysis that they actually were, making them the first known omnivorous shark.
There are multiple types of lantern sharks, including a dwarf lantern shark
that doesn't grow larger than eight inches. These sharks have bellies and
fins that glow so it's thought that when there's a predator swimming beneath them
the predator doesn't know the difference between the shark and the light coming
into the ocean from the sun. We think of sharks as strictly ocean dwellers but
that's not the case for all species. Bull sharks are unusual in that they can
tolerate fresh water. Most sharks have to be in salt water because that's what
their bodies can handle. Put them in fresh water and they'll lose too much
salt. But bull sharks are better able to retain salt in their bodies so they can
travel in fresh water. And, in fact, in 1937 one was caught all the way up in
Alton, Illinois where you wouldn't typically expect to encounter a shark.
Megalodons were huge, perhaps about 50 feet long, but there are now theories
that the measly great white shark, at less than half that size, may have caused
them to go extinct. It was previously believed that they went
extinct around 2.6 million years ago but when a group of paleontologists and
geologists went back through the fossils and data they pegged it at 3.6 million
years ago, which just so happened to be the time that great white sharks were
emerging. They were probably able to go
head-to-head with younger megalodons and out-compete them for food. Just to give
you a better idea of how huge the megalodons were, their teeth could be
around seven inches long. And, in fact, you might want to be on the lookout for them.
In 2018 a couple found a fossilized megalodon tooth on a beach in North
Carolina. One famous megalodon tooth owner was Thomas Jefferson. He loved
fossils and even kept them on display at the entrance of Monticello.
Today, his megalodon tooth is at the Academy of Natural Sciences in
Philadelphia and, of course, he signed it. Finally, a fact about every toddler's
favorite song. Before Pinkfong's version of "Baby Shark" became one of the most
viewed YouTube videos of all time, it was a common song for kids to sing at camps.
But when Jonny Only turned it into the bop that we all know today, he did change
some things. In the original lyrics the sharks attack people and even kill them.
Peter Benchley would not approve. Thanks for watching Mental Floss video which is
made with the help of all these nice people (and Simba). If you have a topic
you'd like us to cover leave it in the comments. Don't forget to subscribe to
our channel, give us a like if you enjoyed the video and, most importantly,
to live every week like it's Shark Week. We'll see you next time!