nothing strikes fear in the heart of humans more than the thought of a great white shark even writing this video gave me some extreme bouts of queasiness in our modern comfortable life we almost never have to think about being hunted ripped apart and eaten but looking into the eyes of a great white shark any comfort we might have felt gets ripped away deaths from great white sharks are not unheard of and I know many people who won't step foot into the ocean because because of this intense and primal fear but with this Primal Fear comes a morbid fascination with one of the most formidable Predators the world has ever seen these monstrous fish can reach up to 20 ft or 6 M long and can weigh up 2,270 kg or 5,000 lb their rows of coarsely serrated sharply pointed teeth are built to tear through flesh and shatter bone it's it's no wonder that Hollywood can't resist portraying them as crazed and indiscriminate Hunters attacking people boats and anything else at random ripping off arms and legs just for fun and while great whites do sometimes kill humans their attacks are not random and in fact form unexpected patterns in space and time their kills are purposeful and ritualistic and most of the advice we've heard about how to avoid a great white shark attack isn't necessarily true great white sharks are so much more than brutal killers they are sophisticated Elusive and smart animals they have extremely sharp vision and the keenest sense of smell of any shark and maybe of any animal in the ocean and scientists are realizing that they may be far more intelligent and delicate than we give them credit for so much so that aquariums the world over have notoriously failed to keep them in captivity hundreds of experts and millions of dollars in resources have not been enough to crack the code of how to keep them in man-made tanks but as much as we've learned about their biology great white sharks continue to surprise and baffle the scientific world just how powerful is a great white shark and how does it decide what it's going to attack and what it's going to eat and what about great white sharks makes them unable to survive living in captivity [Music] great white sharks are enormous fish with a body shaped like a blunt torpedo with a sharply pointed conical snout large pectoral and Dorsal fins and a strong crescent-shaped tail they have a dark gray coloration on their back and sides and only their belly is white they were given their name from the days when they were only observed by Whalers who saw the whites of their bellies while the sharks feasted on the whales the humans were trying to harvest which they often do upside down enabling this nashing and tearing are the white shark serrated triangular teeth the points are for puncturing the serrations for ripping around 50 teeth are exposed in in use lined up in rows at the top and bottom of the mouth but Behind These rows are six more rows of teeth each at a different stage of development unlike humans whose teeth are set into the bone shark teeth are set into the gun s and while grabbing and subduing thrashing prey many of these teeth fall out thus the shark needs to replace them often the teeth and the extra rows in the back will move forward as the teeth in the front are lost a great white shark will go through around 30,000 teeth in its lifetime the outer part of a great white shark's tooth is made up of hard and mineral Rich analid which is similar to the enamel on our teeth and is made up of fluorapatite a mix of fluoride and calcium bonded together fluorapatite is a very hard mineral so these teeth can withstand the crushing Force when biting prey and this crushing force is one of the strongest in the animal kingdom in 2008 a team of scientists conducted an experiment to determine the great white shark bite force using three-dimensional computer analysis of their jaw mechanics and while only theoretical their findings indicated that the largest white shark could exert a bite force of over 18,000 Newtons if their analysis is correct it would mean the great white shark has the second most powerful bite of any living animal after only the Orca however the saltwater crocodile is another contender in the mix for top bite force and has actually had its bite force directly measured at 16,40 Newtons But whichever animal is on top it's actually surprising that great white sharks are a contender at all because their skeleton including their jaw structure is made entirely of somewhat rubbery cartilage this cartilage is several orders of magnitude less stiff than bone this perhaps prevents the bite force of great whites from being even higher but for however much their cartilage skeleton May hold them back from an even stronger bite it makes up for in their Locomotion cartilage is strong and dense but it's not as heavy as bone so it reduces the weight sharks making it easier for them to swim at faster speeds with less energy being expelled and it's clear that they are top swimmers they can swim as fast as 50 kmph or 35 mph and have been known to migrate long distances from Hawaii to California and from South Africa to Australia their speed and endurance is thanks to their unique and surprising musculature generally fish have two types of muscle fibers white and red red muscle fibers are aerobic and sustain constant swimming whereas white muscles are anerobic and are primarily used for short bursts of Power with their huge migrations you might expect a great white shark to therefore have tons of red muscle but it's actually the opposite great white shark muscle is comprised of over 90% white muscle fiber this gives them an unparalleled ability to accelerate quickly while hunting ambushing their prey at high speeds but what about their long-distance travel how does such a low percentage of red muscle work for this unlike other fish whose red muscle fibers are situated just under the skin the red muscle fibers of great white sharks are located deep in the body the thickest part of the red muscle is also located near the dorsal fin which is the thickest part of the body this again seems to not make sense at first if the purpose of this muscle is sustained swimming why is it so far from the tail and close to the bending axis as counterintuitive as it might seem this placement of the red muscle allows for very efficient motion and is what gives the great white shark its swimming style called thundor swimming thunderform swimming generates power through the coddle fin rather than whole body undulation compare this to the swimming used by other fish these types of movement move the whole body which would be less efficient at High speeds but even with a buoyant skeleton and efficient Locomotion all this activity in fairly cold water might seem surprising considering most fish including most sharks are ectotherms that have a lower body temperature and move slower eat less and grow slower but when scientists started to measure the internal temperature of great white sharks they found something unexpected they placed one thermometer inside a shark's stomach and one on the outside of the shark to read the ambient water temperature and they found that even when the water temperature fluctuated and was quite cold the shark's stomach temperature stayed at around 26.2 de C this could only mean one thing that the great white shark was regulating its body temperature it is now understood that these sharks have an adaptation called Regional endothermy this is a type of warm-bloodedness that allows the shark to keep its critical regions like its swimming muscles stomach and Rin warm this does a few things for the shark it allows them to live in much colder water dive much deeper move much faster and it might even be the reason they are so enormous by unlocking a broader Niche and being able to hunt faster larger animals Regional endothermy may have been the thing to promote the true competitive superiority of great white sharks but with this endothermy comes a cost great white sharks are among the most energy demanding fish meaning they need to eat a lot to stay alive which brings us to the next question how does a shark decide what to attack and when we've all heard certain advice about how to avoid shark attacks don't swim at dawn or Dusk and whatever you do don't bleed in the water and we've all heard explanations as to why Surfers get bit that great white sharks have poor vision and mistake Surfers for sea lions or Turtles and if you're getting attacked punch it in the eye as best you can but really only some of this is true because what really motivates a great white shark attack is different from everything we've been told and the reality of it has been revealed by Decades of research in one specific and spectacular geographic location the Falon Islands in Northern California these islands are a rich feeding ground for great whites and though it's only 30 Mi west of San Francisco Surfers and swimmers know to stay far away seals and sea lions are abundant here and these are a great white's favorite prey the first thing the researchers stationed on the islands noticed was that great white sharks hunted during daylight hours which is different from how most other sharks hunt so the argument that avoiding swimming at dawn or dusk will prevent a great white shark from taking a nibble on you is not exactly helpful though might still be smart for other reasons at first this surprised scientists for a long time sharks were thought to have poor vision with a grainy and monochromatic view of the world enabled by what scientists thought was exclusively rods in their eyes rods are useful for detecting contrast and movement and animals who live in lowlight settings have an abundance of them cones on the other hand discern detail and require a well-lit environment and for a while these were believed to not exist in sharks but in 1985 scientists realized that the white shark does have cones and that their rod to Cone ratio was different from that of almost any other shark the moderately deep dwelling smooth Dogfish has a rod to Cone ratio of about 100 to1 the more shallow water lemon shark has a ratio of about 12:1 but in the white shark the rod to Cone ratio is about 4 to 1 great whites hunt in the daytime because they have excellent color vision and are primarily visual Hunters but this is not to say that white sharks can only see during the day just like cats and other nocturnal animals you see when you shine your flashlight in the woods at night sharks have a reflective layer behind their retina called the tapetum lucidum this structure greatly increases the photos sensitivity of the eyes in low light conditions so much so that great whites can likely see By Starlight alone and this brings us to the next myth about great white sharks that they mistake Surfers for turtles or sea lions but with their excellent Vision a great white likely knows with certainty when it's got a prey animal like a sea lion in its field of view so why do sharks sometimes attack humans and how do they choose what to attack and what to eat at all the researchers at the Falon Islands got a glimpse of this when on their watch a commercial scuba diver was attacked by a great white 200 M from Shore the shark swam up from underneath seized him carried him pulled him down for several seconds and then suddenly let him go and swam off the man was severely injured but survived this pattern is similar to other great white shark attacks on humans they bite but then they release but why don't sharks want to eat us we seem like an easy enough Target a hint emerges by looking at other animals sharks attack but don't eat the researchers at the Falon Islands noticed in one instance a shark seized a brown pelican totally mangled it and disabled it however the shark just left it there to die and never ate it they've also noticed dozens of dead sea otters that wash up on shore intact but with fragments of great white shark teeth embedded in them what is the connection between humans pelicans and sea otters we are all mostly made of muscle whereas the preferred prey of great white sharks like seals and whales are mostly composed of fat we've already established that great whites are very energy demanding fish because of their endothermic nature but to be so picky as to totally abandon muscly meals for fatty ones seems extreme but it turns out they need fatty meals for more than just their energy demanding metabolism and movement they need all that energy to grow and grow fast adult white sharks increase their body length by more than 5% per year this growth rate is three times higher than the moo shark another large predatory shark from the same family so when a great white nibbles on a human it's simply gaining information about whether you have enough blubber to be worth their while and for the animals that are worth a great white shark's while well that really sucks for them because the way a great white shark hunts is actually more horrific than I ever quite realized and it's a little different depending on which prey it's going after fair warning this is where the queasiness might set in when a great white shark attacks a sea lion it usually starts with an explosive Splash this initial strike often takes a chunk out of the sea lion but sometimes it is able to escape the researchers at the Falon Islands recorded 75% of sea lions surviving the initial strike but their escape is temporary the white shark will chase down the injured animal and recapture them it takes another bite but then lets it Go the animal will slowly bleed out and die later its body will float to the surface and only then will the shark eat it a great white's approach with a seal is slightly different the first bite that's so explosive when hunting a sea lion is usually invisible when hunting a seal it happens under the water the way researchers identify a seal attack is a large Blood Stained area of water then the blood stain elongates indicating the shark is carrying the seal sometimes great distances underwater once the seal is no longer bleeding the shark will allow it to float to the surface and only then will the shark eat it both of these methods of hunting appear to be almost ritualistic biting releasing dragging and most notably of all exsanguinating in almost every instance the researchers observed the the cause of death of the prey animal was blood loss and the Sharks seem to always wait sometimes for quite a while for nearly all the blood to be gone researchers don't fully understand why they do this but their best guess is that the shark doesn't want to eat prey that is still thrashing because they don't want to get any injuries so they let their prey die a slow death and wait to make sure they are super dead before eating the most heinous method of murder all because the Sharks don't to get any boo boos but great white shark rituals go even further revealing that great whites May in fact be capable of communicating with each other to a remarkable degree once a shark kills a prey animal like a seal it often floats at the surface for a while before being eaten but if there are multiple sharks in the area they are all going to want that tasty meal and the decision of who gets to eat it is decided in a surprising ritual the Sharks don't fight over the the food instead they participate in a threatening display of tail slapping at the surface splashing in the direction of the other sharks as many times and as forcefully as possible the shark who manages more tail slaps is the winner it's surprising that an animal so formidable wouldn't just fight over the prey but this sort of holds up with their other Behavior they really are boo boo avoidant but when the boo boos in question are having your face spit off by your opponent it makes sense that great white sharks would evolve a less violent but still dominance-based way to communicate and claim prey and this backs up one of the main pieces of advice we get if a shark is attacking you to punch them in the face these murder guys are kind of delicate and many Surfers and divers have reported that a biting shark left them alone after a strong Boop to the snoot and as much as I'm joking around about this great whites really are pretty sensitive a jab to the face probably does really hurt them due to tons of nerve endings and sensitive tissue there and though delicate these tissues are what make the Sharks such Keen hunters in particular their nose is the source of their Electro reception abilities if you look closely this area is full of tiny little black dots these are pores called ampl of laurenzini filled with an electrically conductive jelly the bottoms of the pores are lined with hairlike cells called cyia these cyia respond to changes in nearby electrical currents transported by the jelly which trigger nerves in the shark's brain which tells them something alive is near by but this Electro sensory ability only works from about 1 M away while the shark is locking onto its Target in the final moments before attack to sense prey at longer distances they use their incredibly acute sense of smell great white sharks have the largest olfactory bulb among sharks its relative mass compared to the rest of of its brain is 18% and a keen sense of smell makes sense when you consider how stinky a great white's preferred prey is if you've ever been to a beach or a pier where sea lions are hanging out you'll know what I mean odors from stinky sea lions or decaying whale carcasses create scent trails that are carried by the tides and the currents sharks might be able to follow these trails with great Precision a huge benefit if a blubbery meal is the reward but the claim that a great white shark can smell a drop of your blood from a mile away the jury's still out on this one I can't find a single reputable source that has done an experiment that tests how far away a great white shark can smell a drop of blood I personally still wouldn't jump into the ocean with an open wound but if you get a scratch while surfing you probably don't need to worry about it for so many reasons we don't need to worry about great white shark attacks at all great whites are simply not the maneaters they they've been portrayed to be we can see how risk avoidant they are how much they don't want to get injured how they communicate gently they are complex and sensitive animals and our attempts to force them into a box figuratively and also quite literally has only done them harm the first aquarium to attempt holding a great white shark was marine land of the Pacific in 1955 and the shark died in less than 24 hours when they tried again in 1960 the shark barely made it 2 days but this failer isn't unique to marine land for decades multiple aquariums attempted to hold great white sharks in their display tanks marine land of Florida SeaWorld of San Diego the steinhart aquarium and other aquariums all tried holding great white sharks but they either died or had to be released what was going on if so many facilities failed to keep great white sharks alive for more than a few days clearly something about captivity just doesn't work for these animals researchers have speculated about a couple of possible causes first the Sharks might have been ill before they were even captured in some cases they've been hooked by fishing nets immediately before being transported to an aquarium and if a great white shark isn't constantly swimming it can't get enough oxygen and is on borrowed time another hypothesis is that their Electro reception skill interferes with their ability to sense the glass of the tank meaning they're constantly bashing into the walls these sharks are also used to traveling vast distances and being stuck in even a large tank is still a huge shift in their ability to roam far and wide they're also used to hunting live food not eating dead fish handouts the mree Bay Aquarium therefore decided to take a different approach from 2004 to 2011 they brought in only young of the Year white sharks the scientific term for fish that haven't yet reached one year of age over that period of time they brought six sharks into captivity four did fairly well and remained on display between 70 and 198 days so what went right and what went wrong for these young sharks first there was their size and age the Sharks ranged in size from 137 to 164 cm and weighed between 25 and 47 kg much smaller than full grown adults they were also transported in stages first they were brought to a deep ocean pen off Malibu to allow them to recover from the stress of being captured they stayed in the ocean pen for 10 to 25 days or until they started feeding regularly again and were deemed healthy enough for transport from the pen they were moved into a transport tank on a ride that lasted between 5 and 7 and 1/2 hours once they arrived at Monterey Bay Aquarium they were placed in the 3.8 million L outer bay exhibit that holds pelagic fishes like blue fin and yellow fin Tunas as well as other shark species the four sharks who did do well in captivity ate regularly and were fed on a diet of fish like Pacific mackerel but two of them started displaying predatory behavior during the final weeks on display one shark fatally attacked two soupin sharks and they both chased scalloped hammerhead sharks and galpagos sharks no surprise both these sharks were released when they started chomping on the other animals in the exhibit but what about the two sharks who didn't do well one just never fed regularly so staff released it after 11 days the other fed somewhat regularly but also started bumping into the walls of the enclosure it showed signs of developing an infection ction and stopped eating so the montre Bay Aquarium released it after 55 days of captivity and fitted it with a tag unfortunately the tag showed it died almost immediately the researchers never recovered its body so an autopsy wasn't possible but they speculated that its death could have been caused by an attack from a large predator or from an injury when the acoustic tag was being implanted the third possible cause of death is a mouthful but as the report reads an irreversible Cascade of metabolic aberration associated with an acidbase imbalance caused by the cumulative effects of extraction from exhibit transport to Southern California pre-release handling sampling tagging and transport to the actual release location in other words being brought into captivity is what triggered its death imagine being a huge Predator with the entire ocean at your disposal then suddenly you're yed out by some hairless Apes put in a weird moving tank then dropped in a larger but still limited tank if there's anything surprising here it's that the Monterey Bay Aquarium succeeded in holding these animals in captivity for any length of time from start to finish the biology of great white sharks shows us that it is not us who need to fear the Sharks but the other way around I definitely still don't want to take on a great white in a 1 V one battle but it's not hard to see that despite our lack of terrifying jaws of death we really are the animal in the world that holds all the power great white sharks are delicate sophisticated animals who deserve as much reverence and respect as any of the charismatic ocean animals we all care so much about and when it comes to the chances of being bit there's a lot of stats floating around out there some say a person's chance of getting attacked by a great white shark is 1 in 11.5 million others say it's one in 40,000 there are a lot of different calculations going on here what's the real number the answer lies in an understanding of probability and surprisingly there's a free and easy way to learn about exactly this on brilliant brilliant is the best way to learn math data science and computer science interactively and they have a brand new course called intro to probability which teaches you to analyze real world data to calculate the probability of many different kinds of events There are 16 lessons that will allow you to understand probability by manipulating visually Iz ations to understand the likelihood of different scenarios I love the interactivity of this the sliders and buttons that allow me to test my understanding as I go along this is so much more engaging and so much more effective for me than rigid textbooks and classroom settings with what I learned on brilliant and after doing some more digging I came to understand the shark statistics a bit better the one in 40,000 chance of being bitten by a great white comes from data about people engaging in a specific activity in a specific place people doing offshore surf Sports off the southern coast of Australia the 1 in 11.5 million stat comes from a different subset of people people who go to the beach in the United States these are very different scenarios and thus very different numbers by digging into the data behind the stats we see thrown around all the time we can avoid being freaked out and instead just get to the truth brilliant has thousands of lessons like this from foundational and advanced math to AI data science neural networks and more that will help you learn about topics that we hear about all the time but may not fully understand it's a great way to become educated about the world in a very real and very meaningful way so to better learn how to confidently navigate this world of overwhelming numbers and to try everything brilliant has to offer free for a full 30 days visit brilliant.org /re science or click on the link in the description the first 200 people will get 20% off brilliant's annual premium subscription and every sign up helps this channel
