RISE OF THE GREAT WHITE SHARK - ANDY BRANDY CASAGRANDE IV - ABC4EXPLORE

[Music] it lurks at the margins of our world we're polar currents stir the deep ocean and sea creatures feed on its bounty [Music] how did the great white shark emerge millions of years ago to become one of the world's dominant predators [Music] [Music] out in the unending waters of the Pacific west of Mexico is a rocky remote outpost called isla Guadalupe [Music] a handful of visitors have traveled here to observe at close range one of nature's crowning achievements they do so from the protective confines of a steel cage rising up from the murky deep a dim figure appears moving quickly and effortlessly through its liquid universe [Music] a great white shark humans maybe the planets top predator but in the ocean its sharks had lured over the cycles of life and death [Music] we face this species with extreme caution [Music] they approached us drawn by the scent of bait our noisy technology or even the vibration of our beating hearts white sharks gather by the hundreds each year along the shores of Isla Guadalupe often swimming thousands of kilometers for several months each year this island plays host to tens of thousands of Guadalupe fur seals and California sea lions they haul out along steep shorelines to rest mate and bear their young from these rocky protected shallows they move out into deep waters to feed on fish that thrive in the cool nutrient-rich waters of the eastern Pacific they are joined by thousands of northern elephant seals once hunted to the verge of extinction their numbers have surged all along the western coast lines of North America including Guadalupe for a great white shark a successful elephant seal kill brings a huge reward adult males can grow to a weight of more than 2,000 kilograms we often see great white sharks in one-dimensional terms as indiscriminate killers ever in pursuit of food the truth is like us they each have their own personalities they can be bold or shy some are steady others erratic and unpredictable sharks are by nature curious especially when something new enters their realm [Music] in this case a camera that had been attached to a shark's dorsal fin sharks predate dinosaurs by several hundred million years [Music] their success is due to their ability to adapt to conditions in nearly every nook and cranny of the world's oceans it's also based on several major anatomical innovations with torpedo-shaped bodies powered by tail fins with long upper and lower lobes sharks are built for speed [Music] they move effortlessly through the water thanks to tooth like features called denticles that line their skin at just a tenth of a millimeter long these ridge line structures reduce drag by dissipating tiny Eddie's that form along the skin packed tightly together rows of denticles help seal out parasites while forming a concrete hard shield against strikes by other sharks [Music] the Sharks swimming motion is stabilized by a series of large fins along its sides top and bottom with skeletons made of cartilage rather than bone they have the flexibility to accelerate and change directions quickly predatory sharks cease their prey by lunging than extending their jaws out from the skull large sharks like the great white or the tiger then use their sharp teeth to dismember their prey with vicious side-to-side motions [Music] [Music] in the process their teeth can easily break or shatter [Music] a shark replaces them by constantly generating new rows of teeth that roll toward the front of its jaw Guadalupe Island off the coast of Mexico is just one of several major gathering spots for great white sharks here is another the rugged coastlines of southern Africa [Music] powerful ocean currents sweep near these shores drawing cool nutrient-rich waters from the polar ocean that fuels an explosion of sea life including thousands of Cape fur seals and the sharks that prey on them [Music] [Music] visitors come from around the world to witness one of the most dramatic events in the natural world a white shark rising out of the water with its kill for most of the year the seals feed offshore preying on schooling fish such as sardines anchovies mackerel as well as sea birds and even penguins as summer approaches a stream into dozens of coastal breeding sites one of the largest is nicknamed Seal Island just off Hout Bay Harbor isolation from the land and the rugged undersea terrain make it an ideal refuge for seals males haul out for about six weeks each year remaining on land to protect their harems while living off their fat reserves the females arrive pregnant having mated the previous year after giving birth they make regular forays back to the sea to hunt spending three to four days away then two to three back on land to nurse [Music] here the young can grow and learn to hunt close to the island these strong agile hunters have little to worry about out in the open ocean they are too nimble and spread out for predators like the great white to target them the danger zone is the realm in between where sharks wait and watch for seals coming and going moving out to sea there is safety in numbers this group heads for deep water as quickly as it can time is of the essence [Music] they swim in a low porpoise diving down to scan the waters below but the visibility here is limited the seals may not see what lurks below [Music] [Music] [Music] [Music] what separates the great white from all the other predatory sharks is its size an adult can grow to a length of over six meters and weigh a ton or more scientists once imagined that the great white is a scaled-down version of the largest shark discovered in the fossil record the giant tooth Megalodon with its blunt nose and stout jaw Megalodon was the most imposing shark of all time it lived from 23 to about 2.6 million years ago because shark skeletons made of cartilage dissolve quickly in ocean water scientists have been left to reconstruct megalodons history from circumstantial evidence that includes a few fossil backbone segments and teeth for comparison the largest great white tooth on record measures less than 3 inches long from the crown tip to the base of the root along one side Megalodon teeth grew to twice that size over seven inches long that corresponds to a body length of up to 19 meters and a weight perhaps exceeding 50 tons megalodon probably had a bite force of over 18 tons greater than the mighty Tyrannosaurus Rex it was not the only super predator terrorizing the seas Megalodon shared waters with the largest tooth trail ever [Music] Leviathan Mill Valley was named for the giant whale in Herman Melville's novel Moby Dick Leviathan was a distant relation of today's sperm whale with males growing to 16 metres long with a weight of around 45 tons [Music] the modern sperm whale is the ultimate diver able to descend thousands of meters into the deep with one row of teeth on its lower jaw it uses suction to catch its preferred prey squid [Music] Leviathan had much larger teeth arrayed on both lower and upper jaws like Megalodon it worked the oceans surface seizing small and medium-sized whales with its impressive bite these two super predators thrived in an age when mammals were diversifying throughout the Earth's oceans their world was shaped by changes that began tens of millions of years before the dinosaur age came to an end some 65 million years ago North and South America had not yet joined North Africa Europe and the Middle East were a fragmented network of islands and channels India then a large island was moving steadily toward Asia in this time called the Eocene epoch carbon dioxide a greenhouse gas that traps the solar radiation spiked at up to six or seven times today's levels Earth's atmosphere was warmer than today by at least four degrees Celsius tropical palms and crocodiles could be found in high northern latitudes polar oceans would have been as warm as the tropics are today these hothouse conditions would not last by around fifty million years ago the movement of land masses separated the arctic sea from the wider oceans it became a warm Dead Sea its surface capped by fresh water from rain and runoff from the land a fern-like plant called Izola took hold in a year's time it can draw as much as 15 tons of carbon dioxide per hectare from the air meanwhile as the Indian subcontinent began to plow into Asia the mighty Himalayan mountains rose up massive amounts of exposed rock interacted with rainfall in a process called weathering that true even more co2 from the atmosphere washing it into the sea by 30 million years ago the earth was dramatically cooler I said taken hold on the southern pole staying year after year until it formed a thick sheet a cold current now circled Antarctica drawing nutrients to the surface and fueling a global explosion of sea life large highly mobile sea creatures began to ply the oceans including hundreds of species of filter-feeding whales like the humpback today they roamed the seas in great numbers scooping up countless tons of plankton and tiny sea creatures for the giant predators Megalodon and Leviathan whales would have supported a dietary requirement of around 1,200 kilograms of food per day fossil evidence tells us that megalodons range-extended nearly into the polar regions they would likely have given birth in the tropics especially in vast shallow areas between North and South America by 20 million years ago with ice accumulating at the poles sea levels inevitably fell that allowed North and South America to join in the Isthmus of Panama a warm ocean current now began to flow up the coast of North America bringing storms moisture and sea ice to the Arctic that led to dramatic seasonal shifts in fish and other food sources larger whale species adapted by migrating seasonally between tropical and polar regions smaller whale species began to disappear and with them Megalodon [Music] at the same time whole new types of predators and prey began to appear scientists recently discovered the fossil remains of a creature similar to a large otter that lived in the Canadian Arctic some 23 million years ago because of its webbed feet and distinctive jaws and teeth scientists see it as an ancestor to modern pinnipeds this new class of nimble marine mammals sea lions seals and walruses thrived in the highly productive waters of polar and temperate oceans they developed external layers of blubber to insulate against the cold they were followed in turn by smaller and more nimble predators that included another tooth to whale the Orca in the fossil record the earliest known orcas date back to around 5.3 million years ago [Music] orcas moved freely between the northern and southern hemispheres from tropics to poles achieving a global distribution the Orca would share the ocean with another rising predator the great white shark [Music] at about half the size of an orca great whites generally swim alone or in loose associations while pursuing prey were scavenging a carcass [Music] because of the scarcity of fossil remains deciphering the evolution of any shark species can be tricky since white sharks appeared as early as 11 million years ago their teeth have often been found in association with pinniped remains that has led to speculation that the two evolved in a close association in response to a steadily cooling climate [Music] because of similarities in their teeth the white shark is now thought to be a close relative of this shark the Mako [Music] ranging from 2 to 5 meters mako sharks today are known for their sleek cylindrical bodies it can accelerate to speeds of up to 70 km/h with keen eyesight the make of zeroes in on fast-moving prey in the open ocean including swordfish tuna and other sharks the white shark and Mako are each part of a family of large fast-moving sharks found in oceans around the world called lamb mid or mackerel sharks they are known from muscular spindle shaped bodies that taper at both ends with prominent dorsal fins in the centre of the body [Music] they both employ countershading with a dark back and light underside to conceal them from prey above or below [Music] over millions of years great white ancestors began to specialize by targeting new types of energy rich pray the pinnipeds for a great white targeting seals in the cold currents of the southern ocean poses a basic challenge the body temperature of most sharks is the same as the surrounding water in warm tropical seas this allows them to make efficient use of calories consumed in colder waters their digestion muscle response and even brain activity slows way down a white shark can stay warm by swimming in the sunlight close to the surface and by eating in response its body temperature increases allowing muscles to work harder heart to beat stronger digestion to improve and rate of metabolism to increase to keep this up a white shark cannot afford to lose body heat to the surrounding oceans a typical shark's body is composed of about 85% muscle compared to around 40 percent in humans most of it is white muscle used to power quick movements and acceleration in lamb Ned sharks like the Mako or great white a band of red muscle lines the core of the body and gives the shark endurance over long migrations it also allows the shark to combat the cold these red muscles are surrounded by a web of veins and arteries called RIT a new ballet oxygen-depleted blood flowing out of the muscle is shown in blue as it flows outward toward the gills it gives up heat from metabolic activity to oxygen-rich blood flowing in in this way the shark recycles the heat generated in the red muscle and sends it to critical areas of the body like the brain and the eyes as it targets seals and other large animals the white shark is primarily a visual hunter decoding the interplay of shapes and shadows ahead it locks in on its prey from a distance often rising out of the water to see or to bite [Music] but vision is only part of its success like other sharks the great white is a wonder of highly integrated sensory and motor abilities in the murky medium of the ocean the white shark understands its world through an acute sense of smell it is said to detect one part per million of blood in seawater its sense of smell helps it to locate concentrations of prey estuaries for berthing or to identify rivals or potential mates [Music] the great white shark has one of the largest olfactory systems in the sea with two large bulbs nestled in its snout they are connected into a large frontal brain and behind them two large optical lobes complex folds allow it to pack in more neurons the complete brain of a mature great white measures about two feet in length extending down to the brainstem at the top of the spinal column it integrates a range of sensory apparatus tuned to the highly conductive properties of the ocean that includes tiny pores arrayed along its snout they open up into a series of jelly filled pockets known as ampullae of Lorenzini specialized nerve cells read the voltage flowing into each pore this allows a shark to detect electric signals even off by movements or even the heartbeat of prey [Music] sharks extend their sensory reach by picking up vibrations in their inner ear and with a sensing system that runs the length of their bodies called a lateral line [Music] vibrations pass into fluid-filled canals where they excite air like cells these cells move and sway with the vibrations transmitting the information to the brain [Music] as a shark follows an odor trail released by prey it may use its lateral line to hone in on vibrations produced by its swimming motions for great white sharks this battery of senses serves a larger mission to hunt reproduce and roam the ocean in one of the longest life spans in the animal kingdom among its larger tropical counterparts the tiger shark reaches sexual maturity at seven or eight years in a lifespan of almost 30 years the great hammerhead begins reproducing at eight or nine and may live 30 to 40 years great white sharks can live up to 70 years in a study of great whites in the western Atlantic males reached maturity at 26 years of age and females as late as 33 years one reason they grow so slowly is that their intestines are small and tightly folded that results in slower digestion and longer intervals between foraging in females a smaller intestine makes room for a larger uterus she can carry her pups long enough to grow to a meter and a half long before birth increasing their chances of survival so to a smaller intestine allows for an unusually large liver a white shark uses its liver to maintain buoyancy and as part of an impressive energy storage system and up to a third of its total body weight a white sharks liver can hold over 2,000 liters of liquid blubber from seals it draws on this source to maintain strength during migrations covering several thousand kilometers to learn more about the breeding and migratory patterns of white sharks scientists have been tracking them from gathering points such as muscle Bay in South Africa each year his Island attracts thousands of fur seals one study showed that younger sharks with less experience catching seals range over large areas on the hunt for concentrations of fish as they approach maturity the Sharks begin to develop well-defined territories around the island by mastering the nuances of topography currents and even seal routes these adults learn to hunt successfully while conserving their energy in general great whites spend only a few months each year in these cold waters before moving on from South Africa some have been tracked moving up into the Atlantic some had north up the coast of Namibia here about two-thirds of the total Cape fur seal population up to a million animals occupy a chain of rookeries still other sharks head east into the Indian Ocean one female named Nicole began her journey at Seal Island in Hout Bay over a period of 99 days she traveled all the way to the northwest coast of Australia she was spotted seven months later back near Seal Island one of the most mysterious of all white shark routes was documented in the Pacific after a season hunting elephant seals white sharks depart the coast of northern California for the open sea one 5th end up in Hawaii perhaps drawn by humpback whales that give birth there the remaining 80% come together with sharks from Guadalupe Island in a wide open region known as the shark cafe given the large population of sperm whales in these deep waters it could be the sharks are attracted by an abundance of squid or by the whales themselves [Music] there may be another explanation off the coast of San Diego California fishing boats have reported scooping up an unusual number of white shark pups in the month of August given that white shark females carry their young for 12 to 18 months that means they would have made it during their time in the shark cafe [Music] from there the females eventually make their way to the tropical estuaries where they give birth [Music] citizens and scientists are coming in increasing numbers to places like Guadalupe Island to see and experience the world of the white shark [Music] they are part of a shifting balance in the way we see these magnificent creatures [Music] in the United States the shift dates back to the passage of the marine mammals act in the 1970s a time when the movie Jaws terrified a generation of beachgoers [Music] ironically off the coast of Massachusetts where the movie was filmed there were few sharks to be found that's because decades of hunting had reduced their main prey the gray seal to just a few dozen individuals along the beaches and lagoons of Cape Cod wildlife officials estimate there are now 30 to 50,000 grey seals they come ashore at low tide hauling out on sandbars and beaches or lingering in shallow estuaries as the tide comes in they move out to sea to feed in deep offshore waters the white sharks have taken notice of this growing bounty and have returned to their old stomping grounds great whites too are protected by US federal laws and by the Convention on International trade in endangered species or sight ease it's illegal to hunt them these protections are part of a broader effort to coexist with the natural scene here beachgoers are warned stay in shallow water and if there are seals in the water stay ashore just beyond the surf all along the coastline you can expect to find great white sharks on patrol that's also where you'll find Greg skomal and researchers with the Atlantic white shark Conservancy a spotter plane flies overhead looking for sharks silhouettes against the sandy shallows skomal and his team locate the shark and close in quickly [Music] there is no need to bait a shark to the boat the team simply slides up behind it for some they jab a device into the thick skin on its back it emits beeps that allow a network of listening stations to record the Sharks comings and goings the team attempts to photograph them up close with a camera mounted on a pole the idea is to capture identifying marks like scratches or lesions to help keep track of the individuals that come here [Music] the team wants to know how long the Sharks stay and where they go along the shoreline [Music] the marks also amount to a record of life experiences battles with other sharks mating scars health age and even personality he wouldn't let it go that sucker had scars screeched on its face came right up to the camera kept kept grabbing it wouldn't let it go and ripped it right off the pole and this this one had a clear attitude the Sharks they find here are nearly all around four meters in length they have to be this large to kill gray seals which often weigh more than 200 kilograms the seals know how far that can go from the beach the sharks won't move into shallow water for fear the surf could drag them ashore if a seal wanders out it had better be alert [Music] white sharks are ever opportunistic a whale carcass brings a sudden bounty [Music] [Music] four great white sharks the seal populations along Cape Cod are a focal point to a larger seasonal pattern satellite tracking devices attached by this team show that when the seals disperse in winter the Sharks head south most stay along the continental shelf where food is abundant a few head out to sea and slowly make their way back in time for the return of the seals the efforts of these scientists to understand and preserve the great white shark come at a crucial moment in its long history the public increasingly accepts the sharks as part of a larger natural scene in harmony with itself and with us the scientists report there is even a growing appetite for information about individual sharks including their life histories most are inclined to respect the realm beyond the surf where the Sharks are on patrol the great white shark evolved over ten million years ago from ancestors going back hundreds of millions of years the basic form of the shark it's sleek and flexible shape large fins and powerful tail has hardly changed in all that time a testament to its enduring success increasingly we measure our own success on this planet by our efforts to preserve creatures like the great white shark as well as the global ecosystems upon which they and we dependent [Music] [Music] you you

Channel: Andy Brandy Casagrande IV

Views: 1,210,164

Rating: 4.6388497 out of 5

Keywords: ABC4EXPLORE, ANDY, BRANDY, CASAGRANDE, IV, SHARKS, UNDERWATER, CINEMATOGRAPHY, CREATE, INSPIRE, EMPOWER

Id: 3QQLguXB5Cg

Length: 49min 12sec (2952 seconds)

Published: Thu Nov 08 2018