"Basking in sunlight a sperm whale rests after its journey from the black depths of the ocean" "Sperm whales are the deepest diving of all mammals and can spend up to ninety minutes on the sea floor hunting giant squid and other bottom dwellers" "Like mammals on land all whales and their dolphin cousins are warm-blooded and need to breathe air" "So, how have whales adapted terrestrial organs to a life at sea so successfully?" "And what prompted their ancestors to move from the land to the oceans?" "WHALES" "The blue whale is the largest animal ever to have inhabited the planet" "Growing up to one hundred feet and weighing as much as one hundred and ninety tons or three hundred eighty thousand pounds" "It is also extremely rare" "Only its need to breathe allows us a fleeting glimpse of its legendary bulk" "The blue whale belongs to the order Cetacea which includes the great whales and their much smaller relations porpoises and dolphins" "The smallest of dolphins is a fraction of the size of a blue whale's fluke" "At a little over four feet" "Hector's dolphins are also rare" "Their range is limited to a few coastal areas of New Zealand where they hunt for fish near the surface" "As mammals whales use lungs to breathe air rather than gills to breathe water" "Whale's lungs are relatively small but they are remarkably efficient" "When a whale surfaces it can replace up to ninety percent of the air in its lungs in just a few seconds" "But this efficiency alone cannot account for its ability to stay underwater in some species, for as long as two hours" "A diving whale descends with almost half its total oxygen stored in the muscles where it is slowly released overtime" "The whale uses this oxygen with great economy" "Only essential organs, such as the brain are supplied while others go into oxygen debt until the animal returns to the surface" "But the deep diving sperm whale needs more than these adaptations its bulbous head contains the so called spermaceti organ" "Filled with a complex mixture of fats and waxes one of the organ's functions is almost certainly to act as a biological ballast tank" "When water is drawn into the huge nasal passages the mixture cools and hardens helping the whale to descend rapidly" "The process is reversed by ejecting the water and pumping warm blood through the organ to liquefy the wax" "All whales have bones that are light and filled with oil which acts as an aid to buoyancy" "It's also a vital energy reserve during periods of fasting" "Whales are powerful swimmers with tail flukes that are horizontal rather than vertical, as in fish" "The flukes are boneless and consists of strong, fibrous tissue" "Powered by a pair of massive muscle blocks forward of the flukes whales cruise at six miles an hour with the fastest reported speed in excess of forty miles an hour" "Unlike cold-blooded fish whales need to stay warm in frigid waters" "Blubber, a layer of fat up to twenty inches thick acts as thermal insulation" "But whales can also actively conserve heat using warm blood pumped from the heart" "Areas with little or no blubber such as the head and flukes operate a heat exchange system" "Cooled blood in the extremities is partly heated as it passes by the warmer blood" "A vital adaptation because heat from a body immersed in water is lost around twenty-five times faster than in air" "The very cold waters, thousands of feet below the surface are the natural hunting grounds of the sperm whale" "Sperm whales are the largest of the toothed whales part of the group that includes the orca or killer whale" "With up to ten or twelve pairs of cone-shaped teeth orcas can threaten even the largest prey" "And it's the only whale that can kill other whales" "Dolphins also belong to the toothed whale group and feed on fast moving fish and squid" "Dolphins have even moved into some large rivers where they have become highly specialized" "Primitive river dolphins like the Amazon Buto have limited eyesight and use echolocation to find their prey in murky waters" "Echolocation or sonar has only been used by humans since World War I I. ." "... butevolvedintoothedwhalesand dolphins over millions of years" "Dolphins emit short pulses of ultrasonic sound that bounce off objects producing echoes which the animal uses to create sound pictures of its surroundings" "Among the constantly shifting ice floes and channels of the Arctic seas the ability to navigate beyond the limits of vision is vital to survival" "Another toothed whale, the beluga. ." "... hasextraordinarysensoryskills including a highly tuned sonar navigation system" "Complex muscles above the jaw focus a beam of sound that produces a very precise image of its surroundings" "enabling the whale to plot a safe route through channels under the ice" "The belugas may descend to a thousand feet to echolocate scarce breathing holes in the ice" "Their acute hearing also helps them evade predatory polar bears" "The largest whales and therefore the largest animals on Earth don't have teeth at all and feed on the world's smallest animals" "These zooplankton in turn feed on minute sea plants called phytoplankton" "Floating crustaceans known as krill are among the larger zooplankton" "During the summer months their swarms form concentrations dense enough to discolor surface waters for many square miles" "These super swarms have been estimated to weigh over two million tons" "A blue whale feeding on krill may take in one hundred thirty pounds in one mouthful and up to four tons a day in the richest Antarctic seas" "ln a unique adaptation some whales evolved baleen plates as a simple replacement to teeth enabling them to harvest these swarms" "Rows of these plates are suspended from ridges in the upper jaw" "Baleen whales feed by simply opening their mouths to take in both prey and water" "By closing their mouths and raising up the tongue the water is expelled through the baleen plates filtering out the food" "Baleen itself is made of keratin like hair and fingernails" "Fromhundredsof plateshang countless hairlike fibers that can filter the vast quantities of food" "Gray whales, the most primitive of the toothless whales evolved thick, bristly baleen to rake the seabed dislodging crustaceans embedded in the sand" "Many whales spend most of their lives feeding but the oceans do not contain endless supplies" "Off the coast of Baja, California blue and fin whales hunt for food" "ln the summer months the waters near the coast are especially plentiful and so they and other whales congregate in large numbers to cruise among the dense shoals of fish" "The whales' activities incite a feeding frenzy among pelicans and other sea birds" "Fin whales feed by lunging moving rapidly sideways through shoals of prey with mouths open" "Expandable throat pleats increase the volume of water and therefore the amount of food taken in in a single lunge" "Fin whales grow to over seventy feet on a relatively small range of foods that include krill squid and some small fish" "Pelicans capitalize on the havoc wrought by the feeding fin whales" "Large whales also require enormous amounts of food because they need to build up reserves for the less productive winter season" "Humpbacks cooperate to harvest the sea using a skillfully woven fishing net to encircle their prey" "Swimming well below the surface they weave a net by forcing bubbles out through their blowholes by moving in a spiral beneath a shoal of fish" "The bubbles drive the fish towards the center of the net" "Surging towards the surface in unison the humpbacks form an inescapable phalanx of gaping mouths" "Orcas or killer whales cooperate in a different way" "Orcas can be aggressive intelligent predators" "Here they deliberately beach themselves to capture young sea lions" "Shoreline feeding has been passed down through the generations" "Adults showing their young how to achieve the best results" "This technique echoes the moment in evolutionary time when the land bound ancestors of all whales first became sea mammals" "At that time fifty-five million years ago the drifting continents were changing the face of the Earth" "India moved north to collide with Asia forming the massive heights of the Himalayas from what was the floor of the ancient Tethay Sea" "The remaining water which today forms the Mediterranean became shallow and more saline fueling an explosion of sea life" "On the edges of this remnant sea in a primeval world of tropical swamps and estuaries lived a group of animals known as Creodonts" "A sub-group of the Creodonts known as the Mesonychids hunted close to the water" "Some ate plants, but others were opportunistic scavengers carnivores that fed on dead fish washed up by the tide" "Eventually these carnivores hunted exclusively along the tide line entering the surf to capture dead or dying prey" "Within a few million years they had developed into semi-aquatic creatures feeding wholly in the sea" "... thefirstprimitivewhales" "ln the last few decades scientists have gradually uncovered the mystery. ." "... ofhowalandmammalreturned to the sea" "Near Santa Barbara on the Californian coast new finds like this twelve million year old skull of a whale are adding to an emerging picture of how whales evolved" "At this stage, scientists Louise Kearin and Lawrence Barnes are not sure exactly what is inside the rock" "But painstaking excavation will eventually allow them to place this animal within a complex evolutionary jigsaw" "One that is already relatively complete" "The whale story begins with the amphibious animal that evolved from Mesonychids" "Pachocetus, the earliest known whale still had four limbs as it explored its aquatic environment fifty million years ago" "Fromthenon ,theyevolvedrapidly" "Ambliocetus had large hind feet clearly adapted for swimming" "Then later Rotocetus evolved a feature that enabled them to venture further from the land" "The tail vertebrae detached from each other allowing the tail to move up and down for propulsion" "Ziggarisa lived around forty million years ago lt had a flexible forelimb but the hind limb had now almost disappeared" "Ziggarisa showed another important adaptation" "The blowhole moved toward the top of the head" "ln just over ten million years the early whales had left the land forever" "These primitive whales had teeth designed to grasp and shear but eventually they became modified to form long rows of sharp uniform teeth" "Today's toothed whales, dolphins orcas, and sperm whale are their descendants" "Around twenty-five million years ago the baleen whales evolved from a toothed ancestor" "Even today the fetuses of some baleen whales have remnants of teeth" "For a land mammal to have evolved into the creatures we see today such as this minke whale evolution had to be chemical as well as physical" "Kidneys became specialized to deal with excess salt" "Fluids covered the eyes to protect them from the saline environment" "No other mammal has a covering so sleek" "These small adjustments taken together transformed medium-sized land mammals into huge sea creatures" "At just under one hundred feet long a Boeing 7 37 is shorter than the largest recorded blue whale" "A blue whale's heart is the size of a Volkswagen" "And the whale itself is six times heavier than the plane" "Their immense size meant that the great whales were able to fuel a hemisphere" "Whale oil lit the continents for many centuries and later lubricated the machines of the lndustrial Age" "European and American whalers made huge profits unaware they were hunting their quarry to the edge of extinction" "Whales were not only killed for their blubber" "The strong and flexible baleen from their mouths was used in a range of domestic products from corsets to umbrellas" "Decade after decade tens of thousands of whales were slaughtered to satisfy the needs of a burgeoning human population" "Herman Melville's story of Moby Dick the mythic great white sperm whale told of high adventure, obsession and an existence fraught with danger" "By the mid-1 9th Century whaling methods had changed little from earlier days of subsistence hunting lt was still an intimate struggle between men and whales" "A disaster was always looming" "By the turn of the 20th Century even the biggest whales were pursued in the polar regions and processed in vast factories. ." "... yieldinghandsomeprofitsto the new whaling magnates" "Most highly prized was the fine oily wax from the head of the sperm whale to be used to oil precision machinery" "But as catching methods changed so did the use of the whales" "Whale oil no longer lubricated the world and carcasses were rendered down for soap margarine, fertilizers, cosmetics and to provide food for pets and farm animals" ""Thank you, Ladies and Gentlemen and welcome to Shamu Stadium."" "Human attitudes have changed significantly since mass whaling ended" "And whales now hold a special place in our collective conscience" ""Come on, folks" "Now who wants to see some magic?"" "We've come to recognize that whales are highly intelligent capable of sophisticated interaction with other species like ourselves and able to imitate and learn" "Whales are even adaptable and successful in some pretty unusual situations" "Whales and dolphins are essentially social animals" "For some, like these dolphins belonging to a large group. ." "... hasclearbenefitsforsurvival" "The chances of finding food are increased since the group can range far wider than one individual" "Collective defense against predators is more likely to succeed and grouping helps bring individuals together for breeding" "Dolphins can congregate in the hundreds" "Their schools are fluid with individuals leaving to join other groups but with a corps of members that stays together" "The much larger whales rarely school and the closest bond is probably between a solitary mother and calf" "Baleen whales come together at feeding grounds and to mate but then disperse rapidly" "However, sperm whales the largest of the toothed whales do group together in pods in warmer waters" "Females form the corps of the pod which also consists of calves and juveniles of both sexes" "Sperm whale bulls spend most of the year alone hunting in colder waters" "But during the breeding season they join the pod forming a harem" "ln this rarely filmed display of strange and sensual behavior all the sperm whales in the pod form a knot of writhing bodies" "lts purpose is unclear but it may be a means of reinforcing social bonds within the pod" "It may also have a more directly sexual function since this encounter seemed to stimulate the immature males" "Pilot whales also live in tightly knit groups but they are often led by a single older female" "Strong social bonds like these may hold a clue to one of the most perplexing mysteries about whales their apparently deliberate strandings on shore" "Evidence from stranding sites suggest that some animals had parasitic infestations of the ear and brain to such a degree that it may have caused disorientation" "An infected dominant female could easily lead her entire group into dangerously shallow waters" "But not all scientists agree that these infestations are the only answer" "Others point to magnetite particles found in the brain of several species that may be acting as an internal compass" "These particles may detect the Earth's magnetic field which originates deep within the planet and draws an unseen grid across the globe" "If whales are using this geo-magnetic information to navigate it's possible that this system breaks down leading them into shallow water traps" "Some whales look like floating reefs" "They're a place in the vastness of the sea for parasites to call home" "Whales are host to many kinds of parasites" "Barnacles that attach themselves to the skin do little harm but other creatures feed on the whale's flesh" "Whale lice have claws that can cling onto a rapidly moving animal and jaws designed to pierce its flesh" "The lice may cause only minor irritation but the whale's attempts to dislodge them can be spectacular" "Spring arrives in the Arctic and as the ice recedes it's a time for renewal" "Beluga whales move en masse from the ocean to the newly reopened river inlets" "All whales shed skin and parasites during their lives but belugas are the only whales that migrate to certain areas in the Arctic specifically to molt their skin" "They wait for the tide to enter the fresh water shallows where a gravel and sand river bed will help them remove old skin" "During the year a coat of yellow-green algae builds up on the upper body and this, too, will be shed" "Small lead groups of beluga enter the river mouth even though they are vulnerable to polar bears in such shallow waters" "As the tide peaks, hundreds of whales begin rubbing and scratching against the river bed and each other" "After a few days they will return to their feeding grounds in the open sea scarred in some places but parasite free and with sleek white skin" "With the evolution of sociability among whales came the development of highly sophisticated communication" "Whales vocalize almost continuously and produce a range of sounds that is remarkably diverse" "Underwater, sound travels four times faster and much further. ." "... thanitdoesinair" "All whales need to emit sounds over large distances for identification and to locate other whales in the wilderness of the sea" "ln this way, whales constantly send and receive information about sex and activity" "Sperm whales use a series of clicks known as codas" "It appears that one whale will call and another will answer with exactly the same coda" "This will be repeated on different occasions by different individuals in the group" "ln other areas of the oceans, populations of sperm whales have different codas indicating the existence of dialects within the sperm whale language" "One of the more remarkable features of whale communication is the plaintive alluring song of a lone humpback whale" "ln an attempt to attract a mate a male may sing for more than twenty-four hours with only a few short breaks to breathe" "His song may last up to thirty-five minutes before being repeated" "A whale's song is quite clearly defined with a recognizable beginning middle and end" "lndividual songs have their own peculiarities their own syllables phrases and themes" "Sound is one way of attracting a mate" "However for a female narwhal living in icy Arctic waters sight takes precedence in the search for a suitable partner" "Male narwhals which grow to about fifteen feet have ivory tusks that are up to ten feet long" "Males joust with these elongated swords which are both weapons and symbols of dominance" "The successful competitor wins the right to mate with females" "The strongest male passing on its genes to future generations" "Among southern right whales male competition is intense" "The idea is not to be the first to mate, but the last" "Because southern right males have the largest testes on Earth each weighing close to half a ton the last male to mate not only deposits huge quantities of sperm but washes out that of the preceding males" "This gives his sperm the best chance to reach the female's egg" "Many whales migrate huge distances to mate" "But the master mariner is the gray whale its journey is the longest of any mammal. ." "... aneleventhousandmileroundtrip" "From October whales begin migrating south from the Bering Sea in Gulf of Alaska hugging the North American coastline down to the warm water lagoons of Baja California" "The annual migrations of gray whales are synchronized with their mating patterns" "Conception and birth always occur in these Baja waters because gestation periods last twelve months" "Calving every two years places enormous biological strain on those females that conceive regularly" "But the warm waters of tropical breeding grounds may help sustain both females and their newborns" "Twelve feet long and eighteen hundred pounds at birth a young humpback grows rapidly over several months nourished by a rich milk that contains up to fifty percent fat and protein" "Before it weans the young humpback may increase its weight by five times feeding on a hundred fifty gallons of milk each day" "Apart from the occasional snack a mother will not feed while nursing its young even though a huge amount of energy is used up to produce such a large offspring" "A mother must also protect its young from threats that can come from any direction" "To a pack of hungry killer whales any newborn whale is a tempting target" "Of course the greatest threat to all whales comes from another species of mammal altogether" "Humans began whaling during the first migrations from Siberia to the Americas" "These early settlers survived in a hostile environment by making full use of dead or stranded whales as a rich source of food oil and shelter" "Recognizing the whale's value they soon developed hunting techniques to keep themselves supplied for the long winter months" "Today, subsistence whaling is still part of life in the frozen North" "This narwhal will provide good eating for the weeks ahead" "The skin and blubber will be cut and dried providing food that is rich in Vitamin C" "ln earlier days the slower species that came close to the shore such as the bowhead and right whales were hunted in open boats using hand-crafted spears" "Most of the animal would have been used including dried bones used to construct frames for shelters" "The annual catch of whale populations was small and life in the Arctic remained relatively stable for many centuries until the coming of a new threat the commercial whalers" "But today the mass slaughter of the great whales is all but over" "Conservation groups fought long and hard to close the whaling stations but by the time mass whaling had ended over three-quarters of the world's population of great whales had been obliterated" "Communities that once depended on the whaling trade are now sustained by a new industry" "Whale Watching Eco-Tourism" "Even though many of the whales are protected as endangered species it may be a century or more before the most heavily hunted can recover" "One positive step came in 1 994 with the creation of a Southern sanctuary in the seas surrounding Antarctica a haven for eighty percent of the world's remaining great whales" "During the fifty million year odyssey myriad sea mammals evolved from a terrestrial creature that hunted the shores of ancient oceans" "They gradually lost those features that associated them with the land now spawning their young into the oceans" "where they would spend their entire lives" "Adaptations to new food sources created a mammal without teeth the baleen whale" "New ways evolved to navigate the immensity of the sea to dive to the bottom of the ocean and overcome the dangers of the deep" "They became social animals that now hunt together play together and call out across the ocean vastness" "THE END"