Ocean Giants

Page 1

GIANT LIVES

Chapter Two

BLUE WHALE

Balaenoptera musculus

Only in the vastness of the ocean could there live the largest creature on earth. The blue whale. Before commercial whaling 300,00 blue whales cruised the oceans. Today less than 10,000 remain. We know almost nothing of their lives and for years assumed that like the other great whales they migrated to cold rich seas to feed.

approach like southern right whales and not friendly like humpback whales. They are elusive and perfectly streamlined blues are one of the fastest ocean giants powering along at over 30 miles an hour. The largest creature in the ocean feeds almost exclusively on one of the smallest, krill. A crustacean just a few inches long Krill are normally found in cold polar seas.

Blue whales are the largest animals ever to have lived, bigger even than the largest of the dinosaurs. These jumbo-jet-sized giants inhabit the open ocean, where they are found most frequently along the continental shelf edges and near polar ice. They are so big that a blue whale’s blood vessels are wide enough for a human to swim through. A single calf is produced every two to three years, and from birth each calf consumes up to 50 gallons of milk every single day, leading to a colossal weight gain of 90 kilograms per day in its ÄYZ[ `LHY VM SPML )S\L ^OHSLZ HYL UV[ LHZ` [V

Recently Scientists have discovered that along the Sri Lanken coastline unusual condiitions allow kirll to thrive in tropical waters. The upwelling of cold nutrient-rich water is unusual for the tropics but appears to contain the perfect food for blue whales. The Indian Ocean blue whales are unique as they live there all year round. The blue whales feed by diving KLLW KV^U HUK ÄUK KLUZL WH[JOLZ VM RYPSS and lunge-feed through them. They dive to 600 feet below where the krill are hiding in the gloom. The whale then powers up through the swarm gulping its own body weight of water

05

GIANT LIVES

The Blue Whale is the largest animal that has ever lived on planet Earth.

BLUE WHALE

06

Length - 32 m Wieght - 200 Tons (Max.) Type - Baleen LIfe span - 80~90 years Food - Krill

07

GIANT LIVES

into its ballooning throat It then strains out the U\[YP[PV\Z RYPSS [OYV\NO P[Z ÄUL TLZO VM IHSLLU Each lunge requires huge effort but if you have a mouth as big as a blue whale’s you can catch so much food that the whole process becomes L_[YHVYKPUHYPS` LMÄJPLU[ Their size is the secret of their success. Pumped up on tonnes of krill blue whales can grow as long as a jetliner weighing almost 200 tonnes twice the size of the largest dinosaur. Worryingly the blue’s giant size and its giant appetite are now putting it at risk. We know that climate change is occurring and that in places like Antarctica the temperatures have skyrocketed. We also know that krill has started to decrease and when you don’t have enough food blue whales are going to have trouble surviving

So as climate change happens as krill starts to be depleted blue-whale survival could be in jeopardy. Blue whales are still endangered but they are recovering slowly For their recovery to continue it’s not just the whales themselves that will need protection. For their recovery to continue it’s not just the whales themselves that will need protection but the seas and the other creatures they depend on. We may have missed the chance to live with the great dinosaurs of the past but we do have the good fortune to be sharing our time with the largest creatures that ever lived these THNUPÄJLU[ VJLHU NPHU[Z

BLUE WHALE

08

HOW BIG IS BIG?

Comparing Blue whales length and weight

ONE

Blue Whale weighing 200 tonnes.

Would be the equivalent to...

32M 15M 6M

Full sized Blue whale can reach to a staggering 32 metres long, this makes it the biggest animal ever!

Even a fully grown humpback whale is dwarfed by the mighty Blue whale.

A large female Great White Shark measures 6 metres which looks small when compared to the Blue whale.

2667 40 OR

Humans each weighing 70 Kg.

Elephants each weighing 5 tonnes.

SOUTHERN RIGHT WALES Eubalaena australis

A southern right whale’s head measures one third of its total length. It is one of the easiest whales to identify as the enormous head is also covered in white-coloured outgrowths of tough skin. These callosities form a unique WH[[LYU VU LHJO ^OHSL SPRL ÄUNLYWYPU[Z PU humans. Courtship and mating is both tender and graceful, without any animosity between males mating with the same female. Females calve once every three years, giving birth to a weighty 1,500kg calf. Despite their great size, the young are brought up on a diet of high-fat milk and remain in shallow waters, safe from the likes of orcas and great white sharks. Southern right whales are only found in the oceans of the southern hemisphere. They inhabit waters close to Antarctica during the summer and migrate northwards to coastal areas in winter. In the sheltered bays of Peninsula Valdes, Argentina, southern right whales come to mate give birth and raise their young. Their tails alone match the wing span of a light aircraft.

11

GIANT LIVES

SOUTHERN RIGHT

12

13

GIANT LIVES

They are known to be the friendliest of the whales and are very approachable they don’t mind the divers. Tragically it’s their very friendliness that made them such easy targets for the early whalersand made them the “right” whales to hunt Today these giants are making a slow but promising recovery. Both sexes are very promiscuous and the males are equipped with a particularly astonishing adaptation for mating, a pair of giant testicles! Their two testicles together can weigh up to one tonne. The testes of the right whale are times heavier than those of the blue whale which indicates a very sexual species.

Length - 15 m Wieght - 47 Tons (Max.) Type - Baleen LIfe span - 50~60 years Food - Amphipods

SOUTHERN RIGHT

14

Southern Right Whales have the biggest penis in the animal kingdom. 12

GIANT LIVES

Underwater it becomes abundantly clear that males not only boast giant testicles but that at nine foot long they have the biggest penis in the animal kingdom. And one which appears to OH]L H TPUK VM P[Z V^U >OLU [OL` ÄUHSS` TH[L it’s belly to belly. But this is just the start for the female as she goes on to mate with the rest VM [OL THSLZ ZVTL[PTLZ \W [V Ä]L VY ZP_ H[ H time. After an hour of being spellbound by this extraordinary courtship. By mating with a variety of males the female ensures that the battle for paternity goes on inside her and not in the open seas. But it’s still the biggest male that stands the best chance of winning that battle because by having the longest penis and largest testicles OL JHU Å\ZO V\[ HU` JVTWL[P[VY»Z ZWLYT -VY male whales size really does matter.

SOUTHERN RIGHT

16

BOWHEAD WHALE Balaena mysticetus Within the Arctic Circle lives a whale three times the size of a grey whale, It’s a bowhead whale named after its enormous curved upper jaw. It’s grown to massive size for even more extraordinary reasons as it stays in the Arctic all year round it doesn’t need to be big to survive lengthy migrations and protected by the maze of shifting pack ice it has less to fear from killer whales. So why is this whale so big? 0U LHZ[LYU .YLLUSHUK H ZJPLU[PÄJ [LHTZ HYL attempting to unlock the secrets of this littleknown giant. In the last two centuries bowheads were almost wiped out by commercial whalers and are notoriously wary of humans and are remarkably alert to danger. During the winter bowheads are impossible to track but in spring they announce their presence with song. Scientists think that these are mating calls and that the bowheads may gather to breed. Bowheads are the masters of concealment able to hold their breath for up to an hour and a half The bowheads survive this cold through being a giant. The bigger and rounder the body the better it is at retaining heat. Wrapped in 50 tonnes of insulating blubber these whales are the fattest animals on the planet. Half their entire body weight is fat!

17

GIANT LIVES

BOWHEAD

12

The bowhead whale is second only in size to the mighty blue whale. Its enormous bowshaped mouth, the largest mouth of any animal, contains a baleen measuring three metres. The WSH[LZ ÄS[LY V\[ [OL [PU` JY\Z[HJLHUZ MYVT the water which make up its diet. The bowhead whale inhabits cold Arctic waters and so needs the best insulation. It’s blubber is the thickest found on any animal at half a metre. Female IV^OLHKZ HYL WLYOHWZ [OL TVZ[ ÅPY[H[PV\Z ocean mammal, constantly teasing the males into a frenzy. Bowheads use their backs to break through the ice to create vital breathing holes permanently scarring their skin in the process. These patterns HYL HZ \UPX\L HZ ÄUNLYWYPU[Z HUK OLSW PKLU[PM` each individual whale. Discoveries of ancient ivory and stone harpoon OLHKZ PU [OL ÅLZO VM PUKP]PK\HSZ Z\NNLZ[ IV^head whales may live for more than 100 years, possibly up to 200 years. This would make them the longest lived mammal known. Bowheads can live for over 200 years because they have a lower body temperature than any other whale and the lower your body temperature the slower you age. These enormous whales can afford to live life slowly roaming the rich Arctic waters simply opening [OLPY TV\[OZ HUK ÄS[LYPUN HSS [OL MVVK [OL` ULLK Uniquely a bowhead’s backbone never fuses so all that time they never stop growing.

Length - 20 m Wieght - 100 Tons (Max.) Type - Baleen LIfe span - 150~210 years Food - Copepods

12

GIANT LIVES

Bowheads are the oldest living mammals on Earth, some reaching over 200 years old.

HOW OLD IS OLD? "#"

Comparing Bowheads life span to other mammals on Earth.

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GREY WHALE

Eschrichtius robustus

Grey whales undertake the longest annual migration of any known mammal, along the coastlines between their summer feeding and winter breeding grounds. Belonging to the baleen whale group, they have plates for Ă„S[LYPUN THYPUL ^VYTZ HUK JY\Z[HJLHUZ MYVT [OL VJLHU Ă…VVY .YL` ^OHSLZ HYL ZWSP[ PU[V [^V ZLWHYH[L WVW\SH[PVUZ [OL LHZ[LYU 5VY[O 7HJPĂ„J (American) and the critically endangered western 5VY[O 7HJPĂ„J (ZPHU WVW\SH[PVU ;OL` HYL [OL only species in their genus, which in turn, is the only genus in the family. Grey whales undertake the longest annual migration of any known mammal, travelling from warm breeding grounds at the equator to their summer feeding grounds in the Arctic. Researchers have suggested that these epic journeys could also be driven by the threat of predation from killer whales. Gray whales are often covered with parasites and other organisms that make their snouts and backs look like a crusty ocean rock.

12

GIANT LIVES

GREY WHALE

12

Grey whales undertake the longest annual migration of any mammal

12

GIANT LIVES

The whale uses its snout to forage by dislodging [PU` JYLH[\YLZ MYVT [OL ZLHÅVVY 0[ [OLU ÄS[LYZ these morsels with its baleen—a comblike strainer of plates in the upper jaw. A piece of gray whale baleen, also called whalebone, is about 18 inches (46 centimeters) long and has a JVUZPZ[LUJ` T\JO SPRL H ÄUNLYUHPS >OHSLIVUL was once used to make ladies’ corsets and umbrella ribs. The gray whale is one of the animal kingdom’s great migrators. Traveling in groups called pods, some of these giants swim 12,430 miles round trip from their summer home in Alaskan waters to the warmer waters off the Mexican coast. The whales winter and breed in the shallow southern waters and balmier climate. Other gray whales live in the seas near Korea.

GREY WHALE

12

Length - 15 m Wieght - 40 Tons (Max.) Type - Baleen LIfe span - 50~70 years Food - Amphipods

Like all whales, gray whales surface to breathe, so migrating groups are often spotted from North America’s west coast. These whales were once the target of extensive hunting, and by early in the 20th century they were in serious danger of extinction. Sadly the Grey whale was hunted to extinction in the 18th century. The whales were granted protection from commercial hunting by the International Whaling Commission (IWC) in 1959 and since then the WVW\SH[PVU OHZ Z[HISPZLK PU [OL 7HJPÄJ

12

GIANT LIVES

12

DEEP THINKERS Chapter Two

HUMPBACK WHALE Megaptera novaeangliae

Humpback whales migrate seasonally from the tropics to their northern feeding grounds, and during the summer months they must feed intensely in preparation for this migration. ;OLZL THNUPÄJLU[ ^OHSLZ HYL YLUV^ULK MVY [OLPY acrobatic aerial breaching, and their beautiful yet complex songs, performed by males during courtship. Humpback whales are best known for their magical songs, which travel for great distances through the world’s oceans. These sequences of moans, howls, cries, and other noises are quite complex and often continue for hours on end. Scientists are studying these sounds to decipher their meaning. It is most likely that humpbacks sing to communicate with others and to attract potential mates. These whales are found near coastlines, feeding on tiny shrimp-like krill, plankton, and small ÄZO /\TWIHJRZ TPNYH[L HUU\HSS` MYVT Z\Tmer feeding grounds near the poles to warmer

12

DEEP THINKERS

HUMPBACK

12

07

DEEP THINKERS

winter breeding waters closer to the Equator. Mothers and their young swim close together, VM[LU [V\JOPUN VUL HUV[OLY ^P[O [OLPY ÅPWWLYZ with what appear to be gestures of affection. Females nurse their calves for almost a year, though it takes far longer than that for a humpback whale to reach full adulthood. Calves do not stop growing until they are ten years old. Humpbacks are powerful swimmers, and they \ZL [OLPY THZZP]L [HPS ÄU JHSSLK H Å\RL [V WYVWLS themselves through the water and sometimes completely out of it. These whales, like others, regularly leap from the water, landing with a tremendous splash. Scientists aren’t sure if this breaching behavior serves some purpose, such as cleaning pests from the whale’s skin, or whether whales simply do it for fun.

Length - 16 m Wieght - 40 Tons (Max.) Type - Baleen LIfe span - 45~50 years Food - Krill, plankton & ZTHSS ÄZO

HUMPBACK

12

A Humpback’s brain contains a type neuron that was believed to be unique only to humans and great apes

HUMPBACK

12

WORKING TOGETHER

Humpbacks are very intelligent and some groups use a complex method of trapping the fish which only works with clever cooporation from every whale.

HERDERS Circle the fish with flashing fins, keeping the shoal contained and preventing its escape.

CALLER The caller dives below the shoal and emits a deafening cry. As loud as a rocket launch, 180 decibels of sound pressure blasts through the water. In an attempt to escape from the noise, the panic-stricken fish are driven upwards

RING LEADER Taking up position above the herring, it begins blowing out a stream of air to create a fizzing net of bubbles. The shoal is prevented from dispersing by the herders, and driven up by the caller right into the bubble-net

Then all the whales gather underneath the fish trapped in the net. With mouths wide open, the A-team burst through the surface, engulfing their prey. By hunting together like this, each whale can catch up to half a ton of herring a day.

BOTTLENOSE DOLPHINS Eubalaena australis

11

DEEP THINKERS

Bottlenose dolphins are well known as the intelligent and charismatic stars of many aquarium shows. Their curved mouths give the appearance of a friendly, permanent smile, and they can be trained to perform complex tricks. In the wild, these sleek swimmers can reach speeds of over 18 miles (30 kilometers) an hour. They surface often to breathe, doing so two or three times a minute. Bottlenose dolphins travel in social groups and communicate with each other by a complex system of squeaks and whistles. Schools have been known to come to the aid of an injured dolphin and help it to the surface. Bottlenose dolphins track their prey through the expert use of echolocation. They can make up to 1,000 clicking noises per second. These sounds travel underwater until they encounter objects, then bounce back to their dolphin senders, revealing the location, size, and shape of their target. When dolphins are feeding, that target is often H IV[[VT K^LSSPUN Ă„ZO [OV\NO [OL` HSZV LH[ shrimp and squid. These clever animals are also ZVTL[PTLZ ZWV[[LK MVSSV^PUN Ă„ZOPUN IVH[Z PU hopes of dining on leftovers.

BOTTLENOSE

12

Length - 4 m Wieght - 500 Kg Type - Porpoises LIfe span - 45~50 years Food :THSS ÄZO

13

DEEP THINKERS

BOTTLENOSE

12

12

DEEP THINKERS

Bottlenose dolphins are found in tropical oceans and other warm waters around the globe. They were once widely hunted for meat and oil (used for lamps and cooking), but today only limited KVSWOPU ÄZOPUN VJJ\YZ /V^L]LY KVSWOPUZ HYL [OYLH[LULK I` JVTTLYJPHS ÄZOPUN MVY V[OLY species, like tuna, and can become mortally LU[HUNSLK PU UL[Z HUK V[OLY ÄZOPUN LX\PWTLU[ All dolphins, including the bottlenose, are porpoises. Although some people use these names interchangeably, porpoises are actually a larger group that also includes animals like the orca and the beluga whale. Bottlenose dolphins have been observed to breach up to 16 feet (4.9 meters) out of the water, landing with a splash on their back or side.

BOTTLENOSE

12

DEEP THINKERS

Scientists think that we will be able to talk to Dolphins in 5 years

VOICES OF THE SEA

Chapter Three

SPERM WHALE Physeter macrocephalus

Sperm whales are easily recognized by their massive heads and prominent rounded foreheads. The mighty sperm whale is a multiple record-breaker. It is the largest of the toothed whales with some males reaching 20 metres in length. Its enormous box-like head with left-sided blow hole contains the biggest brain of any living animal known to have lived on Earth. It is also the deepest diving mammal, reaching depths of 3,000 metres (nearly two miles) although the average dive is between 300 and 600 metres. These dives can last for a couple of hours due to the oxygen stored in their muscles before the whale has to come up for breath. Their heads also hold large quantities of a substance called spermaceti. Whalers VUJL ILSPL]LK [OH[ [OL VPS` Ă…\PK ^HZ ZWLYT I\[ scientists still do not understand the function of spermaceti. One common theory is that the Ă…\PK¡^OPJO OHYKLUZ [V ^H_ ^OLU JVSK¡OLSWZ the whale alter its buoyancy so it can dive deep and rise again. Until recently, no-one knew how sperm whales hunt in the abyss, scientists now have a theory. The reason sperm whales dive so deep is that there’s lots of food down there including giant squid which is over 30 feet long. A mile down, there’s no light. The whale must Ă„UK P[Z WYL` [OYV\NO LJOVSVJH[PVU PU[LYWYL[PUN the echoes of the clicks it makes. But these are no ordinary clicks. These hunting clicks are the loudest sounds made by any living thing, SV\KLY [OHU H [O\UKLYJSHW 7YVK\JLK PU P[Z Ă„]L ton nose, the whale’s clicks travel backwards, [OLU HYL YLĂ…LJ[LK MVY^HYKZ [OYV\NO H ZLYPLZ VM VPS Ă„SSLK SLUZLZ ^OPJO MVJ\Z [OLT PU[V H UHYYV^ sound beam, like a sonic laser. These toothed ^OHSLZ LH[ [OV\ZHUKZ VM WV\UKZ VM Ă„ZO HUK ZX\PK¡HIV\[ VUL [VU RN WLY KH`

05

VOICES OF THE SEA

SPERM

12

Sperm whales hunting clicks are the loudest sounds made by any living animal on Earth

Sperm whales are often spotted in groups (called pods) of some 15 to 20 animals. Pods include females and their young, while males may roam solo or move from group to group. Females and calves remain in tropical or subtropical waters all year long, and apparently practice communal childcare. Males migrate to higher latitudes, alone or in groups, and head back towards the equator to breed. Driven by [OLPY [HSL Ă…\RL HWWYV_PTH[LS` MLL[ TL[LYZ from tip to tip, they can cruise the oceans at HYV\UK TPSLZ RPSVTL[LYZ WLY OV\Y

Length - 20 m Wieght - 60 Tons (Max.) Type - Toothed LIfe span e `LHYZ Food - Squid

SPERM

12

Sperm whales sleep in short bursts usually in a vertical position

12

VOICES OF THE SEA

These popular leviathans are vocal and emit a series of “clangs” that may be used for communication or for echolocation. Animals that use echolocation emit sounds that travel underwater until they encounter objects, then IV\UJL IHJR [V [OLPY ZLUKLYZ·YL]LHSPUN [OL location, size, and shape of their target. Sperm whales were mainstays of whaling’s 18th HUK [O JLU[\Y` OL`KH` ( T`[OPJHS HSIPUV sperm whale was immortalized in Herman Melville’s Moby Dick, though Ahab’s nemesis was apparently based on a real animal whalers called Mocha Dick. The animals were targeted for oil and ambergris, a substance that forms around squid beaks in a whale’s stomach. Ambergris was (and remains) a very valuable substance once used in perfumes. Despite large population drops due to whaling, sperm whales are still fairly numerous.

SPERM

12

:LH 3L]LS

124M Free diving record with fins

DEEP SEA HUNTING Sperm whales dive deep and use their hunting clicks to locate their prey.

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1000M Deepest light can penetrate

The hunting clicks are produced at the front of the whales 5 tonne nose. They then travel backwards through the spermaceti and are reflected forwards through a series of oil filled lenses called junk chambers which focuses them into a narrow sound beam, like a sonic laser. T

3000M Maximum depth Sperm whales dive to hunt

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Inside Sperm Whale Head

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Sperm whales make the loudest sound of any living animal. Their hunting clicks reach 230 dB (Decibels). In the air it would still reach a staggering 170 dB

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130dB 140dB Pain thresh hold for humans (125dB)

Sperm whale

170dB

BOTO RIVER DOLPHIN Inia geoffrensis

Botos live exclusively in the the South America in the Amazon and Orinoco river basins. They have a ridge along their back rather [OHU H KVYZHS ÄU HUK P[Z MH[ OLH]` IVK` PZ Z\YWYPZPUNS` ÅL_PISL 7HKKSL SPRL ÅPWWLYZ ^OPJO move in a circular motion provide exceptional manoeuvrability, making up for a lack of speed. Even swimming backwards on some occassions! The Amazon & Orinoco river basins provide all the food in its highly diverse diet, PUJS\KPUN H[ SLHZ[ KPMMLYLU[ ZWLJPLZ VM ÄZO The Botos use two completely separate sound systems. Communication clicks and busses and their echolocation clicks and busses. The Boto’s clicks and buzzes are focused into a sound beam by its bulging forehead melon. The beam works like a sonic head-torch allowing the dolphin to build up a clear picture of its surroundings in the murky water.

11

VOICES OF THE SEA

Length - 2.5 m Wieght - 185 Kg Type - Porpoises LIfe span - 15~20 years Food :THSS ÄZO JYHIZ

BOTO

12

The Botos need all their manoeuvrability and all the sonar skills they possess to operate in the sort of underwater environment that the Amazon provides. It’s as tangled and spiny underwater as it is on the surface and the water is very cloudy and dark like a well brewed tea. While all dolphins can echolocate, Botos’ clicks have a higher frequency and better resolution than any other dolphin, allowing them to distinguish objects as small as a pin. Even in zero visibility, JH[JOPUN ÄZO PZ JOPSK»Z WSH`

13

VOICES OF THE SEA

BOTO

12

12

VOICES OF THE SEA

Boto’s echolocation is so accurate they can distinguish objects as tiny as a pin

NARWHAL

Monodon monoceros

The narwhal is the unicorn of the sea, a pale-colored porpoise found in Arctic coastal waters and rivers. These legendary animals have two teeth. In males, the more prominent tooth grows into a swordlike, spiral tusk \W [V MLL[ TL[LYZ SVUN ;OL P]VY` [\ZR [VV[O grows right through the narwhal’s upper lip. Scientists are not certain of the tusk’s purpose, but some believe it is prominent in mating rituals, perhaps used to impress females or to battle rival suitors. Females sometimes grow a small tusk of their own, but it does not become as prominent as the male’s. Narwhals are related to bottlenose dolphins, belugas, harbor porpoises, and orcas. Like some other porpoises, [OL` [YH]LS PU NYV\WZ HUK MLLK VU Ă„ZO ZOYPTW ZX\PK and other aquatic fare. They are often sighted swimming PU NYV\WZ VM [V I\[ NH[OLYPUNZ VM O\UKYLKZ¡VY L]LU ZL]LYHS [OV\ZHUK¡UHY^OHSZ OH]L ILLU YLWVY[LK Sometimes these groups become trapped by shifting pack ice and fall victim to Inuit hunters, polar bears, or walruses.

17

VOICES OF THE SEA

NARWHAL

12

12

VOICES OF THE SEA

The charismatic narwhal is the legendary ‘unicorn of the sea’. It’s also thought that narwhal horns used in trade or washed up on beaches gave credence to the myth of unicorns on land. The horn is more properly called a tusk. Narwhals only have two teeth and in the males, the left one grows out of the jaw into a long spiralled tusk that can reach 2.5m in length and is prone to breaking. Suggested uses for such an impressive appendage include to spear food, for defence and as a weapon for competing males. However, its most likely use is to PTWYLZZ MLTHSLZ HZ HU PUKPJH[PVU VM [OL Ă„[[LZ[ TH[L Narwhals are inhabitants of Arctic waters and are found at all depths. They tend to stay close to loose pack ice, where breathing holes are maintained through the sheets of ice. The narwhal is the unicorn of the sea, a pale-colored porpoise found in Arctic coastal waters and rivers. These legendary animals have two teeth. In males, the more prominent tooth grows into a swordlike, ZWPYHS [\ZR \W [V MLL[ TL[LYZ SVUN ;OL P]VY` tusk tooth grows right through the narwhal’s upper lip. Scientists are not certain of the tusk’s purpose, but some believe it is prominent in mating rituals, perhaps used to impress females or to battle rival suitors. Females sometimes grow a small tusk of their own, but it does not become as prominent as the male’s.

Length - 4 m Wieght - 500 Kg Type - vvLIfe span 45~50 years Food :THSS Ă„ZO

NARWHAL

12

KILLER WHALE Orcinus orca

12

VOICES OF THE SEA

Killer whales are actually the largest species RI GROSKLQ 7KHLU GRUVDO ÀQ FDQ EH XVHG WR recognise individuals, and in males can measure DQ LQFUHGLEOH PHWUHV LQ KHLJKW .LOOHU ZKDOHV are found in every ocean on the planet, and DV ZHOO DV EHLQJ WKH PRVW ZLGHO\ GLVWULEXWHG they also hold the title for fastest sea mammal, reaching speeds of up to 55kph. A distinguished marine predator, these strikingly marked killers KDYH HYHQ EHHQ NQRZQ WR KXQW GRZQ JUH\ DQG EOXH ZKDOHV .LOOHU ZKDOHV DUH IRXQG LQ all oceans, from the frigid Arctic and Antarctic regions to tropical seas.

Length T Wieght [VUULZ Type - Porpoises LIfe span - 50-80 years Food - Fish, seals, walruses and other whales

KILLER

12

Killer whales as a species have a diverse diet, although individual populations often specialize in particular types of prey. Some feed exclusively RQ ÀVK ZKLOH RWKHUV KXQW PDULQH PDPPDOV such as sea lions, seals, walruses and even large whales. Killer whales are regarded as apex predators, lacking natural predators. Killer whales are highly social; some populations are composed of matrilineal family groups which DUH WKH PRVW VWDEOH RI DQ\ DQLPDO VSHFLHV 7KHLU sophisticated hunting techniques and vocal EHKDYLRUV ZKLFK DUH RIWHQ VSHFLÀF WR D SDUWLFXODU group and passed across generations, have EHHQ GHVFULEHG DV PDQLIHVWDWLRQV RI FXOWXUH

KILLER

12

Killer Whales use herding calls to bunch fish together making them easier to catch

KILLER

12

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