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00:00I
00:30With the help of a little modern technology,
00:57I've been listening to the calls of one of the great predators of the ocean,
01:02feeding maybe two or three miles from here.
01:06Surprising though it may seem, those are the sounds of the humpback whale.
01:15Close to, the noise is staggering.
01:21Hunting herring is far from easy, but the small fish have a major weakness.
01:27They use tiny sounds to control the movements of their shoals,
01:32so their sense of hearing is acute.
01:34And at 180 decibels, the humpback screams are completely overpowering.
01:39This is predation.
01:44It's the end of the power.
01:46This is predation on a massive scale.
01:53Very few of the herring are lucky enough to fall back into the sea unharmed.
02:00This is predation on a massive scale.
02:06Very few of the herring are lucky enough to fall back into the sea unharmed.
02:12That humpback scream as they hunt has only been discovered recently.
02:17Indeed, research is now revealing that the whales,
02:19far from being the gentle giants of popular belief,
02:21have a very aggressive side to their characters.
02:26Southeast Alaska in mid-December.
02:33Several hundred humpbacks have spent the entire summer here,
02:38cruising between the islands of the Inside Passage,
02:40feeding on the rich plankton and fish stocks.
02:42This is now revealing that the whales,
02:43far from being the gentle giants of popular belief,
02:45have a very aggressive side to their characters.
02:48Now the chill of approaching winter heralds a change.
03:18Thousands of old squaw duck have migrated here from the polar north.
03:35Compared to the Arctic these conditions are comparatively mild
03:38and the ducks will spend the winter feeding in these sheltered waterways.
03:43But for most of the humpbacks,
03:49there is a pressing need to set off on an epic journey of their own,
03:53even though they are at no risk from the coddle.
03:58By the end of December, the whales are heading south.
04:16Blowing for breath regularly and travelling singly or in small groups,
04:22the humpbacks keep up a steady pace of about six miles an hour.
04:29The sound of their passage attracts a pod of Pacific white-sided dolphins.
04:36Eventually the whales must set out into the open ocean for a voyage of three and a half thousand miles.
04:55The islands of Hawaii in January.
05:02The volcanic sea cliffs here are the tallest in the world.
05:16And in the vast Pacific Ocean they provide rare protection from the wind and swell.
05:25So this sub-tropical water is an ideal sheltered nursery in which humpbacks can raise their young.
05:32This was the reason for the Great Migration to breed.
05:42Hawaii is visited by about five thousand humpbacks every winter.
05:46Several hundred of them are mothers with their calves.
05:55The maternal bond is exceptionally close.
05:58This fifty-ton cow and her four-week-old calf will be inseparable for about ten months.
06:07As he's still quite a weak swimmer, she gives him an energy-saving piggyback ride
06:12and gently nudges him up to the surface to help him breathe.
06:17But they are not alone.
06:22Another large adult cruises in to join them.
06:26At first, some scientists thought visitors like this were females, aunts, helping out with the calves.
06:33In fact, they are males.
06:35And probably the last thing on this escort's mind was the calf's well-being.
06:52To be continued...
06:53The
07:19This trio of cow, calf and male escort
07:28is a common social group in the breeding area
07:31but the liaison is tense
07:33because soon after giving birth
07:35the cow is ready to mate again
07:37The escort is almost certainly waiting for his chance
07:49but the cow has other more pressing engagements
07:52Her calf needs to suckle regularly
07:54and nudges in under her huge four metre pectoral fins
08:01For now, the male seems patient enough to wait
08:19The lungs of baby whales are only small
08:26so his mother has to release him regularly
08:29from the protective clasp of her fin
08:31The adults can remain underwater for up to 40 minutes
08:38For the calf, it's a different story
08:45Every four or five minutes, he has to surface all by himself
08:49and gulp for air
08:5120 metres below, the adults wait for the calf's return to the nipple
09:17Schooling mackerel also head for the immense bodies
09:31perhaps using them as a temporary shelter
09:33in the vast expanse of the open ocean
09:36The small group may remain together for days at a time
09:43gently moving about between the islands
09:45Idyllic as their setting may seem
09:51it's vital that the calf develops in size and strength quickly
09:55His survival may depend upon it
09:58One month has passed
10:08The calf is doing well, hugged protectively by his ever vigilant mother
10:14As before, as soon as he needs to breathe, she releases him
10:21But trips to the surface are no longer so daunting or frequent
10:26The calf has grown both in size and independence
10:40A breathing expedition now is a perfect excuse for some fun
10:47A breathing expedition now is a perfect excuse for some fun
11:02The play is excellent for improving much needed stamina
11:09But the commotion may also attract the attention of other whales and people
11:16Like scientist Jim Darling
11:17He's been working with humpbacks for 18 years
11:18slowly trying to discover more about their behaviour
11:23Because if we are to conserve these great whales properly
11:25We must know what their needs really are
11:30Humpbacks are world-famous
11:33Humpbacks are world-famous
11:35For the beauty of their singing
11:36But Jim's main interest is in its social function
11:38He's been working with humpbacks for 18 years
11:42Slowly trying to discover more about their behaviour
11:45Because if we are to conserve these great whales properly
11:48We must know what their needs really are
11:58Humpbacks are world-famous
12:00For the beauty of their singing
12:02But Jim's main interest is in its social function
12:05So he uses a hydrophone to locate and listen to singers
12:09Only males sing
12:30So it's almost certainly a sexual display of some kind
12:37And the Hawaiian singers often lie motionless
12:41With their pectoral fins thrust down
12:43And held stiffly outwards
12:45All the whales sing roughly the same song
12:50A rigidly structured pattern of themes
12:52Lasting about 12 minutes
12:54Which can be repeated almost without break
12:57For hours on end
12:58A passing whale eventually moves in
13:00To check out the whales
13:01For hours on end
13:02A passing whale eventually moves in
13:03To check out the singer
13:04Is this a female?
13:05Attracted by the whales?
13:06By the bull's voice
13:07Or another male?
13:08Assessing the strength of the whale?
13:09In any event
13:10The singer is a female
13:11At the whale is a female
13:12A passing whale eventually moves in
13:14To check out the singer
13:16Is this a female?
13:17Attracted by the bull's voice
13:18Or another male?
13:19Assessing the strength of the competition
13:20In any event
13:21The singer is disturbed
13:22And quickly moves on
13:23Sometimes the intruding whale
13:28Will catch up with the singer
13:30And swim with it for a few minutes
13:32But they'll be a bit
13:37A passing whale eventually moves in
13:39To check out the singer
13:40Is this a female?
13:43Attracted by the bull's voice?
13:44Or another male?
13:45Assessing the strength of the competition
13:46In any event
13:47The singer is disturbed
13:48And quickly moves on
13:49with it for a few minutes, but is this passion, or war?
13:58Jim's task is to identify and sex the incoming whales to try and solve the
14:03riddle.
14:08First he takes photos of the tail flukes,
14:13and then waits to snap the dorsal fin as well. Both are uniquely marked or shaped,
14:22and will identify the animal for future reference.
14:27Ah, I think it is the one with the white tail.
14:31But sexing a whale is another matter altogether.
14:35It'll just stay along right at this distance.
14:37The best technique is to take a skin sample.
14:40OK, that's good.
14:43But it's a very difficult thing to do.
14:45Just manoeuvring a boat close to a whale without disturbing it takes great skill.
14:50So research assistant Karen reacts instantly to every direction.
14:54A little bit more this way.
14:57And they need to get close enough to fire a low-powered dart
15:01that collects a tiny plug of skin.
15:05Done correctly, it causes no alarm.
15:07The sample will be sent back to the laboratory for DNA analysis.
15:14All right.
15:16Good.
15:18It will reveal the whale's sex and genetic details.
15:22And Jim's preliminary results have shown that all the joining whales he's tested are male.
15:27So it seems that the song could indeed be an elaborate communication of male status.
15:34Perhaps it's war after all.
15:40And when it comes to competing for a mate, the bulls do more than just sing.
15:45There are over 1,000 of them around Hawaii, so the competition for females is intense.
15:54Even cows with calves are fair game.
15:57And the females may actually encourage the bull's attention.
16:01For the calf, this will be a testing time.
16:03This bull with distinctive white pectoral fins is the escort, and he moves in quickly to claim his right.
16:17But the cow still heads off with her calf close beside her.
16:29And the male soon picks up the chase.
16:32The escorted group changes course.
16:51Perhaps the bull is trying to shake off the persilas.
16:56But following them is easy.
17:02The escort tries a threat display by blowing jets of bubbles underwater.
17:08Perhaps it helps establish a dominance pecking order in the queue following the cow.
17:28Another bull moves closer.
17:46Blowing like a surfacing submarine, the escort moves in to intercept.
18:05The female lifts her head clear of the water.
18:08After swimming at 10 miles an hour for some minutes, the calf is tiring and flails in distress.
18:25The bulls are overhauling them.
18:27As yet another male powers up from behind, the cow finally stops.
18:51Slapping her flipper loudly.
18:53With balls circling her continuously, she starts tail slashing.
19:07Perhaps to fend off the less desirable mates.
19:14And in another attempted display of dominance, the escort moves towards her with his fins held stiffly outstretched.
19:21Undeterred, up to seven males circle the cow, totally surrounding her.
19:31They hoot as they manoeuvre for prime position.
19:35The competition becomes yet more intense as one of the bulls chases the escort away.
19:46Now the cow is an unprotected target.
20:02During the ensuing confusion, it's possible that she will be finally mated.
20:07Thrashing weakly, the calf by now is close to exhaustion.
20:08Thrashing weakly, the calf by now is close to exhaustion.
20:09So his mother glides up to reassure him.
20:10Thrashing weakly, the calf by now is close to exhaustion.
20:11So his mother glides up to reassure him.
20:12And, if necessary, give physical support.
20:13And, if necessary, give physical support.
20:14And, if necessary, the calf by now is close to exhaustion.
20:15Thrashing weakly, the calf by now is close to exhaustion.
20:32Thrashing weakly, the calf by now is close to exhaustion.
20:34Thrashing weakly, the calf by now is close to exhaustion.
20:35Thrashing weakly, the calf by now is close to exhaustion.
20:36So his mother glides up to reassure him.
20:37And, if necessary, give physical support.
20:41support. But for the moment they are ignored. The bulls are too engrossed in
20:50a conflict where collisions may even draw blood.
20:59By now the cow has probably mated successfully so she takes the chance to
21:04slip away and not before time. Her calf desperately needs to suckle.
21:10If these chases happen too often it's possible that the stress and lack of
21:15feeding could be fatal to calves.
21:27By February Jim's team is joined by the renowned underwater stills photographer
21:32Flip Nicklin. The two have worked together on and off for over 18 years and
21:37they're quickly amongst the whales.
21:50Suddenly they notice something strange about one of them. It dives with a
21:55lopsided tail.
22:01It's a style that's reminiscent of a whale that was a major landmark in their research
22:05and they last saw him 18 years ago.
22:08They approach with a real sense of growing excitement. Could it be the same whale?
22:18This is a unique opportunity.
22:3418 years ago Flip and his father Chuck became the first people to dive down to a
22:40singing whale.
22:55Their breakthrough was to hold their breath instead of using scuba gear with its noisy bubbles and the photos
23:01they took were the first proof that singers are male.
23:09Diving this close to a singing whale is an extraordinary experience. Its voice is so strong that the
23:16whole of Flip's body is physically vibrated.
23:25He's searching for identifying marks in the whale's tail because Frank had a big
23:30ragged tear in his left fluke with deep lacerations from a cable entanglement.
23:35Amazingly, after all this time, Flip was indeed looking at the very same tail.
23:49It was Frank.
23:56Unable to hold his breath any longer, Flip is forced to head for the surface.
24:01Remarkable, though, Frank's rediscovery was, it also revealed just how little we know about these animals.
24:11Where had he been during all this time?
24:16It's possible that he had visited Hawaii every year and had simply not been seen.
24:21But there are other Hawaiian humpbacks that have been spotted in breeding grounds off Japan and
24:31islands near to Mexico's Pacific coast.
24:36It appears that they are all part of the same population, sharing similar songs and wandering
24:42as they please.
24:44But there are humpback song cultures in the Pacific that Frank is unlikely ever to meet.
24:59February, on the edge of the Antarctic ice shelf.
25:03The northern hemisphere is still in midwinter, but down here it's high summer, and humpbacks visit
25:09annually to harvest the rich pickings.
25:12This is an entirely different group of whales to those in Hawaii.
25:19All too soon, severe cold will drive them north to breeding grounds of their own.
25:24But they remain south of the equator, amongst the South Pacific islands of Fiji and Tonga.
25:29There are only about 100 humpbacks around Tonga, because, until recently, they were hunted.
25:41And it's the first time that Flip Nicklin's father, Chuck, has visited these islands.
25:46So he's far from certain of finding whales.
25:53But, after a week of waiting, he's finally spotted some activity and sets off to investigate.
25:59He approaches as quietly as he can.
26:19His luck holds.
26:21This is the first time he's ever seen a Tongan whale.
26:24And it's a mother and calf.
26:26Edging closer reveals that the calf is very young.
26:31The crease on its side is from being curled up inside its mother's womb.
26:35And, remarkably, it's almost pure white.
26:38In fact, southern whales are quite different in appearance from those of the north, and even the adults have far more white markings.
26:50Although, Chuck has been diving with whales for 30 years, swimming this close is still a huge thrill.
27:01And the cow and her calf seem totally unconcerned.
27:04Perhaps there are so few bulls here that there isn't as much sexual harassment as in Hawaii.
27:10So the cow is more tolerant.
27:11But there are some males here.
27:19The song is very different to those of the northern Pacific, with extraordinary chirps and screams.
27:39This singer's action is also quite different.
27:43Even whilst it rolls and plays, the song keeps booming out.
27:48It seems a much more light-hearted performance.
27:51And it's easier to make an approach.
27:52Although they can cross the tropics,
28:21Southern whales are governed by the seasons of the south.
28:25So they breed six months later than the northern Pacific humpbacks,
28:28and they must also head south to feed.
28:34This male's song will probably never be heard north of the equator,
28:39and will always sound quite different.
28:41He's from a distinct population, with its very own language.
28:45Researching the movements and cultures of Wales on a global scale is incredibly difficult.
28:54How on earth can you follow a migrant across thousands of miles?
28:57One man who does just that is Professor Bruce Mate.
29:13He's using high-tech telecommunications to track some of the Hawaiian whales on their northbound migration.
29:20A satellite transmits positioning signals from tagged animals,
29:29revealing their precise location day or night.
29:32The results are already extraordinary.
29:35Hawaiian humpbacks don't have one single destination.
29:39They radiate out to feeding areas all over the North Pacific.
29:42This group is nearing the coast of southeast Alaska.
29:55The rugged coastline is fringed by hundreds of mountainous islands,
30:00and the cold water that separates them is some of the most productive in the world.
30:05At the end of their long journey, the whales seem almost exuberant.
30:09They breach and slap their flippers repeatedly.
30:27It's a phenomenal display.
30:30It takes enormous strength to hurl a 50-ton body out of the water.
30:39The strong tidal rips that run here literally seize with fish.
31:01Countless millions of herring cruise near the surface,
31:11slipping individual plankton from the dense summer bloom.
31:16But catching plankton can be a risky business.
31:20Herring is a favourite on Alaska's coastal menu.
31:24The shoal bunches into a protective ball,
31:31but it's little defence against diving guillemots and orklets.
31:43From above, young herring gulls add to the feeding frenzy,
31:47and the commotion attracts a dogfish.
31:49Before long, there are extraordinary numbers of these small sharks
32:06on the prowl for herring.
32:11But to try and escape, the shoal has dived deep.
32:14Depth is no guarantee of safety.
32:25A wall of bubbles rises up to the surface, expanding noisily.
32:29The line keeps growing, until it becomes a complete ring.
32:43Corralled by the vertical net of bubbles,
32:45the herring are trapped at the surface.
32:50It's the worst place to be.
32:53A lone humpback lunges into the centre of his bubble net.
33:05The whale can repeat this attack every few minutes,
33:08for hours on end.
33:09The spread of its jaws is over four metres,
33:23and pleats in the whale's throat
33:25stretch enormously along half its body length,
33:28allowing it to engulf hundreds of gallons of water.
33:34A single gulp can devour an entire shoal.
33:37A single gulp can be.
33:39A single gulp can be.
33:39A single gulp can be.
33:41A single gulp can be.
33:59Rich feeding like this attracts dozens of whales,
34:03often in large groups,
34:04and little is known about the social structure of the groups or their movements.
34:11Bruce Mate is keen to use his satellite techniques
34:14to discover more about whale behaviour in feeding areas.
34:28He believes that knowing where the most important humpback feeding areas are
34:33and how the whales utilise them
34:35will help us to ensure that the right protection is given
34:38both to their environment and the whales themselves.
34:49But first, he must tag some whales.
34:55His team uses a manoeuvrable boat for close approaches.
35:00They must be close enough to dart the whales with a small satellite transmitter.
35:09Barb, the skipper, has to time her runs perfectly
35:13to get Bruce into exactly the right position at the right time.
35:18If, at the last split second, the whale surfaces in slightly the wrong place,
35:23they abort the pass.
35:24It's an enormously skilled and tense operation.
35:33Safety off.
35:39But let it come up again.
35:41Let it come up again.
35:42If it will.
35:44Okay, go, go, go, go, go, go, go, go, go.
35:46Yes.
35:48Yes.
35:50Woo-hoo!
35:51Yes, indeed.
35:53All right.
35:54Watch your hands now.
35:57All right.
35:59Woo!
36:00Very good.
36:02After retrieving the dart sleeve with a thin line,
36:05Bruce and his crew will take photos of the tagged whales for reference.
36:08Woo!
36:09Woo!
36:09Woo!
36:10Woo!
36:11Woo!
36:11Woo!
36:12Woo!
36:12Woo!
36:13Woo!
36:13Woo!
36:13Woo!
36:14Woo!
36:14Woo!
36:14Woo!
36:15Woo!
36:15Woo!
36:16Woo!
36:16They're still far from certain that a tag will work.
36:25A satellite has to be able to pick up its signals.
36:39Even with a satellite in the right position,
36:41the system will only operate if a tagged whale comes to the surface, the blow.
36:46And even then, if the transmitter is angled incorrectly, they won't receive a signal.
36:55To find out if everything is working, Bruce needs to get to a phone.
36:59It's kind of exciting.
37:00It's kind of exciting.
37:01It's kind of exciting.
37:02It's kind of exciting.
37:03A week now.
37:04First time.
37:05We're connected.
37:06We've got data.
37:07Come on over and take a look.
37:14Great.
37:15All right.
37:15All right.
37:16All right.
37:17This is neat.
37:18Look at this.
37:19All right.
37:20Look at this.
37:21All this stuff.
37:22Oh, that's amazing.
37:23843.
37:24This is just the last.
37:25That's the first one we tagged.
37:26Yeah.
37:27On the second.
37:28Right.
37:29Wow.
37:30Are we hearing from all five whales?
37:31Can't tell yet.
37:32It's still giving us all the first whale's data.
37:33Still scrolling by.
37:34We've got so much.
37:35Look at all that messages.
37:36Eight messages in one orbit.
37:37Right.
37:38Yeah.
37:39And it's just the start.
37:40You know, with everything going well, we're going to have data come in for a long time.
37:42Oh, that is so great.
37:43Their excitement is justified.
38:02Data from the summer tagging has shown that the whale groups are flexible.
38:06The numbers and individuals change constantly.
38:10They've even found that the animals move around, seeking out the best food hotspots.
38:17But if the fishing is good, they'll stay in one area for weeks at a time.
38:25And dense fish stocks attract more than just whales.
38:40Per se in boats use a mechanical version of the humpback's bubble netting technique.
38:59Often whales and fishermen will work in the same area.
39:04even for the same catch but by June the fishing boats are not allowed to land
39:10herring they're working the summer salmon run instead
39:19but salmon eat herring and plankton so the whales may still find a catch
39:24alongside the boats
39:28once the fishermen have located a shoal on the echo sounder they run the net out with a
39:36powerful launch eventually making a complete circle and enclosing their targeted shoal
39:48the base of the net is closed and the fish pulled up to the boat
39:58by contrast whales use the surface as the final trap for their catch
40:21when the whales are close by great care is needed to ensure that one doesn't get caught up in the net
40:27as soon as an area is cleaned out or the prey move on the humpbacks like fishermen move on as well
40:57cruising the island channels in search of fresh herring shoals
41:01when a new shoal is located it may be deep or dispersed
41:06scientists have known about bubble netting for years but they've only recently discovered the
41:13whales ultimate weapon for destroying the fish shoals coordination and for herding the catch
41:18the screech the scream
41:24Oh, my God.
41:54Oh, my God.
42:24The results are devastating.
42:41Oh, my God.
43:11Surprisingly, only one or two whales in a group set the nets or scream.
43:20So whether this is a choreographed team effort or the stealthy poaching from a particularly efficient bubble netter,
43:33no one is entirely sure, but the effect is still lethal.
43:38And they'll feed like this for five or six months solid.
43:43This is predation on a scale matched perhaps only by man.
43:48Oh, my God.
44:02BIRDS CHIRP
44:05BIRDS CHIRP
44:09BIRDS CHIRP
44:14BIRDS CHIRP
44:17BIRDS CHIRP
44:18BIRDS CHIRP
44:20BIRDS CHIRP
44:23BIRDS CHIRP
44:25BIRDS CHIRP
44:27BIRDS CHIRP
44:28Witnessing this, it is impossible to live with the image
44:31of a humpback as just a gentle giant.
44:39Capable of great tenderness, but also fierce infighting,
44:43they make journeys all over the oceans,
44:45but still have distinct population and language cultures.
44:49Above all, they are phenomenal hunters.
44:53The humpback whale truly is a giant of the oceans.
45:01The humpback whale.
45:20Continued celebrations to mark 40 years
45:22of the BBC's Natural History Unit.
45:24David Attenborough returns this Saturday night at 6 o'clock
45:27for a wildlife night on BBC Two.
45:30Here on BBC One next, Enya hits the high notes on the National Lottery draw.
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