00:03over half of all animals in the open
00:16currents jellyfish cross entire oceans
00:20feeding on whatever happens to tangle
00:28tentacles some can grow to a meter even
00:33across and when by Lucky chance they
00:37encounter a patch of sea rich in
00:39Plankton their numbers
01:25it's such a successful strategy the
01:28jellies are one of the most common life
01:41planet but among the jellies and looking
01:44somewhat like them is a rather more
01:47complex and Sinister
01:54creature the Portuguese man of
02:03it floats with the help of a gas filled
02:05bladder topped by a vertical
02:09membrane with that serving as a sail it
02:13maintains a steady course through the
02:40long threads trail behind it some as
02:48long each is armed with many thousands
02:54cells a single tentacle could kill a
02:57fish or in rare cases a human
03:05but among its lethal tentacles lks a
03:08Mana War fish that feeds by nibbling
03:18them once this fish has some resistance
03:21to the stings it must still be extremely
03:27careful most other fish
03:51lucky a tentacle has caught this one and
04:13paralyzed specialized muscular tentacles
04:16transfer the victim to others that
04:18digest the catch liquefying it with
04:30eventually all that is
04:44husk this voracious man of war May
04:47collect over a hundred small fish in a
05:19the struggle to survive in our green
05:21Seas can have far reaching
05:26consequences once a year one particular
05:30Meadow in Australia is
05:39transformed around the first full moon
05:58crabs for the past year they've been
06:13waters now they march across the
06:36hundreds of thousands of
06:46them they clamber over one
06:54another creating great
07:08long they're not seeking mates neither
07:13eggs they have come here in order to
07:20grow like all crabs their bodies are
07:23enclosed in a hard unexpandable
07:29so to grow they have to break out of
07:42it and that allows the soft one that has
07:46developed beneath to
07:55expand it will take days for the new
08:12its legs are so limp that they won't
08:18properly the crab is
08:21unprotected and in great
08:37Stingray it's huge about 4 M
08:42long it wants a soft freshly moled crab
08:46that will be easier to
09:10the crabs try to stick
09:19together but now disturbed by the ray
09:32crab is too weak to keep up with the
09:49crowd the safest place is right in the
09:54pile that is why they have all assembled
10:24numbers but the vast majority of the
10:29and within the next few days they will
10:32be ready to return to the depths and
10:34resume their lonely wanderings in search
10:54graveyard but the Triumph of 100,000
11:06molted a Sally Lightfoot
11:11crab one of thousands of shore crabs
11:14just waiting for their
11:18moment every day they gather on the
11:25Brazil waiting for the tide to go out
11:37which exposes their feeding
11:40grounds seaweed covered rocks 100 m from
11:54shore getting there is a race against
12:05they leap from rock to
12:20rock these crabs seem to be afraid of
12:54eel the chain Moray is a specialist crab
13:04Hunter its blunt teeth can easily grip
13:14shell it's the crabb's deadliest
13:27enemy but the crabs feeding grounds are
14:08halfway but the enemy has other
14:25land to reset the ambush
14:32to feed the crabs must keep
14:40going but nowhere is
14:46safe an octopus also a crab
15:16the crabs make a dash for
15:54it risking life and limb to graze on the
16:02pastures but in 2 hours time when the
16:08turn they will have to run the gauntlet
16:23again in a far corner of Southeast Asia
16:32triangle a Custer of the richest coral
16:42world undersea cities crammed full of
16:52life as in any crowded Metropolis there
16:56is fierce rivalry for space
17:12partner but the reef is also a Place
17:47cuttlefish it specializes in hunting
18:00but a large crab is a dangerous
18:11Quarry it has powerful
18:16claws the Cuttlefish however has a
18:26Talent its skin contains millions of
18:29pigment cells with which it can create
18:32everchanging colors and
18:43patterns and that apparently hypnotizes
19:10a cuttlefish may be clever but a shark
19:42hunt a new Target but the same
20:03for those that manage to establish
20:06themselves in these bustling undersea
20:09cities there can be great
20:14rewards during the dry season over half
20:17a million turns Crow onto this remote
20:30their chicks are still in their dark
20:38plumage they vary in
20:48age whilst the more advanced chicks take
21:00others aren't quite ready
21:21yet those just starting to learn to fly
21:25use the shallow Lagoon that occupies the
21:28center of the atol as their training
21:32ground it's difficult for some of them
22:14treales usually they are solitary
22:18Hunters but about 50 of them have come
22:21here from neighboring reefs attracted by
22:23this abundance of potential
22:34the fledglings stay out of the water if
22:38can they even drink on the
22:59if the chalia to catch one now they have
23:13game so there is a fish here that
23:16amazingly has a brain capable of
23:20calculating the air speed altitude and
23:56the time comes when when every fledgling
23:58has to take to the air and collect food
24:25itself their parents he to the training
26:06survive they must learn
26:16quickly after a month of practicing over
26:19the Lagoon the youngsters start to leave
26:22and take their chances out over the Open
26:34out here on the sand Flats there is safe
26:47some a family of Saddle black clown fish
26:51have found an excellent
26:55home the tentacles of the this carpet
27:01kill but the clown fish are immune to
27:10poison so they can shelter from
27:17danger in return the fish keep the
27:28as with all clownfish the family is
27:33female her white face marks her out as
27:42boss the dommin of male has to prove his
27:48tirelessly removing debris and generally
27:51keeping on top of the
28:14his greatest challenge is to find a safe
28:17place where the boss can lay her
28:23eggs but there's nothing solid here for
28:26the female to lay them on
28:33a nearby shell could be the
28:45solution if only he can move it to the
29:03heavy besides it has a mind of its
29:20crab about out here twice a day the
29:24anemon is swept by tital currents and
29:31opportunities an old plastic
29:38bottle perhaps this will
30:07shell it looks just right but it's a
30:32and he can't move it by
30:46himself so the pair now work
31:31a little adjustment to the anemon
31:33tentacles in order to clear a space for
31:38it and the shell is tucked
31:46in the female lays a safe Nursery at
32:08he has proved himself worthy to Father
32:10her young and he fertilizes
32:17them now he will meticulously tend the
32:29keeping them clean and healthy until
33:03it travels over 8,000 kmet a year riding
33:06on the currents supported by its broad
33:15fins this one may not have eaten for 2
33:25months but the current can carry
33:27promising traces of fatty oils from many
33:30kilometers away and will lead it to its
33:40meal after days of travel the smell of
34:07a dead whale recently struck by a
34:13ship this could be a real Feast but the
34:33sharks 10 times heavier than a
34:38blue a highly possessive around a whale
35:09great whites are eager to feed on energy
35:11rich whale blubber which we now know
35:14forms a major part of their
35:29once the great white has had its fill
35:31smaller sharks like the blue shark
35:34tackle what's left of a
35:45carcass as the oils from this dead whale
35:48spread more widely more and more blue
36:13within days the carcass will be stripped
36:25blubber then no longer kept buoyant by
36:28its oil it will sink Into the Depths
36:35below the blue with its reserves of fat
36:39replenished can now survive for another
36:55eating but most of the creatures come
36:57together for a very different
37:10cuttlefish the largest of all
37:19cuttlefish they live for just one or two
37:29now as the Australian summer draws to an
37:32end they have one last act to
37:45mate but there are over 100,000 males
37:50competing for the arriving females in
38:00among them a giant a true Goliath he
38:04probably weighs about 10
38:09kilos bands of color sweep across his
38:12skin that's how cuttlefish
38:35this smaller male couldn't possibly take
38:48on beside Goliath and under his
38:51protection a female who has just mated
38:58but other Rivals are still
39:04interested it seems a small male
39:09chance the female is now displaying a
39:12white stripe along her side nearest
39:18Goliath it's a clear signal that she no
39:20longer wants to mate with
39:28it's all the encouragement that the
39:53needs he's going to have to use trick
40:11he tones down his colors and Tucks in
40:18arms he's just the right size to mimic a
40:37deceived the small male now displays a
40:41white stripe just like the real female
40:51advances he slips beside
41:08meet by meting with multiple
41:12partners the female ensures the greatest
41:15genetic diversity for her
41:23young the sneaky male leaves
41:34complete so even among giant cuttlefish
41:40seems it's not all about
41:53size in the underwater forests of
41:57Japan the residents of this sunken wreck
42:00are waiting for the summer temperatures
42:16C that for some is the time for
42:35a kind of giant Rass called a cobod
42:51male and in female terms he's
42:54particularly handsome
43:03he's a meter long and weighs 15
43:09kilos much larger than the dimin
43:16female and he is ready to
43:22breed he attempts to meet with her and
43:26with any of the other dozen or so
43:28females that live in his
43:31territory whenever he gets the
43:47chance but females from around 10 years
43:50old take little notice of his
44:22this is because when any large female
44:25reaches a critical body size she can
44:47transformation over just a few months
44:50particular enzymes inside her body cease
44:56and male hormones start to
45:08expands and her chin gets
45:13longer a she has changed into a
45:27and with this comes a change in
45:36temperament the old male who ruled all
45:41here is challenged to a face
45:50off the more bulous the head the more it
46:22opponent the territory has a new ruler
46:38only the largest females transform
46:47way but the change enables them to have
46:50more mates so they will have many more
46:53offspring carrying their jeans
47:02but a new male can't afford to be
47:06complacent inside the body of every
47:10female there is a new mail in
47:23waiting and wave power creates
47:26towering fortresses like these cliffs in
47:29the Arctic home to tens of thousands of
47:37seabirds the faces of the cliffs AR
47:40accessible only from the air and have
47:42plenty of nooks and crannies for those
47:50there but to feed seabirds must still
47:53Master the ocean World Beyond
48:13father he has a mate for
48:23life both share the burden of raising
48:26their weak old chick their puffling who
48:29needs five square meals a
48:33day the parents alternate fishing
49:05when fish stocks are low puffins must
49:08fly as much as 50 km out to
49:11sea to reach the good fishing
49:27once there they plunge into another
49:38world good fishing spots are hard to
49:41come by and they have
49:53gilot like the Puffin there their wings
49:56are short and good for
50:00diving puffins can hold their breath for
50:03over a minute and dive as deep as 40
50:48home after an exhausting round trip of
50:51almost 100 km this puffins nearly made
50:58but there are pirates on this
51:30all around returning parents are being
52:00the skewers long rback Wings make them
52:43puffins must choose their moment
53:26the last desperate burst of
53:59safely home after a 3-hour round
54:09trip where his patient partner is
54:29today their puffling will
54:38eat but where fish numbers are in
54:41Decline many puffins Now find it hard to
54:44get enough food for their
54:48chicks in the changing Seas of today it
54:51can be even harder to be a successful
55:05a kilometer from the surface beyond the
55:14Sun a giant black void larger than all
55:19the rest of the world's habitats
55:29here but not as we know
55:42it alien-like creatures produce dazzling
56:00nearly all animals need to attract mates
56:06Predators this language of light is so
56:09widespread here that these signals are
56:12probably the commonest form of
56:15communication on the entire
56:18planet and yet we still know little
56:46Hunters illuminate themselves and by
56:48doing so attract inquisitive
57:07tooth it has the largest teeth for its
57:13fish there are precious sensors all over
57:16its head and body which can detect
57:18anything moving in the surrounding
57:28it's the midnight Zone's most fucious
57:32fish but prey used light as a
57:40distraction a decoy of luminous
57:52ink down here in this
57:56Blackness creatures live beyond the
58:06time siphonophores are virtually Eternal
58:11they repeatedly clone
58:14themselves some eventually growing
58:53snows continous clouds of organic debris
58:57drift slowly down from
59:05above this is food and a whole variety
59:10of filter feeders depend on
59:46cucumbers the 1% of marine snow they
59:49miss eventually settles on the sea
01:00:21over millions of years it forms a layer
01:00:25up to a kilometer
01:00:30thick it's an empty plane that covers
01:00:34half the surface of our
01:01:02the Deep seabed May at first appear
01:01:07lifeless but it's home to a unique cast
01:01:18toad it is an ambush Predator with an
01:01:37patience this fish has been living for
01:01:40so long here that its fins have changed
01:01:43into something more
01:01:57they help it shuffle about on the sea
01:02:19Flor the flapjack
01:02:27it hovers just above the surface of the
01:02:29mud as it delicately sifts through it
01:02:36worms but it can jet away at the first
01:03:05in the Gulf of Mexico these eruptions
01:03:08also release a super salty
01:03:32it's heavier than seawater and it
01:03:35accumulates in great pools on the seaf
01:03:42floor it's difficult to make sense of
01:03:52site a late of concentrated salt water
01:03:58deep at the bottom of the
01:04:08sea around its margin perhaps even more
01:04:11strangely there is a profusion of
01:04:21life giant muscles that can live for
01:04:24grow for a century or more pack tightly
01:04:27together dwarfing the shrimps and squat
01:04:29lobsters that feed around
01:05:00Cutthroat eels scavengers come to the
01:05:04shores of the Brian Lake in search of
01:05:15edible some even Venture into the
01:05:53spending too long in it can send an ill
01:06:08shock it's only hope is to rise above
01:06:36escape others are not so
01:06:45lucky the Brian embs their
01:06:49bodies and the casualties of
01:06:52decades ACC accumulate around the