- 34 minutes ago
Across open grasslands, a wide array of courtship strategies and tactics is on full display... From the plains of Namibia and the Serengeti to the grasslands of Australia, animals employ diverse strategies to find and defend mates, showcasing a fascinating variety of courtship behaviors...
地球上的草原是进行“求偶博弈”最具挑战性的栖息地之一。这是一片开放的舞台，潜在的伴侣和充满嫉妒的竞争对手会注视着你的一举一动乃至每一次失误。想要在此胜出，必须全力以赴。这里的动物采取的策略既丰富多样又独具特色——既有爱出风头的炫耀者，也有好勇斗狠的格斗士，还有不择手段的无赖与骗子——它们都在竞相角逐那宝贵的交配机会。
地球上的草原是进行“求偶博弈”最具挑战性的栖息地之一。这是一片开放的舞台，潜在的伴侣和充满嫉妒的竞争对手会注视着你的一举一动乃至每一次失误。想要在此胜出，必须全力以赴。这里的动物采取的策略既丰富多样又独具特色——既有爱出风头的炫耀者，也有好勇斗狠的格斗士，还有不择手段的无赖与骗子——它们都在竞相角逐那宝贵的交配机会。
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TVTranscript
00:00THE END
00:32One challenge faces almost all animals on Earth, the need to find a partner.
00:46It's a drama that is played out in every corner of the planet.
00:53For some, it's conducted on an immense scale, others need to put on a show, and for many
01:16years, it involves intense, even lethal battles.
01:26This series will reveal the extraordinary strategies that animals employ to succeed in
01:33the mating game.
01:41Those that win will have a stake in the greatest competition of all.
01:48The creation of a new generation.
02:10Namibia in South West Africa.
02:17An ancient landscape that has shaped the mating game of its residents, ostriches.
02:32The rules of their mating game have been refined and elaborated over some 60 million years,
02:40and are now very well established.
02:46During their breeding season, each flock is dominated by a single male.
02:57His territory, and the females that come with it, is a hard-won asset.
03:06So, his leadership is only challenged by the brave or the foolhardy.
03:19This young male is low in the flock's pecking order.
03:24He's spent five years preparing for this moment, and now he needs to breed.
03:32The resident females seem interested.
03:41He starts to show off.
03:46And their attention encourages him.
04:05But the current leader does not tolerate competition.
04:25The kick of an ostrich is powerful enough to kill a lion.
04:32And the young male is risking an end to his breeding season before it's even started.
04:55In a matter of moments, the young challenger has been cursed out of his flock.
05:03It's a disastrous start to his campaign.
05:07But it comes with a valuable lesson.
05:12Out here in the open, the mating game is exposed for all to see.
05:35The young male now faces a major challenge.
05:41The young female now faces a major challenge.
05:42There are not many ostriches on these dry plains, and females are hard to come by.
05:48It could take him several months to find one.
06:04He does, however, have a way of bringing them to him.
06:19He inflates a sac in his throat and produces a boom that carries for miles.
06:29And it attracts unaccompanied females.
06:42But that is the easy bit.
06:46Female ostriches are very choosy.
06:51With the largest eyes of any land-living animal,
06:54they assess his every detail.
06:58The pinkness of his shins.
07:00The shininess of his black feathers.
07:05Both indicate his sexual quality.
07:09But he has yet to pass a crucial test.
07:16The females lead him on a chase, testing his stamina.
07:22And they can run at speeds of 40 miles an hour.
07:29All he has to do is to keep up.
07:43One of the females slows.
07:46And once again, he tries to win her over.
07:55But again, she seems indifferent.
08:06Now, he has only one trick left.
08:32At last, he seems to be getting some attention.
08:47She flicks her wings, a sign that she is impressed.
08:52So, with little to lose, cautiously, he performs his final trick.
09:04It's not perfect.
09:10But he gives the performance of his life.
09:42And he goes around much work...
09:43It's not perfect, ghost.
09:49With that achieved, he will now go on and mate with several more females before the season
09:56is over. Provided that is, he can maintain their interests.
10:07He now has a final task. He must take every female with whom he mates this season to his
10:14chosen nest site and there incubate all their eggs for the next two months. Only if they
10:22hatch will he know that he has truly succeeded in his mating game.
10:36Where grass grows abundantly, mating, for many, is rather more competitive.
10:56This zebra stallion has spent several years assembling a group of females, his harem, and
11:03he'll do anything he can to retain them all.
11:10Some of his mares are already pregnant, and he leads them on the never-ending search for
11:15food.
11:23Every March, they come here to the Serengeti, one of the most extensive natural grasslands
11:31left on Earth.
11:37Such rich grazing attracts herds 30,000 strong.
11:48His family has good reason to join this huge assembly.
11:55There is safety in numbers and predators here are awaiting them.
12:06Hyenas.
12:19Small harems are the most at risk.
12:37The herds will provide the safety that the stallion needs.
12:42And right now, his family is particularly vulnerable.
13:03Here, his newborn foals can get a good start in life.
13:18Soon after birth, their mothers become ready to mate again.
13:25But being in a big herd causes a problem for the stallion.
13:38Bachelor males are quick to detect the scent of a newly receptive mare.
13:47And they will try to separate one from the rest of his harem, whether she is willing or
13:52not.
14:06If a stallion doesn't drive off the bachelors, his group will be broken up in a matter of
14:11five minutes.
14:21But if he's going to keep his family together, he will have to fight.
14:44The well-placed bite to the bottom is enough to see off weaker rifles.
14:52But with challenges coming from all sides, he's in danger of losing control.
14:57Yep, his
14:57gah-gah-gah-gah-gah-gah-gah.
15:24Oh, no, no, no, no, no.
15:52His family is still together, for now.
15:57But his right to breed isn't guaranteed.
16:01His females will still have the deciding say in that matter.
16:10Competition between males for a mate is common throughout the natural world.
16:18But females may also play a deciding part in the mating game.
16:24One such is so efficient at doing that, that her species has become one of the most successful of any
16:32on the planet.
16:35Here on the grasslands of Africa, their castles of clay are a familiar sight.
16:42Each one is ruled by an extraordinary, all-powerful queen.
16:50Her domain can stretch for many miles underground and is maintained by armies of her subjects,
16:57most of whom implicitly obey her instructions but never even meet her.
17:12Everything in this community is under her control.
17:18She can live for 50 years longer than any other insect in the world.
17:25Meet the termite queen.
17:40Her devoted partner, the king, has been at her side throughout her life.
17:46He mates with her frequently, but his role is limited to that.
17:51It is his gigantic queen who dominates the colony.
18:06Her bloated body contains huge ovaries which produce eggs non-stop.
18:17She lays one every three seconds, 24 hours a day, for 25 years.
18:24A productivity unmatched in the natural world.
18:31All in the colony are her offspring, and all are dependent on her success.
18:39They clean her tirelessly and keep her well fed.
18:45Some remove the eggs and store them, a seemingly never-ending job.
18:57Some remove the egg.
18:58In her lifetime, she will produce over a quarter of a billion offspring.
19:11As each egg emerges, it's taken away to another chamber.
19:16Here, the workers toil to create the perfect conditions for their development.
19:25Some chambers serve as gardens.
19:30Here, the workers cultivate balls of white fungus with which to feed the queen.
19:47But not all young termites remain equal.
19:53Their future will be determined by the queen.
20:00In response to the needs of the moment, she will produce chemical instructions
20:06that determine the role each of her offspring will play in the community.
20:15And once a year, she changes the behavior of the entire colony.
20:26As the rainy season approaches, she orders her workers to open new gateways in the outside walls of their castle.
20:35They are preparing the most important and dramatic happening in their year.
20:49Exactly why the rains trigger this event is still unknown.
20:53But it will not begin without them.
21:02What happens next occurs on only a few days in a year.
21:08But the future of her entire kingdom depends on it.
21:15As a consequence of a chemical signal from her, some of her subjects have developed wings.
21:22Each of these winged termites is a potential queen or king.
21:31And one morning at first light, they emerge in millions,
21:38attempting to get as far away as possible and start their own community.
21:59But their journey is beset by danger.
22:03Such a multitude of edible insects does not go unnoticed.
22:25The emerging in these vast numbers is part of termite strategy.
22:30The loss of a few thousand individuals amongst millions is insignificant.
22:38Eventually, even the greediest predators will have had as much as they can eat.
22:47The surviving termites, males and females, find partners, shed their wings,
22:55and each partnership then digs a new colony together.
23:01So, if things go well, more clay castles will appear on the African plains.
23:13A lifelong partnership between male and female can certainly lead to great rewards.
23:20But in fact, such a simple strategy is rare.
23:26Delaying finding a mate until one reaches one's physical prime is a more common tactic.
23:32But it does have its problems.
23:37These are the meadows of southern Australia.
23:42Here, sheer physical size can make a significant difference.
23:52Male grey kangaroos battle for access to the females.
24:00The biggest nearly always wins.
24:03As a result, the males have become very big indeed.
24:09At two and a half meters tall, they're more than twice the size of the females.
24:26These battles are nearly always won by the biggest male.
24:38But it will be the female who will decide exactly when he will be allowed to claim his reward.
24:45A female can conceive at any time, so there is no rush as far as she is concerned.
24:54But a male kangaroo has to fight whenever he is challenged, so he is keen to mate just as soon
25:01as he can.
25:04The longer the delay, the greater the chance that another male will displace him.
25:16Rival males show off to make clear how very big they are.
25:26So the victor keeps her close by him while he still has the upper hand.
25:40She, however, continues to explore her options.
25:51No matter what the victor does to impress her,
25:58she is still reluctant to commit.
26:05Things are taking a little longer than he might like.
26:10After days of unsuccessful courting, she leads him to the edge of the meadow.
26:19And here, there are others who keep an eye on what is happening.
26:26Less physically impressive males lurk out of view, waiting for a female to lose her suitor.
26:36They just need a distraction.
26:40Another large male enters the competition.
26:46He's just as big as the first one, so if he is to win the female, he'll have to fight.
26:58And while both of them are preoccupied by battle,
27:07she looks elsewhere.
27:24This smaller male, out in the open, would stand little chance of winning a mate.
27:35But while the big boys battle, she is willing to accept him.
27:48Sneak mating like this accounts for only a small proportion of kangaroo pregnancies.
27:57But in a grassland dominated by a few particularly large males,
28:02sneaky strategies ensure the genetic diversity of the next generation.
28:28But if you live in the entangled vegetation on the grassland floor,
28:34it's possible to use rather defiantly available items.
28:47The male nursery web spider, he's hunting, he actively stalks his prey, and the grass
29:03provides him with excellent cover.
29:27But he's not going to eat this catch himself.
29:36Instead, he's going to give it to someone he has not yet met.
29:43First, he carefully gift wraps his capture.
29:48Presentation is going to be very important.
29:54Once satisfied with the appearance of his parcel, he starts searching for someone to give it to.
30:04Lines of silk amongst the grass stems are a promising lead.
30:17And there are signals coming from the other end.
30:21The female nursery web spider.
30:27It seems promising.
30:37But he must be careful.
30:39She is, after all, a killer, just as he is.
30:51And she seems quite hungry.
30:57She accepts his gift and begins to eat it.
31:07For a first meeting, things seem to be going very well.
31:20Well enough, anyway, to make his hair stand on end.
31:31While she is busy eating, he gets ready for action.
31:40He starts to transfer his sperm to her using a specialized sack on his foreleg.
31:50Both sides seem content.
31:53She gets a meal, he gets to mate.
31:59But the exchange among spiders isn't always so equal.
32:06A male nursery web spider will attempt to mate with as many females as he can.
32:13His biggest problem is finding enough food to satisfy them all.
32:24Most spider hunts, like the hunts of most predators, end in failure.
32:37So this male spider cheats.
32:43He starts by picking up someone else's leftovers.
32:48A dead fly.
32:53Providing it's well wrapped, she might never know.
33:05But there's only one way to find out if it's acceptable.
33:17Amazingly, it works.
33:23Encouraged by this success, he does something exceptionally devious.
33:29He wraps up a flower.
33:34It's not even food.
33:39Such extreme deception is rare.
33:46And it doesn't always work.
33:49This male, however, seems to have mastered the trick.
33:58Now his success is limited only by the number of gifts that he can collect.
34:06With a strategy that is clearly effective,
34:09he tries almost anything that looks remotely suitable.
34:20Not all nursery web spiders can pull off this trick.
34:25But for those that can, the prize is worth the effort.
34:32Or in this case, the lack of it.
34:41Deception is a risky strategy.
34:44Especially out in the open, where it can more easily be detected.
34:51So some males work together to put on a show.
35:03In Northern Finland, groups of male ruffs gather on communal display grounds known as leks.
35:13They rely on spectacular neck feathers to impress a partner.
35:24But fine feathers by themselves are not enough.
35:32Empty leks, like empty dance floors, rarely entice the opposite sex.
35:38The more males there are, the more attractive they will be.
35:44So the locals accept visiting males.
35:52The visitors have a distinct white ruff.
35:56And they travel between leks, looking for the best mating opportunities.
36:02So with both visitors and locals here, this lek has become very conspicuous.
36:13The males advertise the richness of the choice on offer by leaping into the air.
36:23It gives them a good chance of being seen by females flying overhead.
36:40A flock of females descends for a closer look.
36:48The male's strategy is clearly working.
36:54And now, they start to show off their extravagant ruffs.
37:09The females now have plenty of males to choose from.
37:21But any attempt by the white neck visitors to do more than display is quickly dealt with by the lek
37:28owners.
37:40With only a few females on the lek, the locals soon squabble amongst themselves.
37:59Some do find a mate.
38:03As do some of the visitors.
38:08But many do nothing but fight.
38:16Unobtrusively, however, something else is going on.
38:24Meet a fader.
38:27A male ruff wearing the plumage of a female.
38:34The only known example of cross-dressing in the bird world.
38:42A fader avoids competition since all the other males think he's a female.
38:51So while the other males continue to fight it out, the fader moves in.
39:12Only 1% of the male population are faders.
39:21But it proves that in gatherings where male display is important,
39:26there is still room for a different approach.
39:42Assembling in really large herds, like those that appear on the open savannas of Kenya,
39:48can seriously complicate the mating game.
39:52They attract the greatest concentration of predators in the world.
40:17Here, you have to keep your eyes peeled.
40:25And this young male Topey is doing just that.
40:35His excellent eyesight enables him to spot approaching predators.
40:43And his alarm calls warn others of the dangers lurking in the grass.
40:57But a sentry also wants to mate.
41:05So eventually he abandons his post
41:09and follows the other males to the traditional display grounds.
41:20Now, with no one to give warning of predators,
41:24the journey is becoming dangerous.
41:46On arrival, the young male's problems become evident.
41:55The females tend to look for males in the centre of the display ground.
42:00So that is the place to be.
42:15But he has to battle with rivals even before he gets there.
42:26The stakes in the mating game now get even higher.
42:44Females arrive in a group.
42:50A female Topey is fertile for only one single day in the whole year.
42:57So it's vital that he makes a good impression right now.
43:03He tries a ritualized trot that demonstrates his physical fitness.
43:16Females seem to take no notice.
43:18But the females seem to take no notice.
43:23He needs to do something else.
43:31He tries driving his horns into the ground as others are doing.
43:43The effect is certainly eye-catching.
43:49But will it make any difference?
44:13Still no takers.
44:24But now he is attracting the wrong sort of attention.
44:36His final tactic is less obvious.
44:39He actually exploits the presence of predators.
44:46As a female comes into view, he snorts a predator alarm call.
44:53It stops the female in her tracks.
44:59It's a false alarm, but it delays her just long enough to give him a chance.
45:12And that is all he needs.
45:22His success gives him a fresh swagger.
45:33But in mating with so many females, he exposes himself to danger.
45:44Since arriving a few weeks earlier, he has barely stopped to eat or drink.
45:52His mating exertions have left him exhausted.
46:05With few males acting as sentries, this is neither the time nor the place to drop your guard.
46:12This is the end of the time.
46:12To be possessed, this is not the one.
46:17I have never seen anything in the future.
46:39The power of superpowers is a creature.
46:42It's more than a match for a single adult cheetah.
46:47But there are two.
46:51And now three.
47:08Such is the desire to breed that some on this grassland pay for the chance to do so with their
47:15lives.
47:25But those who manage to complete the act of mating will have left a legacy within the herd.
47:44The mating game begins with finding a partner.
47:49For many, the act of mating brings it to an end.
47:55But for some, that isn't the whole story.
48:02After 40 days of incubation, ostrich parents have to take on their final responsibilities.
48:12Chicks, just a few days old.
48:23The timing of their parents' mating couldn't have been better.
48:31Rain has brought plenty of food to the arid grasslands, and that is what the chicks must have if they
48:38are to survive and grow.
48:42So the responsibilities of these adults are still by no means over.
48:54Winning the mating game can have its consequences.
49:04And for some, they can be the greatest challenge of all.
49:33To film the mating game, crews traveled across the world to gain an intimate understanding of animal creation in the
49:39world.
49:39animals and their habitats.
49:49Oh, my God, there's a baby caiman in his mouth.
49:53Over two and a half years, teams worked alongside wildlife experts,
49:58often going to extreme lengths to capture the behaviors on camera.
50:02It's unbelievable what's happening here in this forest.
50:07What they uncovered was beautiful and surprising
50:11and revealed the true complexity of the strategies
50:15that animals employ to win the mating game.
50:26One of their greatest challenges involved predicting
50:29when ostriches will begin their breeding
50:31in the desert grasslands of Namibia.
50:36It's a behavior that cameraman Martin Kolbeck
50:40has spent years trying to understand.
50:42I'm pretty excited.
50:44I just want them to get on with their mating game.
50:50Martin's experiences tell him, in this part of the world,
50:54ostriches have to time their breeding to perfection.
50:58We think that the breeding is just about to kick off,
51:02but what hasn't happened yet is that the ostriches haven't split up
51:06and dispersed to look for nest sites.
51:08And that's when the males start to do their territorial chasing
51:12and displaying to each other.
51:15The birds must begin their breeding in advance of the annual rain.
51:19It's a gamble that ensures that there will be enough food for their chicks
51:23when they eventually hatch.
51:27It means that the film team must also second-guess the timing of their trip.
51:33As with many places in the world these days, the weather patterns here in Namibia
51:38are so unpredictable.
51:39It's had drought for five years.
51:41And you can look around and it's really, really dry and really, really barren.
51:45And there's a slight worry within the camp that, you know, with this drought
51:49and with this unpredictable weather, that there's just no real trigger, as it were,
51:54for the ostriches to do their thing.
51:57The more they search, the greater the sense of unease at the lack of activity.
52:10Aerial reconnaissance by the team uncovers further evidence
52:14that this landscape is under duress.
52:18Quiver trees have evolved to cope with long periods without rain,
52:23but even they have succumbed to the drought.
52:26I can imagine what this place must have looked like 15, 20 years ago.
52:31It's upsetting.
52:33I'm actually really upset.
52:35You know, you come here thinking,
52:37oh, wow, amazing quiver tree forest,
52:39and you get here and you just see this devastation.
52:43I'm upset.
52:44I'm really, really, like, as in truly upset.
52:49It was like, like you said, these trees are older than us.
52:53You know, trees are older than you, myself, and Gad combined,
52:59and they're just lying here.
53:01Dead.
53:01It's done for.
53:12Bad situation to be in.
53:16As the weeks pass, there's still no sign of the rain the ostriches so desperately need.
53:23They should be establishing their territories.
53:27They should be digging their nests.
53:29The males should be fighting.
53:31But they're not.
53:34In the year that Martin was here,
53:37Namibia experienced the worst drought in 90 years.
53:43In these conditions, the ostriches seemed to sense
53:47that any attempt at breeding would end in failure.
53:52The team left empty-handed.
54:00The following year, the mating game returned with a new team
54:04and renewed hope that the rains might eventually arrive.
54:10And what they encountered from the start took them by complete surprise.
54:25With this much foreplay on display,
54:27it's clear the ostriches are in a very different mood.
54:31Far distance, we just saw a male definitely doing what we wanted to do.
54:37So we're just now going as fast as we can over here,
54:40hoping they're going to keep going.
54:41He's twisting, he's twisting, he's twisting.
54:43He's twisting, he's twisting.
54:43Oh my god, she's twisting.
54:47Yeah, that's a good angle.
54:49He's running.
54:50Okay, let's get ahead of this one.
54:54With the males now violently competing for females,
54:58their mating game has literally kick-started.
55:02Amazing thing to see.
55:04Just incredible.
55:06Is there a round of half hours appropriate?
55:08Yes.
55:08Yeah.
55:09Well done.
55:10Good job.
55:11Jeez.
55:12Thank goodness for that.
55:14How long was that?
55:15Anyway, it's not that long.
55:16It's just the intensity of it, isn't it?
55:21More surprising, with still no rain but clouds building on the horizon,
55:25the ostriches begin to launch into their finale.
55:30Oh, yes.
55:31Yes.
55:32No, she's...
55:37Yes.
55:39Well done, Steve.
55:46So it's all going ahead, and we were trying to work out why that is,
55:51what's the difference, because there's still been no rain at all,
55:54been a few clouds, but we've just seen that the forecast for next Monday,
55:58that's a week away, this rain forecast.
56:01So, you know, maybe they somehow know that.
56:04I don't know how they do that, but maybe they know that there is,
56:07it's going to be a good rain year.
56:09In the coming weeks, after five years of waiting, something remarkable happened.
56:17The desert plains received a much-needed downpour.
56:24It seems the ostriches got their timing right, after all.
56:34Next time, the largest of all habitats.
56:39Oceans.
56:41Where life first invented the mating game.
56:49And where the challenge of simply finding a mate
56:52sparks some of the greatest battles on Earth.
57:00It's a lot of great possibilities.
57:29If not today, the fire should be best.
57:29You
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