David Attenborough: The Sound of Nature Episode 2(EN)Subtitles

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1 00:00:10 (ANIMALS HOOT AND CHATTER)
2 00:00:15 The natural worldis filled with sound.
3 00:00:19 (THUNDERCLAP)
4 00:00:21 But so far,we've been hearing only part of it.
5 00:00:24 (CHITTERS)
6 00:00:26 (GROWLS)
7 00:00:28 (CHIRPS)(BUZZES)
8 00:00:30 New audio technology now capturessounds that we can't even hear.
9 00:00:36 (DEEP, RESONANT RUMBLING)
10 00:00:42 For some animals,sound is the key to finding a mate...
11 00:00:46 (CHIRPS)
12 00:00:50 ...to impress others...
13 00:00:52 (CHIRPING, WHISTLING)
14 00:00:55 (RUMBLING, POPPING)
15 00:00:58 ...and to warn off the competition.
16 00:01:01 (BELLOWS)
17 00:01:11 (ANIMALS CHIRP AND CALL)
18 00:01:23 (TWEETS)
19 00:01:26 (CHIRPS, CHITTERS)
20 00:01:37 (SINGS)
21 00:01:40 (BIRDS CHIRP AND WHISTLE)
22 00:01:48 (SINGS, CHIRPS)
23 00:01:51 A British woodland in spring.
24 00:01:54 The air is filledwith the sound of bird song.
25 00:01:59 It's a sound that bringsa lot of people a lot of pleasure...
26 00:02:04 including me.
27 00:02:06 And all these birdsare singing for two reasons...
28 00:02:11 one - to establish a territory,
29 00:02:14 and two - to attract a mate.
30 00:02:18 (BIRDS SING AND CHIRP)
31 00:02:23 Song travels wellin an open woodland.
32 00:02:28 But making yourself heard can be morechallenging in a noisier environment.
33 00:02:35 And there is one creature herethat has risen to that challenge.
34 00:02:46 This delightful little birdis a white-throated dipper.
35 00:02:52 For most birds of its size,
36 00:02:54 living beside streamsis rather a dangerous place.
37 00:03:03 Feathers, when they are wet,on a bird of this size,
38 00:03:05 aren't much good for flying,
39 00:03:08 but the dipperknows how to deal with that.
40 00:03:13 As it searches for foodbetween the rocks,
41 00:03:16 it stops frequently to cover itsfeathers with oil from a preen gland
42 00:03:21 so that they stay waterproof and dry.
43 00:03:27 Reaching your food underwater...
44 00:03:30 is just one of the problemsfaced by the dipper.
45 00:03:33 Another is how do you send messages
46 00:03:35 above the noise of the fast-flowingstream by which you live?
47 00:03:41 But the dipper has a wayof dealing with that as well.
48 00:03:46 It's the breeding season...
49 00:03:49 ...and this male uses his voiceto find a partner.
50 00:03:54 (WATER RUSHING, SOFT CHIRPING)
51 00:03:59 To our ears,his singing can hardly be heard
52 00:04:02 above the sound of the water.
53 00:04:07 But eliminatingthe sounds of the river
54 00:04:11 reveals a surprisingly complexand melodious song.
55 00:04:15 (ARTICULATED CHIRPS)
56 00:04:25 Most of the dipper's notesare higher-pitched
57 00:04:28 than the noise of the water.
58 00:04:30 (MELODIC CHIRPING)
59 00:04:34 This allows othersto hear his song more easily.
60 00:04:43 He has attractedthe attention of a female.
61 00:04:47 (ELABORATE CHIRPING)
62 00:04:56 Only males in peak conditioncan sing complex tunes like this.
63 00:05:07 (SINGING)
64 00:05:10 His song has impressed,
65 00:05:12 and his new mate will stay with himfor the rest of the year
66 00:05:16 and help him defend this territory.
67 00:05:18 (COMPLEX CHIRPING)
68 00:05:33 Six weeks later,and the pair have been busy.
69 00:05:44 Concealed behind the waterfallis their nest.
70 00:06:01 To ensure a steady supply of foodfor the chicks,
71 00:06:05 the pair have to defendtheir stretch of river from others.
72 00:06:10 And its their songthat acts as a warning to rivals.
73 00:06:14 (SINGS)
74 00:06:23 Together,they present a united front.
75 00:06:27 (SINGING)
76 00:06:35 For any intruders,the message is loud and clear.
77 00:06:39 (ELABORATE CHIRPING AND SINGING)
78 00:06:51 Keeping the chicks well-fedis crucial,
79 00:06:54 and not just for their growth.
80 00:06:58 It's needed to developthe part of the brain
81 00:07:01 responsible for learning song.
82 00:07:06 So, they will, one day,become proficient singers,
83 00:07:09 like their parents.
84 00:07:17 Two weeks on, and all three chickshave fledged successfully.
85 00:07:28 (CHIRPING)
86 00:07:30 These youngsters have hadthe best possible start in life...
87 00:07:36 ...thanks to their parentsand their song.
88 00:07:39 (SINGS)
89 00:07:47 When it comes to finding a mate,
90 00:07:49 power, not melody,is sometimes needed.
91 00:07:56 (HIGH-PITCHED CALLS)
92 00:08:04 (RESONANT CALLS AND GRUNTS)
93 00:08:13 Autumn inthe Rocky Mountains of Canada.
94 00:08:17 (SNORTS)
95 00:08:23 (HIGH-PITCHED CALL)
96 00:08:32 This bugling call of the elkmarks the change of season...
97 00:08:37 and the beginning of the annual rut.
98 00:08:48 (DEEP VOCALISATIONS)
99 00:08:53 This bull is in his prime,and over the next six weeks,
100 00:08:57 he will push himself close to deathin order to mate.
101 00:09:07 The females will only acceptthe largest and strongest male.
102 00:09:15 And his success will depend onthe power of his voice.
103 00:09:23 Stretching his vocal chords,
104 00:09:25 he produces a high-pitched shriekthrough his nose.
105 00:09:34 It travels over a mile...
106 00:09:36 and announces his presenceto distant females.
107 00:09:41 (BELLOWS)
108 00:09:50 At the same time,he makes a guttural groan...
109 00:09:53 (RESONANT BELLOW)
110 00:09:57 ...which signals his size and strengthto nearby males.
111 00:10:03 The deeper his voice,the bigger and stronger he is.
112 00:10:11 And he backs it upwith a physical display.
113 00:10:28 (BELLOWS, CALLS)
114 00:10:37 His goal is to gatheras many females as possible...
115 00:10:40 to ensure that his genesare the ones that are passed on.
116 00:10:45 (BLEATING)
117 00:11:04 (HIGH-PITCHED CALL)
118 00:11:06 (DEEP, RESONANT VOCALISATIONS)
119 00:11:10 Now he switchesto a different call...
120 00:11:13 (VOCALISATION CONTINUES)
121 00:11:16 ...a low 'glunking' soundto encourage the females to join him.
122 00:11:25 A successful bull can attractup to 20 females in one season.
123 00:11:30 (DEEP VOCALISATIONS)
124 00:11:34 Chemical cues,detected with his tongue,
125 00:11:36 tell him which cows are fertile.
126 00:11:51 But retaining so many femalesis easier said than done.
127 00:11:55 (HIGH-PITCHED CALL)
128 00:12:05 A rival enters the arena.
129 00:12:10 (BELLOWING)
130 00:12:20 Their bugles signalthat they are equally matched.
131 00:12:26 There's only one way to settle this.
132 00:12:28 He must stand his groundor surrender his females.
133 00:13:00 These battles can resultin serious injury, even death.
134 00:13:07 (HIGH-PITCHED CALL)
135 00:13:22 For the moment, at least,
136 00:13:24 his legacy is secure.
137 00:13:36 (RUMBLING)
138 00:13:41 (RUMBLING)
139 00:13:46 On the vast grasslands of Alberta,
140 00:13:49 it takes teamwork to get noticed.
141 00:13:52 (COOING)
142 00:13:56 (RESONANT RATTLING)
143 00:14:00 Every spring,
144 00:14:02 male sharp-tailed grouse gatheron traditional breeding grounds...
145 00:14:07 (RATTLING)
146 00:14:09 ...practising for their most importantperformance of the year.
147 00:14:14 (CLUCKING, RATTLING)
148 00:14:16 And they have a remarkable array
149 00:14:19 of musical instrumentsat their disposal.
150 00:14:26 Feet are stamped,
151 00:14:28 and tail feathers rattled,to produce a rhythmic beat.
152 00:14:38 A low cooing sound,
153 00:14:40 amplified by inflatable air sacs,
154 00:14:43 provides the accompanying tune.
155 00:14:47 (CLUCKING, RATTLING)
156 00:14:48 And it's all to attract the attentionof the females.
157 00:14:54 The more males, the louder and moreimpressive their performance.
158 00:14:58 (COOING, RATTLING)
159 00:15:01 But sometimes, tensions boil over.
160 00:15:15 (CLUCKING)
161 00:15:22 They need to stop squabblingand work together.
162 00:15:25 (RATTLING)
163 00:15:48 Their combined song and dancehas attracted a female.
164 00:15:54 (CLUCKING)
165 00:15:58 Time for the synchronised finale.
166 00:16:07 They all freeze.
167 00:16:11 She takes the opportunityto assess each male.
168 00:16:18 (RATTLING RESUMES)
169 00:16:33 Now she's looking forthe fastest tail rattle.
170 00:16:43 And a soundlike the popping of a cork...
171 00:16:45 (POPPING)
172 00:16:51 ...which females find irresistible.
173 00:16:56 Their display will help her findthe fittest male in the group.
174 00:17:02 And this onehas caught her attention.
175 00:17:07 But not everyoneis sticking to the dance routine.
176 00:17:13 A young, over-enthusiastic male
177 00:17:16 is ruining the performancefor everyone.
178 00:17:19 (CLUCKS)
179 00:17:26 She's seen enough.
180 00:17:28 And she's off.
181 00:17:32 (RATTLING)
182 00:17:36 Today didn't go as planned.
183 00:17:39 (CLUCKS)
184 00:17:41 But tomorrow, they'll havethe chance to do it all over again.
185 00:17:48 While grousebenefit from joining forces,
186 00:17:52 others must find a wayto stand out from the crowd.
187 00:17:56 (HIGH-PITCHED SHRIEKS)
188 00:18:01 In the deserts of Arizona,
189 00:18:03 temperatures can soarabove 40 degrees Celsius.
190 00:18:10 Rain hasn't fallen herefor several months.
191 00:18:19 But things are about to change.
192 00:18:22 (THUNDER RUMBLES)
193 00:18:26 (WIND HOWLS)
194 00:18:28 (CRACKLES)
195 00:18:31 (THUNDERCLAP)
196 00:18:50 (THUNDERCLAP)
197 00:19:05 Within hours,the rains flood the ground...
198 00:19:08 and temporary pools appear.
199 00:19:16 The thunder sends shockwavesthrough the ground...
200 00:19:20 (THUNDERCLAP)
201 00:19:27 ...which trigger an annual uprising.
202 00:19:45 Breaking freefrom their underground vaults,
203 00:19:47 desert frogs and toadsemerge to breed.
204 00:19:52 (CROAKS)
205 00:19:57 (CACOPHONOUS CROAKING)
206 00:20:00 They will have just one or two nightsto find a mate.
207 00:20:04 And there are hundreds of frogsin this one pool.
208 00:20:08 (CROAKING CONTINUES)
209 00:20:16 Not only that,
210 00:20:18 at least five different species areall trying to make themselves heard.
211 00:20:25 (CROAKS)
212 00:20:27 How is a female to find a maleof her own kind?
213 00:20:32 (CROAKING)
214 00:20:35 The answer, it seems,lies in their voice.
215 00:20:42 Each species hasits own distinctive call.
216 00:20:47 (CROAKING, CHIRPING)
217 00:20:53 (DEEP, RATTLING CROAK)
218 00:20:54 (GROANS)
219 00:20:56 And now we can seejust how the females do it.
220 00:21:03 A specialised acoustic camerashows sounds
221 00:21:06 of different frequenciesin different colours...
222 00:21:09 (GROANING, CROAKING, CHIRPING)
223 00:21:14 ...and reveals that each speciesfavours different notes and rhythms,
224 00:21:19 allowing females to pinpoint malesof their own kind.
225 00:21:32 When it comes to mating,
226 00:21:34 it generally makes senseto stick with your own species.
227 00:21:40 But desperate timescan lead to desperate measures.
228 00:21:46 On the other side of the valley,
229 00:21:48 the rains have been less plentiful,
230 00:21:50 and the pools hereare dangerously shallow.
231 00:21:54 (CROAKING)
232 00:21:57 This plains spadefootneeds her young to develop quickly
233 00:22:01 before the water disappears.
234 00:22:06 It's a race against the clock,
235 00:22:08 and the calls oftwo different species are deafening.
236 00:22:11 (CROAKING, CHIRPING)
237 00:22:27 She tunes into the callsof her own kind of male.
238 00:22:32 (CROAKS RHYTHMICALLY)
239 00:22:43 But surprisingly, she sidesteps them.
240 00:22:54 The pulsing callof a Mexican spadefoot
241 00:22:58 has attracted her attention.
242 00:23:05 He belongs to a different species,
243 00:23:07 but, remarkably, she can stillmate with him if she so chooses.
244 00:23:14 And in this case, she does...
245 00:23:17 and for a specific reason.
246 00:23:22 His tadpoles will develop fasterthan those fathered by her own kind
247 00:23:28 and give her young a chance to reachmaturity before the pond dries up.
248 00:23:35 It's an unusual practice...
249 00:23:37 but an effective one.
250 00:23:39 And in an unpredictableand warming climate,
251 00:23:43 solutions like thismay help ensure their survival.
252 00:23:52 But her decision comes at a price.
253 00:23:58 Only female offspring producedfrom this liaison will be fertile.
254 00:24:05 But she's ensured that at leastsome of her genes are passed on.
255 00:24:12 (RUMBLING)
256 00:24:17 (RUMBLING)
257 00:24:22 Frogs aren't the only ones
258 00:24:24 to use their voiceunder the cover of darkness.
259 00:24:28 (RESONANT HUMMING)
260 00:24:36 On the Pacific Coastof North America,
261 00:24:39 the night air resonateswith an eerie hum.
262 00:24:48 It's a soundthat baffled people for years.
263 00:24:59 It coincides with the arrivalof a fish from the open ocean...
264 00:25:09 ...a plainfin midshipman.
265 00:25:15 For the next three to four months,
266 00:25:17 this male will risk his lifein the shallow intertidal zone.
267 00:25:24 He's searching for a suitable spotto make a nest.
268 00:25:41 This one looks ideal.
269 00:25:45 Time for some housekeeping.
270 00:26:08 One final mouthful...
271 00:26:14 ...and it's complete.
272 00:26:19 But the femalesare still in deeper water.
273 00:26:23 He needs a wayof attracting their attention.
274 00:26:28 The onset of night is his cue.
275 00:26:32 (DRONING HUM)
276 00:26:38 By vibrating musclesattached to his swim bladder,
277 00:26:42 he produces a low-frequency hum
278 00:26:45 that travels well through water.
279 00:26:47 (HUMMING CONTINUES)
280 00:26:52 And he's not alone.
281 00:26:54 (CHORUS OF HUMMING)
282 00:26:57 He's joined by dozens of others.
283 00:27:10 The sound reachesa staggering 110dB -
284 00:27:15 as loud as a lion's roar...
285 00:27:18 (HUMMING CONTINUES)
286 00:27:20 ...giving rise to the mysterious drone
287 00:27:23 that once puzzled the peoplewho lived on these shores.
288 00:27:28 (DRONING HUM)
289 00:27:36 This sound is loud enoughto be heard by the females.
290 00:27:46 Guided by the hum,a female arrives, swollen with eggs.
291 00:27:52 (DRONING HUM)
292 00:27:54 The harmonics producedby each male are slightly different,
293 00:27:57 like a sonic fingerprint,
294 00:28:01 and help him stand outfrom the crowd.
295 00:28:08 His song has drawn her this far,
296 00:28:11 but now his nest is under scrutiny.
297 00:28:19 It's to her liking.
298 00:28:24 Hovering upside down,
299 00:28:26 she lays her eggs on the roof.
300 00:28:43 The next morning, she has gone.
301 00:28:48 The male alone will protect the eggsfor the next three months.
302 00:28:55 During this time, he won't feedor leave them unattended.
303 00:29:03 A crab... looking for a snack.
304 00:29:07 (GROWLS)
305 00:29:10 (GRUNTS)
306 00:29:12 He sends a warning growl...
307 00:29:15 (GROWLS)
308 00:29:17 (GRUNTING)
309 00:29:22 ...and a grunt.
310 00:29:24 (GRUNTING)
311 00:29:26 The crab finally gets the message.
312 00:29:32 But the biggest challenge he faces
313 00:29:35 comes with the daily changingof the tides.
314 00:29:50 Midshipman fishare adapted to breathe air,
315 00:29:54 but the low tideleaves him defenceless.
316 00:30:03 With no means of escape,it's now down to luck.
317 00:30:33 On this tide, he's made it.
318 00:30:37 If he and his eggs can survivethe hazardous months ahead,
319 00:30:41 he will have helped father the nextgeneration of midshipman singers.
320 00:30:50 Sound travels well underwater.
321 00:30:56 On land, however,it is often deflected,
322 00:30:58 or absorbed, by the surroundings.
323 00:31:03 Thick rainforestspose a particular challenge.
324 00:31:08 (HOOTING, CHITTERING)
325 00:31:10 The dense vegetationacts as a sound barrier...
326 00:31:15 ...and despite the many voices,
327 00:31:17 most messages don't travel far.
328 00:31:22 (DEEP CHIRPING)
329 00:31:26 (HOOTS)
330 00:31:32 (CHIRPS)
331 00:31:35 (CHIRPS SQUEAKILY)
332 00:31:38 (CHITTERS)
333 00:31:42 (HIGH-PITCHED CROAKS)
334 00:31:49 In the forests of Southeast Asia,however, there is one animal
335 00:31:53 that knows exactly howto make its message heard...
336 00:32:02 ...a yellow-cheeked crested gibbon.
337 00:32:07 He moves to a higher positionwhere the canopy is less dense.
338 00:32:14 (HIGH-PITCHED HOOTING)
339 00:32:29 Unobstructed by trees,
340 00:32:31 his call carriesfor over a mile across the forest.
341 00:32:36 (HIGH-PITCHED HOOTING CONTINUES)
342 00:32:40 And he's not alone.
343 00:32:42 His partner and baby are close by.
344 00:32:46 The female now joins inwith her own song.
345 00:32:50 (HIGH-PITCHED HOOTING)
346 00:32:58 Together, their duetsends a message to other gibbons.
347 00:33:03 (HIGH-PITCHED HOOTING)
348 00:33:10 It's a declarationthat this patch is taken,
349 00:33:13 and the fruiting trees within it.
350 00:33:16 (HIGH-PITCHED HOOTING)
351 00:33:25 (HIGH-PITCHED HOOTING)
352 00:33:30 Their calls spark responsesfrom other pairs,
353 00:33:34 each protecting their own territory.
354 00:33:42 It's a noisy but effectiveearly-morning roll call
355 00:33:46 to establish the order of the forest.
356 00:33:56 While gibbons singover the forest canopy...
357 00:34:01 ...deep within the forest, someanimals use the plants themselves
358 00:34:06 to transmit their messages.
359 00:34:09 It's a world of soundthat we can't hear...
360 00:34:14 ...but is clear to those that can.
361 00:34:24 A male treehopper.
362 00:34:28 Only half an inch long,
363 00:34:30 it lives in an acoustic worldentirely unlike our own.
364 00:34:36 But with a special laser vibrometer,
365 00:34:39 we can now hear these sounds.
366 00:34:42 (DEEP, RESONANT RUMBLING)
367 00:34:51 He shakes his abdomena hundred times a second
368 00:34:54 to produce a low soundthat vibrates through the stem.
369 00:34:59 (DEEP, RESONANT RUMBLING)
370 00:35:02 It's a courtship song that spreadsthrough every part of the plant.
371 00:35:18 A female receives his messagethrough her legs...
372 00:35:22 loud and clear.
373 00:35:27 She's ready to mate,and she answers back.
374 00:35:30 (DEEP, RESONANT RUMBLING)
375 00:35:37 But she could be anywhereon the plant.
376 00:35:43 To find her, he needs to keepthe conversation flowing.
377 00:35:47 (DEEP, RESONANT RUMBLING)
378 00:36:00 Using her sound to navigate,
379 00:36:02 his direction of travel is determined
380 00:36:05 by whether it hitshis front or rear legs first.
381 00:36:16 He must be quick.
382 00:36:18 Her signal may be picked upby other males on the same plant.
383 00:36:28 But this crossroadis proving hard to read.
384 00:36:36 He checks for directions.
385 00:37:06 (DEEP, RESONANT RUMBLING)
386 00:37:09 Now the signal is coming from behind.
387 00:37:13 He's taken a wrong turn.
388 00:37:23 His detour has cost himvaluable time.
389 00:37:33 Found her at last.
390 00:37:37 But he's too late.
391 00:37:39 Another male has beaten him to it.
392 00:37:45 However, there are plenty moretreehoppers in the forest.
393 00:37:57 (RUMBLING)
394 00:38:02 (RUMBLING)
395 00:38:05 (CHIRPING)
396 00:38:08 Most animal callsare encoded in their DNA.
397 00:38:12 But some can enhance their repertoirein other ways.
398 00:38:16 (CHIRPS AND SINGS)
399 00:38:34 A starling.
400 00:38:36 Ah! Ooh, and a hungry one at that.
401 00:38:39 They are, in fact, one ofour most accomplished singers.
402 00:38:44 And they not only havetheir own songs,
403 00:38:47 but they can also mimicthe songs of other species.
404 00:38:52 And it's all donein order to impress the females.
405 00:38:56 And they're not the only birdthat can imitate others.
406 00:39:05 The forests of Eastern Australia...
407 00:39:07 are home to one of nature'smost accomplished mimics...
408 00:39:14 (CHIRPS)
409 00:39:22 (MIMICS MECHANICAL SOUND)
410 00:39:26 (CHIRPS)
411 00:39:29 (CHIRPS)
412 00:39:35 ...the superb lyrebird.
413 00:39:43 And this mound of earth is his stage.
414 00:39:48 (MIMICS MECHANICAL SOUND)
415 00:39:50 (CHIRPS)
416 00:39:54 (CHIRPS)
417 00:39:56 This modest performancewon't be enough.
418 00:40:00 Female lyrebirds are fussyand demand more complex songs.
419 00:40:08 But he has a solution.
420 00:40:10 He listens carefullyto the sounds around him...
421 00:40:14 (MIMICS ANIMAL HOOTING)
422 00:40:17 (MIMICS HOOTING AND HOLLERING)
423 00:40:22 (CONTINUES HOOTING)
424 00:40:28 ...and mimics them perfectly.
425 00:40:30 (HIGH-PITCHED SINGING)
426 00:40:33 (IMITATES BIRD SONG)
427 00:40:43 (CHIRPS)
428 00:40:45 (IMITATES CHIRPING)
429 00:40:51 He can learn the songsof over 20 different birds.
430 00:40:56 (SINGS)
431 00:40:59 And he's not only a mimic -
432 00:41:02 by stringing the songs togetherin his own way,
433 00:41:05 he's also a composer.
434 00:41:09 (WHISTLES, CHIRPS)
435 00:41:22 (MIMICS MECHANICAL SOUND)
436 00:41:26 No two lyrebirdssing exactly the same tune.
437 00:41:30 (CHIRPS, HOOTS)
438 00:41:34 With age,his songs become more intricate
439 00:41:37 and give him greater successwith the females.
440 00:41:40 (HOOTS, CHIRPS, SINGS)
441 00:41:48 But the lyrebird's worldis changing,
442 00:41:51 and urban settlements have replacedmuch of its natural home.
443 00:41:58 (HORNS HONK)
444 00:42:00 And with it have gonemany of the songsters
445 00:42:03 that he relied on for his tunes.
446 00:42:08 Luckily, this bird is a virtuoso.
447 00:42:13 (ALARM WAILS)
448 00:42:17 A car alarm...
449 00:42:21 (IMITATES ALARM)
450 00:42:24 (IMITATES CAMERA SHUTTER CLICKING)
451 00:42:27 ...a camera shutter...
452 00:42:31 (BABY CRIES)
453 00:42:33 ...and even a crying human baby.
454 00:42:36 (IMITATES BABY CRYING)
455 00:42:41 (WAILS)
456 00:42:45 This sound... is anyone's guess.
457 00:42:54 But it's done the trickand got him noticed...
458 00:42:59 ...a female.
459 00:43:01 He may havean unusual choice of tunes,
460 00:43:04 but they add to his repertoire,and that's all matters.
461 00:43:08 (CHIRPS)
462 00:43:11 If she is impressed,she'll choose him to father
463 00:43:15 the next generationof master songsters and mimics.
464 00:43:19 (HOOTS, CHIRPS)
465 00:43:27 (HONKING, CHIRPING)
466 00:43:30 (ANIMALS CALL AND HOOT)
467 00:43:37 Many of the sounds we hear in natureare the voices of animals.
468 00:43:44 But some creatures are so quiet,
469 00:43:46 they appear to be makingno sound at all.
470 00:43:51 We wanted to film one of these -the treehopper.
471 00:43:55 But how do you recordthe sound of a creature
472 00:43:58 we ourselves can't even hear?
473 00:44:02 Dr Rex Cocroft is a biologistat the University of Missouri.
474 00:44:09 He's fascinated by creatures thatcommunicate using just vibrations.
475 00:44:18 There are at least200,000 species out there
476 00:44:22 singing in waysthat are silent to us.
477 00:44:25 And that's way more songs thanif you add up all of the birds,
478 00:44:29 and the fish and the whales,and the frogs out there. So...
479 00:44:32 the majority of animal sounds areones that we don't actually hear.
480 00:44:38 Which makes thema challenge to study.
481 00:44:44 But a special sound-recording devicesolved the problem.
482 00:44:51 It's called a vibrometer...
483 00:44:54 and uses a laser beam to detectthe slightest vibrations
484 00:44:57 on the surface of an object.
485 00:45:01 By amplifying these sounds,
486 00:45:03 the vibrometer allowed Rex to listenin on treehopper communication.
487 00:45:10 (TREEHOPPER CHIRPING AND TAPPING)
488 00:45:14 This little treehoppersounds like a tap-dancing monkey.
489 00:45:20 (RHYTHMIC HOOTING)
490 00:45:23 Another one sounded likean owl laughing at its own joke.
491 00:45:27 (RHYTHMIC HOOTING)
492 00:45:29 (CLUCKING)
493 00:45:34 One male treehoppersounded like a clucking hen.
494 00:45:39 (CLUCKS)
495 00:45:41 (TREEHOPPER RATTLING)
496 00:45:44 Another onesounded like a woodpecker...
497 00:45:47 followed by a tiny car honking.
498 00:45:49 (HONKS AND RATTLES)
499 00:45:53 Oh, my gosh.I was just lost at that moment.
500 00:45:57 There was no going back becauseI heard these wonderful... sounds
501 00:46:02 that were right therein one small plant.
502 00:46:07 Let me put this here.And how high do you want this?
503 00:46:10 Rex's discovery proved irresistibleto our film crew,
504 00:46:14 led by Director Nalini Crack.
505 00:46:19 Nalini wants to recordthe courtship duet of a treehopper.
506 00:46:28 Helping her is Vikrant Palanfrom Polytec,
507 00:46:31 with his company'smost advanced vibrometer.
508 00:46:34 Yeah.
509 00:46:36 Getting there. Yeah.Good, good, good. Good, good.
510 00:46:39 Nalini has placed a femaleon the stem of the plant.
511 00:46:43 Let's try putting a male on there
512 00:46:46 and see if we can get him calling.
513 00:46:52 The male songwill vibrate through the stem.
514 00:46:56 If the female answers,he'll follow her call.
515 00:47:02 Go on, little guy.
516 00:47:07 (DEEP, RESONANT RUMBLING)
517 00:47:09 (GASPS)Here he goes.
518 00:47:11 That was him.Yeah.
519 00:47:14 (DEEP, RESONANT RUMBLING)- Wow!
520 00:47:21 But his vibrationsaren't having the desired effect.
521 00:47:26 She doesn't want him. (LAUGHS)
522 00:47:28 She's not into it.
523 00:47:32 (DEEP, RESONANT RUMBLING)
524 00:47:37 (FEMALE TREEHOPPER RUMBLES)Oh, wow.
525 00:47:39 Finally, his love song is answered.
526 00:47:42 (LAUGHS) It's amazing.
527 00:47:59 These insects that sing silently
528 00:48:01 are just as magical in their way.
529 00:48:06 We're only justbeginning to understand
530 00:48:09 the secret soundsof nature's smallest creatures.
531 00:48:27 The story of sound continues...
532 00:48:30 (CHIRPING)
533 00:48:32 ...as baby animals attempt to survive
534 00:48:36 in a perilous world...
535 00:48:38 with the help of their voices.(CHIRPS)(YELPS)
536 00:48:41 (HOWLING)
537 00:48:47 (WHISTLING, CHIRPING)
538 00:48:50 AccessibleCustomerService@sky.uk