Why do whales sing? - Stephanie Sardelis
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0:08 - 0:11Communicating underwater is challenging.
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0:11 - 0:17Light and odors don't travel well,
so it's hard for animals to see or smell. -
0:17 - 0:22But sound moves about four times
faster in water than in air, -
0:22 - 0:23so in this dark environment,
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0:23 - 0:28marine mammals often rely
on vocalization to communicate. -
0:28 - 0:32That's why a chorus of sounds fills
the ocean. -
0:32 - 0:33Clicks,
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0:33 - 0:34pulses,
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0:34 - 0:35whistles,
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0:35 - 0:35groans,
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0:35 - 0:36boings,
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0:36 - 0:37cries,
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0:37 - 0:40and trills, to name a few.
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0:40 - 0:42But the most famous parts of this
underwater symphony -
0:42 - 0:48are the evocative melodies, or songs,
composed by the world's largest mammals, -
0:48 - 0:51whales.
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0:51 - 0:55Whale songs are one of the most
sophisticated communication systems -
0:55 - 0:56in the animal kingdom.
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0:56 - 0:59Only a few species are known to sing.
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0:59 - 1:00Blue,
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1:00 - 1:01fin,
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1:01 - 1:02bowhead
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1:02 - 1:03minke whales,
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1:03 - 1:06and of course humpback whales.
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1:06 - 1:08These are all baleen whales
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1:08 - 1:13which use hairy baleen plates
instead of teeth to trap their prey. -
1:13 - 1:16Meanwhile, toothed whales do use
echolocation, -
1:16 - 1:19and they and other species
of baleen whales -
1:19 - 1:24make social sounds, such as
cries and whistles, to communicate. -
1:24 - 1:28But those vocalizations
lack the complexity of songs. -
1:28 - 1:30So how do they do it?
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1:30 - 1:35Land mammals like us generate sound
by moving air over our vocal cords -
1:35 - 1:38when we exhale,
causing them to vibrate. -
1:38 - 1:42Baleen whales have a U-shaped fold
of tissue between their lungs -
1:42 - 1:47and their large inflatable organs
called laryngeal sacs. -
1:47 - 1:50We don't know this for sure
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1:50 - 1:53because it's essentially impossible
to observe the internal organs -
1:53 - 1:55of a living, singing whale,
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1:55 - 1:57but we think that when a whale sings,
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1:57 - 2:00muscular contractions in the throat
and chest -
2:00 - 2:06move air from the lungs across
the U-fold and into the laryngeal sacs, -
2:06 - 2:08causing the U-fold to vibrate.
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2:08 - 2:14The resulting sound resonates in the sacs
like a choir singing in a cathedral -
2:14 - 2:19making songs loud enough to propagate
up to thousands of kilometers away. -
2:19 - 2:22Whales don't have to exhale to sing.
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2:22 - 2:25Instead, the air is recycled
back into the lungs, -
2:25 - 2:28creating sound once more.
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2:28 - 2:32One reason whale songs are so fascinating
is their pattern. -
2:32 - 2:37Units, like moans, cries, and chirps
are arranged in phrases. -
2:37 - 2:40Repeated phrases
are assembled into themes. -
2:40 - 2:45Multiple themes repeated in a predictable
pattern create a song. -
2:45 - 2:47This hierarchical structure
is a kind of grammar. -
2:47 - 2:51Whale songs are extremely variable
in duration, -
2:51 - 2:54and whales can repeat them over and over.
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2:54 - 3:00In one recorded session,
a humpback whale sang for 22 hours. -
3:00 - 3:02And why do they do it?
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3:02 - 3:05We don't yet know the exact purpose,
but we can speculate. -
3:05 - 3:09Given that the singers are males and
they mostly sing during the mating season, -
3:09 - 3:12songs might be used to attract females.
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3:12 - 3:17Or perhaps they're territorial,
used to deter other males. -
3:17 - 3:21Whales return to the same feeding
and breeding grounds annually, -
3:21 - 3:25and each discrete population has
a different song. -
3:25 - 3:31Songs evolve over time as units
or phrases are added, changed, or dropped. -
3:31 - 3:35And when males from different populations
are feeding within earshot, -
3:35 - 3:37phrases are often exchanged,
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3:37 - 3:42maybe because new songs make them more
attractive to breeding females. -
3:42 - 3:46This is one of the fastest examples
of cultural transmission, -
3:46 - 3:49where learned behaviors are passed
between unrelated individuals -
3:49 - 3:52of the same species.
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3:52 - 3:55We can eavesdrop on these songs
using underwater microphones -
3:55 - 3:56called hydrophones.
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3:56 - 4:02These help us track species when sightings
or genetic samples are rare. -
4:02 - 4:05For example, scientists have been able
to differentiate -
4:05 - 4:10the elusive blue whale's populations
worldwide based on their songs. -
4:10 - 4:15But the oceans are getting noisier
as a result of human activity. -
4:15 - 4:16Boating,
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4:16 - 4:17military sonar,
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4:17 - 4:18underwater construction,
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4:18 - 4:22and seismic surveys for oil
are occurring more often -
4:22 - 4:25which may interfere
with whale's communication. -
4:25 - 4:29Some whales will avoid key feeding
or breeding grounds -
4:29 - 4:31if human noise is too loud.
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4:31 - 4:35And humpback whales have been observed
to reduce their singing -
4:35 - 4:39in response to noise 200 kilometers away.
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4:39 - 4:42Limiting human activity
along migratory routes -
4:42 - 4:44and in other critical habitats,
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4:44 - 4:46and reducing noise pollution
throughout the ocean -
4:46 - 4:50would help ensure
whales continued survival. -
4:50 - 4:53If the whales can keep singing
and we can keep listening, -
4:53 - 4:57maybe one day we'll truly understand
what they're saying.
- Title:
- Why do whales sing? - Stephanie Sardelis
- Speaker:
- Stephanie Sardelis
- Description:
-
View full lesson: http://ed.ted.com/lessons/how-do-whales-sing-stephanie-sardelis
Communicating underwater is challenging. Light and odors don’t travel well, but sound moves about four times faster in water than in air — which means marine mammals often use sounds to communicate. The most famous of these underwater vocalizations is undoubtedly the whale song. Stephanie Sardelis decodes the evocative melodies composed by the world’s largest mammals.
Lesson by Stephanie Sardelis, animation by Boniato Studio.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 05:13
Michelle Mehrtens edited English subtitles for Why do whales sing? - Stephanie Sardelis | ||
Camille Martínez commented on English subtitles for Why do whales sing? - Stephanie Sardelis | ||
Camille Martínez edited English subtitles for Why do whales sing? - Stephanie Sardelis | ||
Jessica Ruby edited English subtitles for Why do whales sing? - Stephanie Sardelis | ||
Jessica Ruby edited English subtitles for Why do whales sing? - Stephanie Sardelis | ||
Jessica Ruby approved English subtitles for Why do whales sing? - Stephanie Sardelis | ||
Jessica Ruby accepted English subtitles for Why do whales sing? - Stephanie Sardelis | ||
Jessica Ruby edited English subtitles for Why do whales sing? - Stephanie Sardelis |
Camille Martínez
At 1:30, "vocal chords" was updated to read, "vocal cords." 12.15.16