Name: 【TED】Peter Tyack: The intriguing sound of marine mammals (Peter Tyack: The intriguing sound of marine mammals)
Uploaded: 2017-02-24T15:50:32.000Z
Duration: 22 min 37 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Thank you so much. I'm going to try to take you

on a journey of the underwater acoustic world

it's hard for us to really understand this,

so I'll use a mixture of figures and sounds

But let's also think, as a visual species,

what it's like when we go snorkeling or diving

all of a sudden is very restricted and claustrophobic.

and also to stay in touch with one another.

Dolphins and toothed whales use echolocation.

and listen for echoes from the sea floor in order to orient.

and to decide which one they want to eat.

All marine mammals use sound for communication to stay in touch.

which are used in reproductive advertisement

for male and females, both to find one another

And mother and young and closely bonded animals

use calls to stay in touch with one another,

so sound is really critical for their lives.

The first thing that got me interested in the sounds

that captive dolphins could imitate human sounds.

This is a plot of frequency against time --

where the higher notes are up higher and the lower notes are lower,

This is a picture of a trainer's whistle,

a whistle a trainer will blow to tell a dolphin

it's done the right thing and can come get a fish.

It sounds sort of like "tweeeeeet." Like that.

If you hummed this tune to your dog or cat

It's really important for our music and our language.

So it's a puzzle: The few other mammal groups that do this,

So let's start with calls of a nonhuman primate.

Many mammals have to produce contact calls

This is an example of a call produced by squirrel monkeys

each individual here has a radically different call.

in order to develop more complicated and more distinctive calls

How about the setting in which animals need to use this call?

In normal life for mother and calf dolphin,

they'll often drift apart or swim apart if Mom is chasing a fish,

What this figure shows is the percentage of the separations

So when dolphins are separating by less than 20 meters,

less than half the time they need to use whistles.

Most of the time they can just find each other

But all of the time when they separate by more than 100 meters,

they need to use these individually distinctive whistles

Most of these distinctive signature whistles

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【TED】Peter Tyack: The intriguing sound of marine mammals (Peter Tyack: The intriguing sound of marine mammals)

potential

imitate

critical

average