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  • Well, now we're going to the Bahamas to meet

  • a remarkable group of dolphins that I've been working with

  • in the wild for the last 28 years.

  • Now I'm interested in dolphins because of their large brains

  • and what they might be doing with all that brainpower

  • in the wild.

  • And we know they use some of that brainpower

  • for just living complicated lives,

  • but what do we really know about dolphin intelligence?

  • Well, we know a few things.

  • We know that their brain-to-body ratio,

  • which is a physical measure of intelligence,

  • is second only to humans.

  • Cognitively, they can understand

  • artificially-created languages.

  • And they pass self-awareness tests in mirrors.

  • And in some parts of the world, they use tools,

  • like sponges to hunt fish.

  • But there's one big question left:

  • do they have a language, and if so,

  • what are they talking about?

  • So decades ago, not years ago,

  • I set out to find a place in the world

  • where I could observe dolphins underwater

  • to try to crack the code of their communication system.

  • Now in most parts of the world, the water's pretty murky,

  • so it's very hard to observe animals underwater,

  • but I found a community of dolphins that live

  • in these beautiful, clear, shallow sandbanks of the Bahamas

  • which are just east of Florida.

  • And they spend their daytime resting and socializing

  • in the safety of the shallows, but at night,

  • they go off the edge and hunt in deep water.

  • Now, it's not a bad place to be a researcher, either.

  • So we go out for about five months every summer

  • in a 20-meter catamaran, and we live, sleep and work

  • at sea for weeks at a time.

  • My main tool is an underwater video with a hydrophone,

  • which is an underwater microphone, and this is so

  • I can correlate sound and behavior.

  • And most of our work's pretty non-invasive.

  • We try to follow dolphin etiquette while we're in the water,

  • since we're actually observing them physically in the water.

  • Now, Atlantic spotted dolphins are a really nice species

  • to work with for a couple of reasons.

  • They're born without spots, and they get spots with age,

  • and they go through pretty distinct developmental phases,

  • so that's fun to track their behavior.

  • And by about the age of 15, they're fully spotted black and white.

  • Now the mother you see here is Mugsy.

  • She's 35 years old in this shot,

  • but dolphins can actually live into their early 50s.

  • And like all the dolphins in our community,

  • we photographed Mugsy and tracked her little spots

  • and nicks in her dorsal fin,

  • and also the unique spot patterns

  • as she matured over time.

  • Now, young dolphins learn a lot as they're growing up,

  • and they use their teenage years to practice social skills,

  • and at about the age of nine, the females

  • become sexually mature, so they can get pregnant,

  • and the males mature quite a bit later,

  • at around 15 years of age.

  • And dolphins are very promiscuous,

  • and so we have to determine who the fathers are,

  • so we do paternity tests by collecting fecal material

  • out of the water and extracting DNA.

  • So what that means is, after 28 years,

  • we are tracking three generations,

  • including grandmothers and grandfathers.

  • Now, dolphins are natural acousticians.

  • They make sounds 10 times as high

  • and hear sounds 10 times as high as we do.

  • But they have other communication signals they use.

  • They have good vision, so they use body postures to communicate.

  • They have taste, not smell.

  • And they have touch.

  • And sound can actually be felt in the water,

  • because the acoustic impedance of tissue and water's about the same.

  • So dolphins can buzz and tickle each other at a distance.

  • Now, we do know some things about how sounds are used

  • with certain behaviors.

  • Now, the signature whistle is a whistle

  • that's specific to an individual dolphin, and it's like a name. (Dolphin whistling noises)

  • And this is the best-studied sound,

  • because it's easy to measure, really,

  • and you'd find this whistle when mothers and calves

  • are reuniting, for example.

  • Another well studied sound are echolocation clicks.

  • This is the dolphin's sonar. (Dolphin echolocation noises)

  • And they use these clicks to hunt and feed.

  • But they can also tightly pack these clicks together

  • into buzzes and use them socially.

  • For example, males will stimulate a female

  • during a courtship chase.

  • You know, I've been buzzed in the water.

  • (Laughter)

  • Don't tell anyone. It's a secret.

  • And you can really feel the sound. That was my point with that.

  • (Laughter)

  • So dolphins are also political animals,

  • so they have to resolve conflicts.

  • (Dolphin noises)

  • And they use these burst-pulsed sounds as well as

  • their head-to-head behaviors when they're fighting.

  • And these are very unstudied sounds

  • because they're hard to measure.

  • Now this is some video of a typical dolphin fight.

  • (Dolphin noises)

  • So you're going to see two groups,

  • and you're going to see the head-to-head posturing,

  • some open mouths,

  • lots of squawking.

  • There's a bubble.

  • And basically, one of these groups will kind of back off

  • and everything will resolve fine,

  • and it doesn't really escalate into violence too much.

  • Now, in the Bahamas, we also have resident bottlenose

  • that interact socially with the spotted dolphins.

  • For example, they babysit each other's calves.

  • The males have dominance displays that they use

  • when they're chasing each other's females.

  • And the two species actually form temporary alliances

  • when they're chasing sharks away.

  • And one of the mechanisms they use to communicate

  • their coordination is synchrony.

  • They synchronize their sounds and their body postures

  • to look bigger and sound stronger.

  • (Dolphins noises)

  • Now, these are bottlenose dolphins,

  • and you'll see them starting to synchronize

  • their behavior and their sounds.

  • (Dolphin noises)

  • You see, they're synchronizing with their partner

  • as well as the other dyad.

  • I wish I was that coordinated.

  • Now, it's important to remember that you're only hearing

  • the human-audible parts of dolphin sounds,

  • and dolphins make ultrasonic sounds,

  • and we use special equipment in the water

  • to collect these sounds.

  • Now, researchers have actually measured whistle complexity

  • using information theory,

  • and whistles rate very high relative to even human languages.

  • But burst-pulsed sounds is a bit of a mystery.

  • Now, these are three spectragrams.

  • Two are human words, and one is a dolphin vocalizing.

  • So just take a guess in your mind which one is the dolphin.

  • Now, it turns out burst-pulsed sounds actually look

  • a bit like human phonemes.

  • Now, one way to crack the code

  • is to interpret these signals and figure out what they mean,

  • but it's a difficult job, and we actually don't have a Rosetta Stone yet.

  • But a second way to crack the code

  • is to develop some technology,

  • an interface to do two-way communication,

  • and that's what we've been trying to do in the Bahamas

  • and in real time.

  • Now, scientists have used keyboard interfaces

  • to try to bridge the gap with species

  • including chimpanzees and dolphins.

  • This underwater keyboard in Orlando, Florida,

  • at the Epcot Center, was actually

  • the most sophisticated ever two-way interface designed

  • for humans and dolphins to work together under the water

  • and exchange information.

  • So we wanted to develop an interface like this

  • in the Bahamas, but in a more natural setting.

  • And one of the reasons we thought we could do this

  • is because the dolphins were starting to show us

  • a lot of mutual curiosity.

  • They were spontaneously mimicking our vocalizations

  • and our postures, and they were also inviting us

  • into dolphin games.

  • Now, dolphins are social mammals, so they love to play,

  • and one of their favorite games is to drag seaweed,

  • or sargassum in this case, around.

  • And they're very adept. They like to drag it

  • and drop it from appendage to appendage.

  • Now in this footage, the adult is Caroh.

  • She's 25 years old here, and this is her newborn, Cobalt,

  • and he's just learning how to play this game.

  • (Dolphin noises)

  • She's kind of teasing him and taunting him.

  • He really wants that sargassum.

  • Now, when dolphins solicit humans for this game,

  • they'll often sink vertically in the water,

  • and they'll have a little sargassum on their flipper,

  • and they'll sort of nudge it and drop it sometimes

  • on the bottom and let us go get it,

  • and then we'll have a little seaweed keep away game.

  • But when we don't dive down and get it,

  • they'll bring it to the surface

  • and they'll sort of wave it in front of us on their tail

  • and drop it for us like they do their calves,

  • and then we'll pick it up and have a game.

  • And so we started thinking, well, wouldn't it be neat

  • to build some technology that would allow the dolphins

  • to request these things in real time, their favorite toys?

  • So the original vision was to have a keyboard

  • hanging from the boat attached to a computer,

  • and the divers and dolphins would activate the keys

  • on the keypad and happily exchange information

  • and request toys from each other.

  • But we quickly found out that dolphins simply

  • were not going to hang around the boat using a keyboard.

  • They've got better things to do in the wild.

  • They might do it in captivity, but in the wild --

  • So we built a portable keyboard that we could push through the water,

  • and we labeled four objects they like to play with,

  • the scarf, rope, sargassum, and also had a bow ride,

  • which is a fun activity for a dolphin. (Whistle)

  • And that's the scarf whistle,

  • which is also associated with a visual symbol.

  • And these are artificially created whistles.

  • They're outside the dolphin's normal repertoire,

  • but they're easily mimicked by the dolphins.

  • And I spent four years with my colleagues Adam Pack and Fabienne Delfour,

  • working out in the field with this keyboard

  • using it with each other to do requests for toys

  • while the dolphins were watching.

  • And the dolphins could get in on the game.

  • They could point at the visual object,

  • or they could mimic the whistle.

  • Now this is video of a session.

  • The diver here has a rope toy,

  • and I'm on the keyboard on the left,

  • and I've just played the rope key,

  • and that's the request for the toy from the human.

  • So I've got the rope, I'm diving down,

  • and I'm basically trying to get the dolphin's attention,

  • because they're kind of like little kids.

  • You have to keep their attention.

  • I'm going to drop the rope, see if they come over.

  • Here they come,

  • and then they're going to pick up the rope

  • and drag it around as a toy.

  • Now, I'm at the keyboard on the left,

  • and this is actually the first time that we tried this.

  • I'm going to try to request this toy, the rope toy,

  • from the dolphins using the rope sound.

  • Let's see if they might actually understand what that means.

  • (Whistle)

  • That's the rope whistle.

  • Up come the dolphins,

  • and drop off the rope, yay. Wow.

  • (Applause)