1
00:00:13,480 --> 00:00:16,382
NARRATOR: They're some
of the most dynamic,
2
00:00:16,384 --> 00:00:21,954
dazzling, jaw-dropping displays
in nature.
3
00:00:24,491 --> 00:00:28,761
EDIE WIDDER: It's these rocket
ships and explosions of sparks
4
00:00:28,763 --> 00:00:31,296
and spewing of what looks like
blue smoke.
5
00:00:33,633 --> 00:00:37,002
And these long chains
that look like Japanese lanterns
6
00:00:37,004 --> 00:00:40,739
extending off into the distance
as far as you can see.
7
00:00:40,741 --> 00:00:42,374
It's magic!
8
00:00:42,376 --> 00:00:44,643
NARRATOR:
Some flash.
9
00:00:46,246 --> 00:00:49,181
Some sparkle.
10
00:00:50,917 --> 00:00:53,285
Others simply glow.
11
00:00:56,556 --> 00:01:00,826
But most we're only beginning
to discover.
12
00:01:00,828 --> 00:01:02,027
Suddenly we recognize it,
13
00:01:02,029 --> 00:01:03,829
and now we find it everywhere
under there.
14
00:01:03,831 --> 00:01:06,131
NARRATOR:
Hidden in the deepest, darkest,
15
00:01:06,133 --> 00:01:09,668
most remote stretches
of our planet,
16
00:01:09,670 --> 00:01:12,538
these luminous critters
can be timid performers.
17
00:01:16,309 --> 00:01:19,478
But the closer we look,
the more we realize
18
00:01:19,480 --> 00:01:22,781
the light they create
is pervasive.
19
00:01:22,783 --> 00:01:25,484
JOHN SPARKS: If it wasn't
important to the organisms,
20
00:01:25,486 --> 00:01:27,646
you wouldn't see it
all over the tree of life.
21
00:01:28,621 --> 00:01:32,458
NARRATOR: Now scientists are
thrusting these cryptic creatures
22
00:01:32,460 --> 00:01:35,461
and their fantastical displays
into the limelight.
23
00:01:37,163 --> 00:01:40,065
Some are even attempting
to harness this light,
24
00:01:40,067 --> 00:01:42,668
co-opting millions of years
of evolution
25
00:01:42,670 --> 00:01:47,072
for the betterment
of our own dim species.
26
00:01:47,074 --> 00:01:48,907
DAVID GRUBER:
We have to go down to the ocean
27
00:01:48,909 --> 00:01:51,977
to find these animals
that give off light
28
00:01:51,979 --> 00:01:54,713
so we can then understand
ourselves.
29
00:01:54,715 --> 00:01:57,549
To me, it's a beautiful
connection.
30
00:02:00,220 --> 00:02:04,623
NARRATOR: We're shedding light
on the "Creatures of Light,"
31
00:02:04,625 --> 00:02:08,127
right now on this NOVA/
National Geographi special.
32
00:02:29,449 --> 00:02:33,889
Major funding for NOVA is provided by the following::
It's one of life's essential ingredients.
33
00:02:34,087 --> 00:02:36,455
We soak up its energy.
34
00:02:37,891 --> 00:02:39,758
Set our clocks by it.
35
00:02:40,827 --> 00:02:43,529
Need it to see.
36
00:02:44,998 --> 00:02:48,534
Light is so precious
to us humans,
37
00:02:48,536 --> 00:02:51,470
we've coaxed it into lasting
all night long.
38
00:02:54,807 --> 00:02:56,742
But imagine a world without it.
39
00:03:01,548 --> 00:03:02,681
(blows)
40
00:03:08,922 --> 00:03:11,723
While we're cursing
the darkness,
41
00:03:11,725 --> 00:03:14,459
countless thousands
of other species
42
00:03:14,461 --> 00:03:19,198
have evolved
a much brighter response
43
00:03:19,200 --> 00:03:24,136
without burning an ounce
of fossil fuel.
44
00:03:28,007 --> 00:03:30,676
It's called "bioluminescence."
45
00:03:33,012 --> 00:03:34,613
Living light.
46
00:03:42,055 --> 00:03:47,292
And from glowworms and fireflies
to plankton and jellyfish,
47
00:03:47,294 --> 00:03:49,561
it's been lighting up the dark
48
00:03:49,563 --> 00:03:51,483
for hundreds of millions
of years.
49
00:03:53,132 --> 00:03:55,434
JOHN SPARKS: If you look across
the tree of life, essentially,
50
00:03:55,436 --> 00:03:57,516
bioluminescence
is splattered all over it.
51
00:04:00,206 --> 00:04:02,908
EDIE WIDDER:
It's just everywhere you look.
52
00:04:02,910 --> 00:04:04,443
How to survive in the dark?
53
00:04:04,445 --> 00:04:05,410
Make light.
54
00:04:08,648 --> 00:04:12,784
NARRATOR: On land, where
it's dark only at night,
55
00:04:12,786 --> 00:04:15,954
just a fraction of creatures
evolved the gift of glow.
56
00:04:23,796 --> 00:04:27,399
But descend into the deepest
depths of the oceans
57
00:04:27,401 --> 00:04:30,168
where the bulk
of earth's creatures reside,
58
00:04:30,170 --> 00:04:33,805
and you find
a very different story.
59
00:04:33,807 --> 00:04:40,145
Down here, as many as 90%
of life-forms shine.
60
00:04:45,251 --> 00:04:50,022
MAN: I'm going to come off the
wall and head out into open water.
61
00:04:50,024 --> 00:04:52,457
MAN:
Surface, surface, this is Nadir.
62
00:04:52,459 --> 00:04:56,161
Our present depth
is approaching 100 meters.
63
00:04:56,163 --> 00:04:58,397
Life support okay.
64
00:04:59,966 --> 00:05:01,667
NARRATOR:
That's why a team of scientists
65
00:05:01,669 --> 00:05:05,637
from New York's American Museum
of Natural History is here,
66
00:05:05,639 --> 00:05:08,440
plying the dark waters
of the South Pacific Ocean
67
00:05:08,442 --> 00:05:11,610
in search of new
luminescing creatures.
68
00:05:11,612 --> 00:05:15,180
MAN: I'm going to start
motoring away here.
69
00:05:17,283 --> 00:05:20,052
NARRATOR: They've journeyed to
the other side of the world
70
00:05:20,054 --> 00:05:24,990
to the pristine and remote
waters of the Solomon Islands
71
00:05:24,992 --> 00:05:29,995
to unravel how and why
light-producing animals evolved,
72
00:05:29,997 --> 00:05:34,866
and perhaps put their living
light to work for us.
73
00:05:36,636 --> 00:05:39,438
David Gruber
is a marine biologist.
74
00:05:39,440 --> 00:05:43,275
GRUBER: After about 100
meters in the ocean,
75
00:05:43,277 --> 00:05:44,943
you get into this twilight zone.
76
00:05:44,945 --> 00:05:47,245
About one percent of the light
makes it down.
77
00:05:47,247 --> 00:05:49,247
So as we start getting deeper,
78
00:05:49,249 --> 00:05:51,717
you'll start seeing
almost everybody down here.
79
00:05:51,719 --> 00:05:53,819
Every fish that we see
has this ability
80
00:05:53,821 --> 00:05:55,620
to blink or flash
or communicate,
81
00:05:55,622 --> 00:05:58,123
producing its own light.
82
00:06:00,293 --> 00:06:01,660
NARRATOR:
The problem is,
83
00:06:01,662 --> 00:06:04,463
common as bioluminescence
may be down here,
84
00:06:04,465 --> 00:06:08,066
it's challenging to study,
even with a submersible.
85
00:06:12,638 --> 00:06:18,377
The water is too dark,
the distances are too great,
86
00:06:18,379 --> 00:06:20,879
and the light
the animals give off
87
00:06:20,881 --> 00:06:23,548
is too unpredictable.
88
00:06:25,852 --> 00:06:27,052
It's a tough environment
89
00:06:27,054 --> 00:06:29,454
for marine biologists
to work in.
90
00:06:29,456 --> 00:06:32,424
But a neuroscientist
like Vincent Pieribone
91
00:06:32,426 --> 00:06:35,494
feels especially
out of his depth.
92
00:06:35,496 --> 00:06:38,630
PIERIBONE: I'm a scientist that spends
most of his time in a laboratory.
93
00:06:38,632 --> 00:06:40,732
So it's very scary, to be
completely honest with you.
94
00:06:40,734 --> 00:06:42,434
You've got to keep your head
and your wits about you
95
00:06:42,436 --> 00:06:44,002
and try to focus
on what the job is
96
00:06:44,004 --> 00:06:45,570
and not really think
about the fact
97
00:06:45,572 --> 00:06:47,439
that there's, you know,
a few tons of water
98
00:06:47,441 --> 00:06:48,940
on top of us at the moment.
99
00:06:48,942 --> 00:06:52,411
But we're here in the name
of science, so we press on.
100
00:06:52,413 --> 00:06:53,345
(laughs)
101
00:06:57,016 --> 00:06:58,383
Ooh!
102
00:06:58,385 --> 00:07:00,452
That's a photophore.
103
00:07:03,322 --> 00:07:04,956
NARRATOR:
One goal for this trip
104
00:07:04,958 --> 00:07:07,592
is to develop
a better low-light camera.
105
00:07:08,895 --> 00:07:12,364
Deep-sea bioluminescence
has only been filmed in the wild
106
00:07:12,366 --> 00:07:14,166
a handful of times.
107
00:07:16,536 --> 00:07:20,238
Most of what we know
comes from observing animals
108
00:07:20,240 --> 00:07:22,941
in carefully lit tanks
on the surface.
109
00:07:24,911 --> 00:07:26,845
(splashing)
110
00:07:29,582 --> 00:07:31,983
Whether it's the infamous
anglerfish
111
00:07:31,985 --> 00:07:34,920
with its luminous lure
112
00:07:34,922 --> 00:07:37,789
or the light-packed viperfish,
one of the deep's
113
00:07:37,791 --> 00:07:40,392
most ferocious predators,
114
00:07:40,394 --> 00:07:42,527
scientists typically
collect them
115
00:07:42,529 --> 00:07:45,730
in small trawl nets like these.
116
00:07:47,767 --> 00:07:49,301
Bob, you're gonna turn
around the net, right?
117
00:07:49,303 --> 00:07:50,836
Yeah!
All right, thanks.
118
00:07:50,838 --> 00:07:52,704
NARRATOR:
They then examine
119
00:07:52,706 --> 00:07:54,773
their unique
light-producing organs
120
00:07:54,775 --> 00:07:58,510
to infer how they work.
121
00:07:58,512 --> 00:08:01,346
That's what biologist
John Sparks is trying to do
122
00:08:01,348 --> 00:08:04,249
with this viperfish.
123
00:08:04,251 --> 00:08:06,184
They may be fierce,
124
00:08:06,186 --> 00:08:09,821
but even the big ones
are actually pretty small.
125
00:08:09,823 --> 00:08:12,324
SPARKS: This is a monster
for these things.
126
00:08:12,326 --> 00:08:13,992
There are a bunch
of different species.
127
00:08:13,994 --> 00:08:16,194
They're hard to tell apart.
128
00:08:16,196 --> 00:08:18,196
I've actually never seen one
that big.
129
00:08:22,902 --> 00:08:25,170
We still know so little.
130
00:08:25,172 --> 00:08:27,672
That's what's kind of
frustrating.
131
00:08:27,674 --> 00:08:31,243
You've got to get the organisms
up alive, which is tough.
132
00:08:31,245 --> 00:08:32,777
You've got to be able to image
133
00:08:32,779 --> 00:08:36,481
enough different species
to make it meaningful.
134
00:08:36,483 --> 00:08:38,850
But in terms of us doing
135
00:08:38,852 --> 00:08:40,285
anything scientific with it,
136
00:08:40,287 --> 00:08:42,787
it's very tough because
we've got so little data.
137
00:08:44,290 --> 00:08:45,757
NARRATOR: What scientists
want to understand
138
00:08:45,759 --> 00:08:48,426
is how luminescent features
139
00:08:48,428 --> 00:08:50,996
became so pervasive
in the deep ocean.
140
00:08:50,998 --> 00:08:54,900
And why,
in a world full of predators,
141
00:08:54,902 --> 00:08:56,902
would animals invest
so much energy
142
00:08:56,904 --> 00:09:00,639
into lighting up and standing
out in the first place?
143
00:09:05,578 --> 00:09:08,079
They are questions
marine biologist Edie Widder
144
00:09:08,081 --> 00:09:10,315
has been grappling with
for decades.
145
00:09:12,818 --> 00:09:15,120
An expert on living light,
146
00:09:15,122 --> 00:09:19,891
she was among the first
to study it underwater.
147
00:09:19,893 --> 00:09:23,595
EDIE WIDDER: I wish I could describe
what it's like to be down there,
148
00:09:23,597 --> 00:09:25,263
because I would like people
149
00:09:25,265 --> 00:09:27,345
to be able to appreciate it
the way I have.
150
00:09:29,468 --> 00:09:34,439
It's these rocket ships
and explosions of sparks,
151
00:09:34,441 --> 00:09:37,742
and spewing of what looks like
blue smoke,
152
00:09:37,744 --> 00:09:40,812
and these long chains
of siphonophores
153
00:09:40,814 --> 00:09:42,480
that are like chains
of jellyfish
154
00:09:42,482 --> 00:09:44,282
that look like Japanese lanterns
155
00:09:44,284 --> 00:09:49,054
extending off into the distance
as far as you can see.
156
00:09:49,056 --> 00:09:50,188
It's magic.
157
00:09:55,261 --> 00:09:57,462
NARRATOR:
Edie devised her own methods
158
00:09:57,464 --> 00:10:01,666
to trigger these underwater
light shows.
159
00:10:01,668 --> 00:10:06,504
She mounted a large screen
on the front of her submersible.
160
00:10:06,506 --> 00:10:10,976
When creatures bump into it,
they light up,
161
00:10:10,978 --> 00:10:13,912
and her low-light cameras
record them in the act.
162
00:10:17,984 --> 00:10:21,486
Over the years,
the aptly named Splat Cam
163
00:10:21,488 --> 00:10:23,288
has helped bring to light
164
00:10:23,290 --> 00:10:27,659
some of the most bizarre
creatures in the deep.
165
00:10:29,195 --> 00:10:32,897
Everything from jellyfish
to sea cucumbers.
166
00:10:47,780 --> 00:10:49,280
WIDDER:
The open ocean
167
00:10:49,282 --> 00:10:53,952
is the biggest living space
on our planet by far,
168
00:10:53,954 --> 00:10:56,788
and it's a very unusual
environment.
169
00:10:56,790 --> 00:11:00,258
There's no trees or bushes
to hide behind.
170
00:11:00,260 --> 00:11:02,327
But animals have to play
all the same games
171
00:11:02,329 --> 00:11:06,131
of hide-and-seek
that animals do on land.
172
00:11:06,133 --> 00:11:08,433
And that's where bioluminescence
comes in.
173
00:11:12,438 --> 00:11:15,407
NARRATOR:
In this deep, dark abyss,
174
00:11:15,409 --> 00:11:19,711
light, it seems, is vital,
175
00:11:19,713 --> 00:11:22,313
and creatures have evolved
to wield it
176
00:11:22,315 --> 00:11:25,050
in many different ways
for many different reasons.
177
00:11:30,122 --> 00:11:33,258
Tiny organisms called
dinoflagellates, for example,
178
00:11:33,260 --> 00:11:35,427
alight in unison
179
00:11:35,429 --> 00:11:39,698
whenever the water around them
is disturbed,
180
00:11:39,700 --> 00:11:42,267
taking the shape
of whatever swims through them.
181
00:11:48,541 --> 00:11:50,108
It's a treat for the lucky few
182
00:11:50,110 --> 00:11:52,110
who get to bask
in their soft glow.
183
00:11:58,050 --> 00:12:02,487
But for predators
of these microbes, like shrimp,
184
00:12:02,489 --> 00:12:04,622
it's more like tripping
a motion sensor.
185
00:12:07,493 --> 00:12:09,494
Every time they make a move,
186
00:12:09,496 --> 00:12:12,997
the lights come on
and give away their location.
187
00:12:15,101 --> 00:12:20,105
Predator becomes prey
to a host of other creatures,
188
00:12:20,107 --> 00:12:22,207
like cuttlefish.
189
00:12:30,282 --> 00:12:31,449
But some shrimp are armed
190
00:12:31,451 --> 00:12:33,451
with their own
light-filled defenses.
191
00:12:37,089 --> 00:12:41,126
When threatened, certain species
shoot bright flashes of light
192
00:12:41,128 --> 00:12:45,497
to stun and confuse
their enemies.
193
00:12:45,499 --> 00:12:47,098
WIDDER:
There's a lot of animals
194
00:12:47,100 --> 00:12:50,135
that actually can release
their luminescence that way.
195
00:12:50,137 --> 00:12:52,670
So you can have something
like a shrimp
196
00:12:52,672 --> 00:12:54,973
that will spew luminescence
out of its mouth
197
00:12:54,975 --> 00:12:56,941
like a fire-breathing dragon
198
00:12:56,943 --> 00:12:58,810
and temporarily blind
its predator
199
00:12:58,812 --> 00:13:00,852
while it pulses away
into the darkness.
200
00:13:04,216 --> 00:13:06,785
NARRATOR: Rather than
blinding their predators,
201
00:13:06,787 --> 00:13:10,488
a huge variety of fish,
from squid to sharks,
202
00:13:10,490 --> 00:13:13,158
use light to hide from them.
203
00:13:15,127 --> 00:13:17,729
It's called
counter-illumination,
204
00:13:17,731 --> 00:13:20,799
and it may seem
counterintuitive,
205
00:13:20,801 --> 00:13:23,868
but consider how a fish
swimming near the surface
206
00:13:23,870 --> 00:13:28,006
appears to a predator
in the depths below.
207
00:13:28,008 --> 00:13:30,909
As sunlight or moonlight
beams down on them,
208
00:13:30,911 --> 00:13:34,913
their silhouettes
are plain as day.
209
00:13:36,949 --> 00:13:39,417
WIDDER: And so an enormous
amount of animals in the ocean
210
00:13:39,419 --> 00:13:41,920
produce bioluminescence
from their bellies
211
00:13:41,922 --> 00:13:45,990
that exactly matches
the intensity and the color
212
00:13:45,992 --> 00:13:48,860
of the sunlight coming down
through sea water.
213
00:13:50,529 --> 00:13:54,732
NARRATOR: When the lights
come on, the animals vanish.
214
00:13:57,336 --> 00:13:59,938
WIDDER:
It's an amazing cloaking device.
215
00:13:59,940 --> 00:14:03,241
They just disappear,
utterly disappear.
216
00:14:06,612 --> 00:14:10,715
NARRATOR: Others, like ostracods,
tiny shrimplike critters,
217
00:14:10,717 --> 00:14:14,853
use light
a bit more extravagantly.
218
00:14:14,855 --> 00:14:19,757
They ooze light to stand out
and impress the opposite sex.
219
00:14:22,161 --> 00:14:25,563
WIDDER: Ostracods, which are
about the size of sesame seeds,
220
00:14:25,565 --> 00:14:29,534
produce a crazy amount of light
for such a little organism.
221
00:14:29,536 --> 00:14:32,003
And they'll squirt out
one little dot,
222
00:14:32,005 --> 00:14:33,471
and then they swim
a little further
223
00:14:33,473 --> 00:14:35,707
and they squirt out another dot,
and another dot.
224
00:14:35,709 --> 00:14:39,510
And the spacing of the dots
is species-specific,
225
00:14:39,512 --> 00:14:43,114
and so the female can recognize
the male that she can mate with.
226
00:14:43,116 --> 00:14:47,018
So it's almost like skywriting,
but it's light writing.
227
00:14:47,020 --> 00:14:48,453
It's beautiful.
228
00:14:51,991 --> 00:14:57,195
NARRATOR: But mates aren't the
only creatures light attracts.
229
00:14:57,197 --> 00:15:01,466
Many fish use light
to lure food in,
230
00:15:01,468 --> 00:15:05,536
as does the most notorious
bioluminescent creature of all.
231
00:15:09,108 --> 00:15:11,276
What is that?
232
00:15:11,278 --> 00:15:13,711
It's so pretty.
233
00:15:15,381 --> 00:15:18,416
WIDDER: Remember that ugly
angler in Finding Nemo?
234
00:15:18,418 --> 00:15:19,684
Good feeling's gone.
235
00:15:20,753 --> 00:15:22,320
(screeching)
236
00:15:22,322 --> 00:15:25,556
WIDDER: That lure is actually
meant to attract another fish
237
00:15:25,558 --> 00:15:28,393
or another little shrimp
that comes to gobble it up...
238
00:15:28,395 --> 00:15:29,894
(screaming)
239
00:15:29,896 --> 00:15:30,995
WIDDER: ...and then
finds itself engulfed
240
00:15:30,997 --> 00:15:33,765
in this living mousetrap
of needle-sharp teeth.
241
00:15:36,969 --> 00:15:38,529
NARRATOR:
Lures.
242
00:15:39,872 --> 00:15:42,407
Motion sensors.
243
00:15:42,409 --> 00:15:44,575
Cloaking devices.
244
00:15:46,946 --> 00:15:51,282
All together, bioluminescence
lights up the deep
245
00:15:51,284 --> 00:15:53,217
like an aquatic Times Square.
246
00:15:56,755 --> 00:15:59,123
GRUBER: Bioluminescence was a
tool that was laying out there,
247
00:15:59,125 --> 00:16:01,359
and somebody was like,
"I could use it for this,"
248
00:16:01,361 --> 00:16:02,927
and somebody's like,
"Well, I could use it for that."
249
00:16:02,929 --> 00:16:05,430
SPARKS:
They use it to find food.
250
00:16:05,432 --> 00:16:07,865
They use it to avoid
being eaten.
251
00:16:07,867 --> 00:16:09,968
They use it for mating.
252
00:16:09,970 --> 00:16:11,302
And they use it to communicate
with each other,
253
00:16:11,304 --> 00:16:12,704
just like all these signals
254
00:16:12,706 --> 00:16:14,305
are trying
to communicate with us.
255
00:16:14,307 --> 00:16:17,342
Things that are very important
to not only the individual
256
00:16:17,344 --> 00:16:20,111
but the species as well.
257
00:16:22,047 --> 00:16:24,983
NARRATOR:
Despite all the risks,
258
00:16:24,985 --> 00:16:29,554
light is a shining example
of Darwin's theory of evolution.
259
00:16:31,090 --> 00:16:34,292
From bacteria
to jellies to fish,
260
00:16:34,294 --> 00:16:36,828
it helps organisms survive.
261
00:16:40,833 --> 00:16:44,035
But the question remains:
262
00:16:44,037 --> 00:16:48,406
how did the initial spark
for this light arise?
263
00:16:53,579 --> 00:16:56,114
To find out,
scientists have turned
264
00:16:56,116 --> 00:16:59,984
to a different set
of bioluminescent creatures,
265
00:16:59,986 --> 00:17:03,388
ones that are a bit more
familiar and easier to study.
266
00:17:05,424 --> 00:17:09,761
Land critters have evolved their
own special ways of using light.
267
00:17:11,864 --> 00:17:15,366
Take the glowworm, for example.
268
00:17:15,368 --> 00:17:18,503
Like anglerfish of the deep,
thousands of these fly larvae
269
00:17:18,505 --> 00:17:21,773
light up the roofs
of these caves in New Zealand
270
00:17:21,775 --> 00:17:24,308
like the night sky
to lure in a meal.
271
00:17:27,479 --> 00:17:30,681
The starry ceiling fools prey
like flies and moths,
272
00:17:30,683 --> 00:17:33,651
which are attracted
to the light.
273
00:17:36,555 --> 00:17:39,957
As they fly upwards,
they get trapped
274
00:17:39,959 --> 00:17:43,094
by the glowworms' sticky,
threadlike snares.
275
00:17:50,569 --> 00:17:53,738
Rather than luring prey in,
other bioluminescent creatures,
276
00:17:53,740 --> 00:17:57,041
like this millipede
in the Sierra Nevadas,
277
00:17:57,043 --> 00:18:01,612
uses light as high-voltage signs
to keep predators out.
278
00:18:06,785 --> 00:18:10,555
The bugs are laced with cyanide.
279
00:18:10,557 --> 00:18:13,691
Their nuclear glow
alerts potential predators
280
00:18:13,693 --> 00:18:15,526
to leave them alone.
281
00:18:23,836 --> 00:18:25,770
And then there are probably
282
00:18:25,772 --> 00:18:28,806
the most familiar
displays of all.
283
00:18:32,845 --> 00:18:35,046
The brilliant flashes
of fireflies
284
00:18:35,048 --> 00:18:36,681
are some of the most
sophisticated
285
00:18:36,683 --> 00:18:38,983
mating strategies ever evolved,
286
00:18:38,985 --> 00:18:43,154
the ultimate
in romance languages.
287
00:18:47,860 --> 00:18:51,429
By triggering a chemical
reaction in their abdomens,
288
00:18:51,431 --> 00:18:57,735
male fireflies can turn
themselves on or off on cue.
289
00:18:59,138 --> 00:19:01,139
And if they do it just right,
290
00:19:01,141 --> 00:19:03,708
they'll turn on
female fireflies too.
291
00:19:13,585 --> 00:19:16,888
University of Florida biologist
Marc Branham
292
00:19:16,890 --> 00:19:19,023
has devoted the last 15 years
293
00:19:19,025 --> 00:19:22,260
to deciphering this elaborate
language of love.
294
00:19:24,029 --> 00:19:26,297
BRANHAM:
It's like breaking the code.
295
00:19:27,566 --> 00:19:31,335
NARRATOR: A secret code
that has two parts.
296
00:19:31,337 --> 00:19:32,670
BRANHAM:
If you actually measure
297
00:19:32,672 --> 00:19:36,307
these flash patterns
very, very carefully,
298
00:19:36,309 --> 00:19:40,478
there are some features
that are always standardized,
299
00:19:40,480 --> 00:19:42,947
and we think those are the parts
of the signal
300
00:19:42,949 --> 00:19:45,917
which say, "I'm a member
of the following species."
301
00:19:47,252 --> 00:19:51,489
NARRATOR: One of the 2,000
different species of firefly,
302
00:19:51,491 --> 00:19:54,992
which are actually
not flies at all...
303
00:19:54,994 --> 00:19:57,195
They're beetles.
304
00:19:58,764 --> 00:20:01,699
BRANHAM:
There's also parts of the signal
305
00:20:01,701 --> 00:20:04,335
that have a lot of variation
across individuals.
306
00:20:06,838 --> 00:20:10,341
NARRATOR: This second set
of flashes is personalized.
307
00:20:10,343 --> 00:20:13,978
The timing differs from fly
to fly within a given species.
308
00:20:16,982 --> 00:20:21,252
BRANHAM: Males are telling females,
"I'm a member of this species,
309
00:20:21,254 --> 00:20:25,289
but also,
here's a little bit about me."
310
00:20:25,291 --> 00:20:28,593
It's the females
who actually make the choice.
311
00:20:28,595 --> 00:20:30,661
They can see all these males
flying around flashing,
312
00:20:30,663 --> 00:20:34,398
and they see lots of variation
in those signals,
313
00:20:34,400 --> 00:20:37,969
and some are more sexy
than others,
314
00:20:37,971 --> 00:20:43,541
and so those males get
a flash response by the female.
315
00:20:49,448 --> 00:20:51,449
NARRATOR:
Thanks to their enormous eyes,
316
00:20:51,451 --> 00:20:54,151
shaped over the eons
to detect faint light,
317
00:20:54,153 --> 00:20:57,622
the males see the response
318
00:20:57,624 --> 00:21:01,892
and home in
on the female's location.
319
00:21:03,462 --> 00:21:04,929
BRANHAM:
He'll flash back to her,
320
00:21:04,931 --> 00:21:06,464
she'll flash back to him,
321
00:21:06,466 --> 00:21:08,032
and they'll have
a short dialogue
322
00:21:08,034 --> 00:21:10,368
until the male finds out
where she is exactly,
323
00:21:10,370 --> 00:21:13,871
and he will land
right beside her.
324
00:21:13,873 --> 00:21:15,706
It's Valentine's Day.
325
00:21:17,476 --> 00:21:20,778
NARRATOR: It's the equivalent
of strutting tail feathers,
326
00:21:20,780 --> 00:21:23,581
or chirping and croaking.
327
00:21:23,583 --> 00:21:26,684
To succeed
in the reproduction game,
328
00:21:26,686 --> 00:21:28,986
you've got
to make yourself known,
329
00:21:28,988 --> 00:21:34,225
and light is an effective way
to cut through the chatter.
330
00:21:34,227 --> 00:21:36,193
BRANHAM:
I mean, how can you miss a flash
331
00:21:36,195 --> 00:21:38,296
on a hot summer night?
332
00:21:48,240 --> 00:21:50,241
NARRATOR:
So how do fireflies,
333
00:21:50,243 --> 00:21:52,677
and everything else
that lights up
334
00:21:52,679 --> 00:21:57,948
both on land and at sea,
produce these brilliant flashes?
335
00:21:59,284 --> 00:22:01,786
It turns out
the luminescing beetles
336
00:22:01,788 --> 00:22:05,890
were the torchbearers
for finding that out.
337
00:22:05,892 --> 00:22:09,593
In 1885, a French biologist
338
00:22:09,595 --> 00:22:13,631
working on a firefly cousin
called Pyrophorus
339
00:22:13,633 --> 00:22:15,766
deciphered
the chemistry responsible
340
00:22:15,768 --> 00:22:17,635
for their magical glow.
341
00:22:17,637 --> 00:22:21,238
He determined it's the result
of a reaction
342
00:22:21,240 --> 00:22:23,274
between two chemicals,
343
00:22:23,276 --> 00:22:26,610
which he named
for the fallen angel Lucifer,
344
00:22:26,612 --> 00:22:29,814
the light bearer.
345
00:22:29,816 --> 00:22:32,917
One chemical, luciferin,
acts as the fuel,
346
00:22:32,919 --> 00:22:35,686
kind of like gasoline.
347
00:22:35,688 --> 00:22:38,089
The second, luciferase,
is an enzyme,
348
00:22:38,091 --> 00:22:43,194
which fires the reaction
like a spark plug.
349
00:22:43,196 --> 00:22:44,929
When the chemicals
are mixed together
350
00:22:44,931 --> 00:22:48,733
in the presence of oxygen
and some other key ingredients,
351
00:22:48,735 --> 00:22:50,534
they react,
352
00:22:50,536 --> 00:22:53,404
and the excess energy
is given off as light.
353
00:23:00,112 --> 00:23:03,414
Over the last century,
this light-producing reaction
354
00:23:03,416 --> 00:23:08,452
has been discovered scattered
across the entire natural world,
355
00:23:08,454 --> 00:23:12,590
both above the surface
and beneath the waves.
356
00:23:12,592 --> 00:23:14,892
That's how readily available
these ingredients are.
357
00:23:20,432 --> 00:23:24,535
The actual chemicals differ
from creature to creature,
358
00:23:24,537 --> 00:23:31,142
but the basic mechanism
of fuel and spark is the same
359
00:23:31,144 --> 00:23:36,280
from flies and worms
to jellies and fish,
360
00:23:36,282 --> 00:23:40,084
to snails, even mushrooms.
361
00:23:42,788 --> 00:23:46,490
The reaction is so common,
it has evolved independently
362
00:23:46,492 --> 00:23:49,326
on different branches
of the evolutionary tree
363
00:23:49,328 --> 00:23:52,396
more than 40 separate times.
364
00:23:52,398 --> 00:23:54,732
SPARKS: You find it from
single-celled bacteria
365
00:23:54,734 --> 00:23:57,802
up through things
like starfish, jellyfish,
366
00:23:57,804 --> 00:24:00,171
up through the vertebrates,
fishes.
367
00:24:00,173 --> 00:24:02,773
It's evolved so many times
in so many different lineages.
368
00:24:02,775 --> 00:24:05,376
I mean, if it wasn't important
to the organisms,
369
00:24:05,378 --> 00:24:07,878
you wouldn't see it
all over the tree of life.
370
00:24:09,147 --> 00:24:12,149
NARRATOR: When it comes to
the survival of a species,
371
00:24:12,151 --> 00:24:14,652
nothing holds a candle to light.
372
00:24:24,696 --> 00:24:29,633
But living light turns out
to come in a variety of flavors,
373
00:24:29,635 --> 00:24:32,269
and back on their ship
in the Solomon Islands,
374
00:24:32,271 --> 00:24:35,339
the scientists from the American
Museum of Natural History
375
00:24:35,341 --> 00:24:40,945
are now preparing to study
an altogether different type.
376
00:24:40,947 --> 00:24:43,747
Unlike the bioluminescence
of the deep,
377
00:24:43,749 --> 00:24:47,017
this second kind
found in shallower waters
378
00:24:47,019 --> 00:24:51,088
doesn't produce light
of its own.
379
00:24:51,090 --> 00:24:54,425
Rather, it absorbs light
from an outside source,
380
00:24:54,427 --> 00:24:55,960
soaks in its energy,
381
00:24:55,962 --> 00:24:59,263
and spits it back
as a different color.
382
00:25:01,066 --> 00:25:04,068
It's called biofluorescence.
383
00:25:04,070 --> 00:25:07,404
(dance music playing)
384
00:25:07,406 --> 00:25:10,641
And anyone who's ever danced
under a black light
385
00:25:10,643 --> 00:25:13,744
or watched fingerprints light up
on a crime show
386
00:25:13,746 --> 00:25:15,846
is familiar with the concept.
387
00:25:22,621 --> 00:25:27,558
Fluorescent chemicals
absorb light in a unique way.
388
00:25:27,560 --> 00:25:30,561
Down at the atomic level,
light jolts electrons
389
00:25:30,563 --> 00:25:33,564
into more energetic orbits
around the nucleus.
390
00:25:35,367 --> 00:25:37,434
When they fall back
to their original state
391
00:25:37,436 --> 00:25:39,770
a few billionths
of a second later,
392
00:25:39,772 --> 00:25:43,774
the electrons re-emit,
or fluoresce, the light back
393
00:25:43,776 --> 00:25:48,279
at a lower energy level,
giving off a different color.
394
00:25:51,249 --> 00:25:55,753
Fluorescent animals
work the same way,
395
00:25:55,755 --> 00:25:59,256
only their special chemicals,
typically fluorescent proteins,
396
00:25:59,258 --> 00:26:01,825
are built into their skin
and other tissues.
397
00:26:08,033 --> 00:26:09,867
PIERIBONE: Biofluorescence
is an odd property
398
00:26:09,869 --> 00:26:12,536
because the animals don't
actually produce any light.
399
00:26:12,538 --> 00:26:13,737
You shine one color light
400
00:26:13,739 --> 00:26:15,406
and they'll produce
a second color of light.
401
00:26:15,408 --> 00:26:18,409
And it's a pretty rare
phenomenon.
402
00:26:18,411 --> 00:26:20,945
NARRATOR: That's because
unlike bioluminescence,
403
00:26:20,947 --> 00:26:25,015
biofluorescence requires
a special set of conditions
404
00:26:25,017 --> 00:26:26,951
to occur in nature.
405
00:26:29,888 --> 00:26:33,724
It needs sunlight to make light,
406
00:26:33,726 --> 00:26:36,660
but not sunlight as we know it
up on the surface.
407
00:26:40,065 --> 00:26:41,732
When it hits earth,
408
00:26:41,734 --> 00:26:44,535
sunlight contains all the colors
of the rainbow,
409
00:26:44,537 --> 00:26:48,772
as light going through a prism
reveals.
410
00:26:48,774 --> 00:26:50,441
Eacholor is the result
411
00:26:50,443 --> 00:26:52,509
of a different wavelength
of energy.
412
00:26:55,614 --> 00:26:59,416
But once the light hits water,
things get interesting.
413
00:27:02,220 --> 00:27:05,322
Water acts like a filter,
and the different wavelengths
414
00:27:05,324 --> 00:27:09,259
are only able to penetrate
to certain depths.
415
00:27:09,261 --> 00:27:13,397
Long wavelengths, like reds
and oranges, fade out first,
416
00:27:13,399 --> 00:27:18,302
then yellows and greens,
417
00:27:18,304 --> 00:27:21,171
and then finally, a sea of blue.
418
00:27:23,108 --> 00:27:25,943
And this pure blue light
419
00:27:25,945 --> 00:27:29,313
turns out to be the perfect
trigger for fluorescence.
420
00:27:32,417 --> 00:27:34,251
PIERIBONE:
So they take the blue light
421
00:27:34,253 --> 00:27:35,919
that's coming to them
in the ocean
422
00:27:35,921 --> 00:27:37,921
and they convert it
to greens and reds,
423
00:27:37,923 --> 00:27:41,725
and that gives them this color,
this contrast.
424
00:27:44,663 --> 00:27:47,064
NARRATOR: Depending on their
chemical composition,
425
00:27:47,066 --> 00:27:50,501
different fluorescent proteins
give off different colors,
426
00:27:50,503 --> 00:27:53,771
all of which can be hard to see.
427
00:27:53,773 --> 00:28:00,010
Without special filters,
visible light can wash it out.
428
00:28:00,012 --> 00:28:04,081
That may explain why it's gone
unnoticed for so long.
429
00:28:09,087 --> 00:28:12,156
How animals use fluorescence
is still a mystery.
430
00:28:15,593 --> 00:28:19,396
In corals, where fluorescence
seems to be the most prevalent,
431
00:28:19,398 --> 00:28:22,299
it may be used as a kind
of protective sunscreen,
432
00:28:22,301 --> 00:28:24,968
deflecting harmful UV light
433
00:28:24,970 --> 00:28:28,205
or absorbing dangerous
byproducts of photosynthesis.
434
00:28:31,810 --> 00:28:34,378
PIERIBONE: So the coral
is this piece of rock
435
00:28:34,380 --> 00:28:36,714
with a skin coat
of a few cell layers on top,
436
00:28:36,716 --> 00:28:38,849
and in that layer, it's packed
with this fluorescent protein.
437
00:28:38,851 --> 00:28:40,718
These animals
are doing a lot of work
438
00:28:40,720 --> 00:28:42,319
to produce
a lot of this protein.
439
00:28:42,321 --> 00:28:44,401
That's the mystery:
why are they doing it?
440
00:28:50,195 --> 00:28:53,230
NARRATOR: For years, fluorescence
was thought to be confined
441
00:28:53,232 --> 00:28:55,966
mainly to corals
and some jellyfish.
442
00:28:57,902 --> 00:29:02,573
But recent finds reveal
it may be much more widespread.
443
00:29:04,476 --> 00:29:08,479
And in 2012, while shooting
a mosaic of fluorescing corals
444
00:29:08,481 --> 00:29:10,547
off the Cayman Islands,
445
00:29:10,549 --> 00:29:14,351
David Gruber and John Sparks
had a big "Eureka!" moment.
446
00:29:15,687 --> 00:29:17,321
GRUBER:
It's like 10:00 at night,
447
00:29:17,323 --> 00:29:20,691
we're diving on the coral wall,
we're about 80 feet down.
448
00:29:20,693 --> 00:29:24,461
We're photographing lots of
little montages of a coral reef
449
00:29:24,463 --> 00:29:26,230
and we stitch it together,
450
00:29:26,232 --> 00:29:28,031
and when we got back
to our lab at night
451
00:29:28,033 --> 00:29:30,768
and we're looking
through our photographs,
452
00:29:30,770 --> 00:29:34,805
and there it is, like, this
bright green fluorescent eel
453
00:29:34,807 --> 00:29:36,673
in one of our photographs.
454
00:29:39,611 --> 00:29:42,513
NARRATOR: It was the first
time they'd ever seen
455
00:29:42,515 --> 00:29:45,816
a fluorescent fish in the wild.
456
00:29:45,818 --> 00:29:47,484
SPARKS: We said, "What
the heck is that?"
457
00:29:47,486 --> 00:29:48,952
and we thought it was a joke,
458
00:29:48,954 --> 00:29:50,420
that the guy,
the photographer who was with us
459
00:29:50,422 --> 00:29:52,456
had Photoshopped something
and was just playing with us.
460
00:29:52,458 --> 00:29:54,091
I'm turning this light up?
461
00:29:54,093 --> 00:29:55,626
GRUBER: We didn't
believe it at the time.
462
00:29:55,628 --> 00:29:56,960
We just checked our lenses.
463
00:29:56,962 --> 00:29:58,629
We thought there was some kind
of glitch in the camera.
464
00:29:58,631 --> 00:30:01,698
Essentially, we got photobombed
465
00:30:01,700 --> 00:30:04,568
by a reclusive
green fluorescent eel.
466
00:30:04,570 --> 00:30:06,670
Can we get in
on these guys down here?
467
00:30:06,672 --> 00:30:09,940
NARRATOR: The eel opened up a whole
new world for the scientists.
468
00:30:09,942 --> 00:30:11,942
It just keeps turning it on.
469
00:30:11,944 --> 00:30:15,546
NARRATOR: Armed with blue
lights and yellow filters,
470
00:30:15,548 --> 00:30:19,183
the team started seeking out
fluorescence closer to home,
471
00:30:19,185 --> 00:30:20,818
in aquariums.
472
00:30:20,820 --> 00:30:22,586
Hey, this guy right here.
473
00:30:22,588 --> 00:30:27,391
NARRATOR: They found it everywhere,
all the way up the food chain.
474
00:30:27,393 --> 00:30:29,793
Man, check that out.
475
00:30:31,329 --> 00:30:33,096
NARRATOR:
In seahorses...
476
00:30:37,135 --> 00:30:39,236
Rays...
477
00:30:42,540 --> 00:30:45,075
...and even some sharks.
478
00:30:48,279 --> 00:30:49,613
MAN:
They're going pretty good!
479
00:30:49,615 --> 00:30:50,614
MAN:
Did you get it?
480
00:30:50,616 --> 00:30:52,783
I saw the shark glowing
like crazy.
481
00:30:52,785 --> 00:30:58,255
NARRATOR: All have been hiding
their true colors in plain sight.
482
00:30:58,257 --> 00:30:59,890
MAN: Whoa, there it is,
the fluorescent one.
483
00:30:59,892 --> 00:31:01,391
Look at it,
you can see it from here.
484
00:31:01,393 --> 00:31:03,060
SPARKS: We're kind of
looking back and going,
485
00:31:03,062 --> 00:31:05,729
"Why didn't anybody see this?"
and you know,
486
00:31:05,731 --> 00:31:08,265
you probably just think
it's a bright fish, right?
487
00:31:08,267 --> 00:31:11,335
You don't know it's fluorescing
until you start looking.
488
00:31:11,337 --> 00:31:14,171
Once you start looking,
then it's all over the place.
489
00:31:22,113 --> 00:31:24,948
NARRATOR: To find out how
prevalent fluorescence is,
490
00:31:24,950 --> 00:31:27,985
the scientists needed to move
beyond aquariums
491
00:31:27,987 --> 00:31:30,220
and study it in the wild.
492
00:31:37,028 --> 00:31:39,763
DIVER: There's a lot of nice
ledges kind of cut into the reefs.
493
00:31:39,765 --> 00:31:43,700
SPARKS: These little guys
are gobies, or blennies.
494
00:31:43,702 --> 00:31:44,868
What's nice about these guys is
495
00:31:44,870 --> 00:31:46,336
almost all these little groups
are fluorescent,
496
00:31:46,338 --> 00:31:47,371
really fluorescent.
497
00:31:47,373 --> 00:31:49,840
These fish here
look exactly alike,
498
00:31:49,842 --> 00:31:51,475
but they're all
different species.
499
00:31:51,477 --> 00:31:53,310
And if you put them
under fluorescent light,
500
00:31:53,312 --> 00:31:54,678
they look really distinct.
501
00:31:56,214 --> 00:31:59,082
NARRATOR: In the monotonous,
blue underwater world,
502
00:31:59,084 --> 00:32:01,218
the fluorescent splotches
and stripes
503
00:32:01,220 --> 00:32:03,520
may act as secret barcodes,
504
00:32:03,522 --> 00:32:06,523
signaling fishes' identity
to potential mates.
505
00:32:17,235 --> 00:32:19,903
It's an idea made
even more compelling
506
00:32:19,905 --> 00:32:23,941
when scientists look closely
at the fishes' eyes.
507
00:32:23,943 --> 00:32:28,712
Unlike human eyes,
many fluorescent fish
508
00:32:28,714 --> 00:32:32,649
seem to have built-in
yellow filters.
509
00:32:32,651 --> 00:32:37,020
The filters block out
the ambient blue in the water,
510
00:32:37,022 --> 00:32:40,424
letting the vibrant colors
of fluorescence stand out.
511
00:32:43,161 --> 00:32:47,698
This world
that's been hidden to us
512
00:32:47,700 --> 00:32:49,566
may be plain as day to the fish.
513
00:32:52,971 --> 00:32:54,471
GRUBER:
The coral reef
514
00:32:54,473 --> 00:32:56,573
is one of the most competitive
environments in the world.
515
00:32:56,575 --> 00:32:59,843
It's one of the most biodiverse.
516
00:32:59,845 --> 00:33:02,045
Everybody's fighting for space,
517
00:33:02,047 --> 00:33:04,715
so by having this ability
to fluoresce,
518
00:33:04,717 --> 00:33:06,616
they're creating a richer world
for them.
519
00:33:06,618 --> 00:33:08,418
And now for the first time,
520
00:33:08,420 --> 00:33:10,320
we're beginning
to see this world
521
00:33:10,322 --> 00:33:12,756
that they've been seeing
for millions of years.
522
00:33:12,758 --> 00:33:14,424
PIERIBONE:
Yeah, let's test it.
523
00:33:14,426 --> 00:33:16,546
(faking German accent):
Bring in ze patient!
524
00:33:17,395 --> 00:33:19,496
NARRATOR: For neuroscientist
Vincent Pieribone,
525
00:33:19,498 --> 00:33:21,965
the discovery
of new fluorescent animals
526
00:33:21,967 --> 00:33:23,467
is particularly exciting.
527
00:33:23,469 --> 00:33:25,168
Impressive.
528
00:33:25,170 --> 00:33:27,270
Wow, it's brilliant, brilliant.
529
00:33:27,272 --> 00:33:30,574
NARRATOR: He's especially
interested in the proteins
530
00:33:30,576 --> 00:33:34,478
that make the fish fluoresce.
531
00:33:34,480 --> 00:33:38,281
He's hoping to use them
to light up living nerve cells
532
00:33:38,283 --> 00:33:42,085
and ultimately
map the human brain.
533
00:33:42,087 --> 00:33:45,188
PIERIBONE: The inside of
the brain is a black box.
534
00:33:45,190 --> 00:33:48,325
It's probably the most amazing
instrument on the entire earth.
535
00:33:48,327 --> 00:33:50,827
Nothing else comes close to
the ability of the human brain.
536
00:33:50,829 --> 00:33:52,162
And yet we don't have
537
00:33:52,164 --> 00:33:56,767
even a very thin understanding
of how it works.
538
00:33:56,769 --> 00:34:01,071
So we have been in the ocean
looking for proteins
539
00:34:01,073 --> 00:34:05,208
that we can put into nerve cells
so that those nerve cells glow.
540
00:34:05,210 --> 00:34:06,910
And we interpret
that information
541
00:34:06,912 --> 00:34:09,212
and find out how the brain
is doing what it does.
542
00:34:10,548 --> 00:34:13,050
NARRATOR: Scientists use
fluorescent protein
543
00:34:13,052 --> 00:34:15,318
to light up the inner workings
of cells.
544
00:34:18,489 --> 00:34:20,657
The initial work began
545
00:34:20,659 --> 00:34:23,693
with a green fluorescent
protein, or GFP,
546
00:34:23,695 --> 00:34:27,264
which was initially isolated
from this jellyfish.
547
00:34:30,034 --> 00:34:31,768
GRUBER:
Green fluorescent protein
548
00:34:31,770 --> 00:34:33,804
is like a little
bicycle reflector
549
00:34:33,806 --> 00:34:36,173
that you could tag
onto any protein,
550
00:34:36,175 --> 00:34:38,108
and then you'll watch
in real time
551
00:34:38,110 --> 00:34:41,378
that protein moving
about the cell in a living cell.
552
00:34:42,880 --> 00:34:45,015
NARRATOR: To do it,
scientists take the gene
553
00:34:45,017 --> 00:34:48,452
that carries the recipe to make
green fluorescent protein
554
00:34:48,454 --> 00:34:52,589
and insert it into cells.
555
00:34:52,591 --> 00:34:55,125
Once the genetic
instructions are inside,
556
00:34:55,127 --> 00:34:58,495
the cells make the protein.
557
00:34:58,497 --> 00:35:01,798
When scientists hit
the organisms with blue light,
558
00:35:01,800 --> 00:35:03,760
the targeted cells
fluoresce green.
559
00:35:06,304 --> 00:35:08,305
GRUBER:
So this revolutionized
560
00:35:08,307 --> 00:35:12,476
our ability to see
at the protein level
561
00:35:12,478 --> 00:35:14,077
inside living cells.
562
00:35:15,980 --> 00:35:19,883
NARRATOR: GFP was a Nobel
Prize-winning discovery,
563
00:35:19,885 --> 00:35:23,987
bringing to light everything
from the way cancer spreads...
564
00:35:23,989 --> 00:35:25,922
These are malignant cells
565
00:35:25,924 --> 00:35:29,693
traveling through
blood vessels...
566
00:35:29,695 --> 00:35:33,430
To how viruses infect
and replicate.
567
00:35:34,899 --> 00:35:37,267
Here is HIV, the AIDS virus,
568
00:35:37,269 --> 00:35:41,238
spreading from one cell
to another.
569
00:35:41,240 --> 00:35:44,508
If scientists attach GFP
to virus-resistant genes
570
00:35:44,510 --> 00:35:50,514
and insert them into the DNA
of animals like mice and cats,
571
00:35:50,516 --> 00:35:54,050
they can even assess
potential cures for AIDS,
572
00:35:54,052 --> 00:35:58,255
lighting up entire creatures
in the process.
573
00:35:58,257 --> 00:36:00,891
PIERIBONE: So GFP was a
beautiful discovery.
574
00:36:00,893 --> 00:36:04,227
It allowed people
to see cells in green.
575
00:36:04,229 --> 00:36:06,709
So it makes essentially what's
completely invisible, visible.
576
00:36:08,332 --> 00:36:11,368
NARRATOR: Scientists have
since manipulated GFP
577
00:36:11,370 --> 00:36:13,370
to fluoresce different colors...
578
00:36:17,241 --> 00:36:21,044
...enabling them to tag
different cells at once.
579
00:36:21,046 --> 00:36:23,413
MAN:
Very green.
580
00:36:23,415 --> 00:36:25,315
Yeah, it's beautiful.
581
00:36:25,317 --> 00:36:26,983
NARRATOR:
They've also gone beyond that,
582
00:36:26,985 --> 00:36:30,487
mining the deep
for new fluorescent proteins
583
00:36:30,489 --> 00:36:34,591
and finding colors
across the light spectrum.
584
00:36:35,760 --> 00:36:39,229
But human brain tissue presents
a unique challenge.
585
00:36:39,231 --> 00:36:41,498
It's quite dense,
586
00:36:41,500 --> 00:36:43,700
and none of the colors
discovered so far
587
00:36:43,702 --> 00:36:46,603
could easily pass through it.
588
00:36:46,605 --> 00:36:48,605
So neuroscientists like Vincent
589
00:36:48,607 --> 00:36:51,942
have been looking for colors
with longer wavelengths,
590
00:36:51,944 --> 00:36:54,611
like far reds and infrareds,
that can.
591
00:36:56,681 --> 00:36:59,683
PIERIBONE: Reds are a little bit
better, they go a little bit deeper,
592
00:36:59,685 --> 00:37:02,219
but infrared will pass
all the way through the tissue.
593
00:37:02,221 --> 00:37:03,987
So for neuroscientists,
594
00:37:03,989 --> 00:37:07,724
the holy grail has always been
as far red as possible.
595
00:37:07,726 --> 00:37:08,725
Yeah, exactly.
596
00:37:08,727 --> 00:37:10,360
Got it!
597
00:37:10,362 --> 00:37:13,363
PIERIBONE: So getting these things
out of the ocean is really key.
598
00:37:13,365 --> 00:37:14,998
It's the only place
they've ever been found,
599
00:37:15,000 --> 00:37:17,133
and we're back here again
looking for ones
600
00:37:17,135 --> 00:37:20,303
with different colors,
different intensities.
601
00:37:20,305 --> 00:37:22,706
So that's our mission.
602
00:37:22,708 --> 00:37:26,443
NARRATOR: To find the glowing
creatures Vincent needs,
603
00:37:26,445 --> 00:37:28,411
the team dives at night,
604
00:37:28,413 --> 00:37:32,082
when there is no natural light
to obscure their vision.
605
00:37:32,084 --> 00:37:35,852
GRUBER: We are getting ready
for a scoping mission.
606
00:37:35,854 --> 00:37:38,188
We'll be looking
for biofluorescence
607
00:37:38,190 --> 00:37:39,689
out here on the reef,
608
00:37:39,691 --> 00:37:42,292
and we're going to be using
this camera.
609
00:37:45,630 --> 00:37:48,665
NARRATOR: To stimulate fluorescence,
they'll shine blue lights
610
00:37:48,667 --> 00:37:52,102
that match the blue
found underwater during the day
611
00:37:52,104 --> 00:37:54,304
and look through yellow filters,
612
00:37:54,306 --> 00:37:57,207
just like the ones
the fish see through,
613
00:37:57,209 --> 00:37:59,442
to block out the blue light
they're shining.
614
00:38:02,213 --> 00:38:03,880
GRUBER:
So this way, we can be sure
615
00:38:03,882 --> 00:38:05,382
that everything we see in here,
616
00:38:05,384 --> 00:38:07,517
the different critters
that we're looking at,
617
00:38:07,519 --> 00:38:10,153
are truly biofluorescent.
618
00:38:10,155 --> 00:38:11,154
Ready to roll?
619
00:38:11,156 --> 00:38:12,489
Yep.
620
00:38:28,039 --> 00:38:30,573
NARRATOR: The divers
have to get pretty deep,
621
00:38:30,575 --> 00:38:34,010
about 100 feet down,
622
00:38:34,012 --> 00:38:37,147
approaching that special zone
that during the day
623
00:38:37,149 --> 00:38:39,282
is awash in blue,
624
00:38:39,284 --> 00:38:42,852
the most likely spot to find
fluorescent animals.
625
00:38:48,826 --> 00:38:51,928
The reef is dramatic,
even under blue light.
626
00:38:54,865 --> 00:38:59,436
But when the team
looks through their filters,
627
00:38:59,438 --> 00:39:01,871
a different world
comes into view.
628
00:39:07,511 --> 00:39:09,779
A technicolor dreamscape.
629
00:39:56,427 --> 00:39:58,928
NARRATOR:
Vincent and David scan the reef
630
00:39:58,930 --> 00:40:01,464
for novel sources
of fluorescence.
631
00:40:03,734 --> 00:40:06,002
PIERIBONE: We look around in
the reef, we swim around,
632
00:40:06,004 --> 00:40:08,138
and we identify something:
everything looks black
633
00:40:08,140 --> 00:40:10,206
except those animals that are
sending light back at us,
634
00:40:10,208 --> 00:40:11,241
and there's coral
635
00:40:11,243 --> 00:40:13,510
and there's crinoids
and there's anemones
636
00:40:13,512 --> 00:40:16,112
and there's fish
all giving this back.
637
00:40:16,114 --> 00:40:18,415
And I can take a tiny bit
of a single animal,
638
00:40:18,417 --> 00:40:20,283
or a tiny part of an animal,
639
00:40:20,285 --> 00:40:21,718
and you can sequence
its entire genome.
640
00:40:21,720 --> 00:40:23,353
Now you have everything
you need to know
641
00:40:23,355 --> 00:40:24,555
about the animal genetically.
642
00:40:26,457 --> 00:40:30,126
NARRATOR: They're especially
interested in glowing red animals,
643
00:40:30,128 --> 00:40:33,997
and there's no shortage of them
down here.
644
00:40:33,999 --> 00:40:39,369
But not all red animals
are useful.
645
00:40:39,371 --> 00:40:42,605
Some depend on multiple proteins
to produce the color,
646
00:40:42,607 --> 00:40:45,475
making them too complicated
to study the brain.
647
00:40:48,646 --> 00:40:50,380
To hedge their bets,
648
00:40:50,382 --> 00:40:53,483
they grab as many interesting
samples as they can.
649
00:40:55,786 --> 00:40:57,120
MAN:
Top of the evening to you.
650
00:40:57,122 --> 00:40:59,155
Hey, mate, you wanna kill
the engine for me?
651
00:40:59,157 --> 00:41:01,858
You're enough off the wall.
652
00:41:01,860 --> 00:41:02,892
You had some friends
out there, huh?
653
00:41:02,894 --> 00:41:05,862
Yeah, it was really sharky
out there tonight.
654
00:41:05,864 --> 00:41:09,332
(all talking excitedly)
655
00:41:09,334 --> 00:41:11,201
This one, this thing right here,
the leafy thing right here,
656
00:41:11,203 --> 00:41:12,535
unbelievable, you see it?
657
00:41:12,537 --> 00:41:13,870
Like a Christmas tree.
658
00:41:13,872 --> 00:41:17,373
And I got another one of these
guys and I got a tunicate.
659
00:41:17,375 --> 00:41:19,008
Let's get them back
and look at them.
660
00:41:19,010 --> 00:41:20,343
Yeah, that was unbelievable.
661
00:41:25,516 --> 00:41:27,417
NARRATOR:
Back at the ship's lab,
662
00:41:27,419 --> 00:41:30,720
the scientists anxiously
examine their catch,
663
00:41:30,722 --> 00:41:35,425
once again simulating the ocean
blue with their special lights
664
00:41:35,427 --> 00:41:37,727
and peering through
their yellow filters.
665
00:41:37,729 --> 00:41:39,729
MAN:
And this is what?
666
00:41:39,731 --> 00:41:42,565
This is the soft coral, right?
667
00:41:42,567 --> 00:41:44,200
Yeah, they are.
668
00:41:46,303 --> 00:41:47,804
All right,
so let's go through here.
669
00:41:47,806 --> 00:41:50,640
Oh, my goodness, it's very nice.
670
00:41:50,642 --> 00:41:52,141
NARRATOR:
Anything promising
671
00:41:52,143 --> 00:41:54,310
gets a closer look
under the microscope.
672
00:41:56,380 --> 00:41:57,547
What is it?
673
00:41:57,549 --> 00:41:59,349
That's crazy,
you think it's a coral?
674
00:41:59,351 --> 00:42:00,984
No, and it's only
on small parts.
675
00:42:00,986 --> 00:42:03,520
I wish this boat
wasn't shaking so much.
676
00:42:03,522 --> 00:42:04,921
(laughs):
Somebody radio up.
677
00:42:04,923 --> 00:42:07,723
MAN: Somebody radio up
to stop moving the boat.
678
00:42:08,692 --> 00:42:10,960
NARRATOR: Not everything they collect
turns out to be fluorescent.
679
00:42:10,962 --> 00:42:13,363
MAN:
Nothing.
680
00:42:13,365 --> 00:42:15,365
It's not fluorescent at all.
681
00:42:15,367 --> 00:42:16,399
No.
682
00:42:16,401 --> 00:42:18,635
Not a single bit.
683
00:42:21,071 --> 00:42:25,875
NARRATOR: They do isolate several
interesting green specimens,
684
00:42:25,877 --> 00:42:28,111
photographing
and freezing away each one.
685
00:42:32,917 --> 00:42:35,852
And then, finally...
686
00:42:35,854 --> 00:42:37,787
There you go!
687
00:42:39,857 --> 00:42:41,758
NARRATOR:
Red.
688
00:42:41,760 --> 00:42:45,061
PIERIBONE:
Ah, that's beautiful.
689
00:42:45,063 --> 00:42:47,297
That's the red fluorescent
protein we're hunting for.
690
00:42:47,299 --> 00:42:48,731
We're shining blue light on it,
691
00:42:48,733 --> 00:42:50,567
but what you're getting
is red light coming out.
692
00:42:50,569 --> 00:42:52,735
So that's the whole...
693
00:42:52,737 --> 00:42:55,038
that's the trick
to fluorescence.
694
00:42:55,040 --> 00:42:56,706
Check that out.
695
00:42:56,708 --> 00:42:58,775
Looks like fire.
696
00:42:58,777 --> 00:43:01,144
NARRATOR:
The scientists won't know
697
00:43:01,146 --> 00:43:03,346
if they can isolate
the red fluorescent proteins
698
00:43:03,348 --> 00:43:07,450
until they get back
to their labs onshore.
699
00:43:07,452 --> 00:43:11,955
Even if they can,
it's still a long shot
700
00:43:11,957 --> 00:43:14,357
whether they can turn them
into useful probes
701
00:43:14,359 --> 00:43:16,025
to study the brain.
702
00:43:16,027 --> 00:43:17,427
I'm getting pumped up now.
703
00:43:18,963 --> 00:43:20,530
Look at that.
704
00:43:20,532 --> 00:43:21,831
Good stuff.
705
00:43:21,833 --> 00:43:23,933
Isn't that awesome?
706
00:43:23,935 --> 00:43:27,103
NARRATOR: But for now, this
is as close to success
707
00:43:27,105 --> 00:43:30,406
as they allow themselves
to hope for.
708
00:43:30,408 --> 00:43:33,710
PIERIBONE:
Science must march forward!
709
00:43:40,584 --> 00:43:43,419
NARRATOR: Back in New York,
John Sparks and David Gruber
710
00:43:43,421 --> 00:43:45,088
rescue their samples
from the deep freeze
711
00:43:45,090 --> 00:43:49,993
at the American Museum
of Natural History
712
00:43:49,995 --> 00:43:53,997
and begin the painstaking
process of carefully examining
713
00:43:53,999 --> 00:43:57,133
each of their hundreds
of fluorescent specimens.
714
00:44:01,805 --> 00:44:05,208
From one eel
just a few years ago,
715
00:44:05,210 --> 00:44:08,244
the scientists
have now discovered fluorescence
716
00:44:08,246 --> 00:44:12,649
in more than 200 species
of fish.
717
00:44:12,651 --> 00:44:16,185
SPARKS: Biofluorescence is found
all over the tree of life,
718
00:44:16,187 --> 00:44:18,655
but just like you see
for bioluminescence,
719
00:44:18,657 --> 00:44:20,323
it's like somebody just took it
and threw it at the tree
720
00:44:20,325 --> 00:44:21,624
and it kind of stuck
in certain places,
721
00:44:21,626 --> 00:44:22,859
no clear pattern to it.
722
00:44:22,861 --> 00:44:26,329
NARRATOR: Now it's a matter
of extracting the proteins
723
00:44:26,331 --> 00:44:30,800
from the diverse creatures,
starting with a bit of tissue.
724
00:44:30,802 --> 00:44:33,236
GRUBER:
We only want to isolate
725
00:44:33,238 --> 00:44:37,206
the little bit of the tissue
that is fluorescent
726
00:44:37,208 --> 00:44:38,374
and nothing else.
727
00:44:38,376 --> 00:44:39,575
Let's go from over here.
728
00:44:39,577 --> 00:44:40,743
Extraneous tissue, yeah.
729
00:44:40,745 --> 00:44:41,944
Here to here.
730
00:44:41,946 --> 00:44:43,079
Yeah.
731
00:44:43,081 --> 00:44:44,647
Perfect.
732
00:44:44,649 --> 00:44:46,215
Now let's go into here.
733
00:44:48,318 --> 00:44:49,886
Beautiful.
734
00:44:49,888 --> 00:44:53,256
NARRATOR: From this,
they isolate the genes
735
00:44:53,258 --> 00:44:57,493
that make the proteins causing
the critters to fluoresce,
736
00:44:57,495 --> 00:45:03,199
and then send any promising
targets off to Vincent.
737
00:45:03,201 --> 00:45:05,435
PIERIBONE: This is exactly
how a plate should look,
738
00:45:05,437 --> 00:45:06,869
nice and distributed.
739
00:45:06,871 --> 00:45:08,438
They should be far enough apart.
740
00:45:08,440 --> 00:45:11,874
NARRATOR: At Yale, Vincent
and his colleagues
741
00:45:11,876 --> 00:45:17,146
try to turn them into tools
to understand the brain.
742
00:45:17,148 --> 00:45:19,482
Using genetic engineering,
743
00:45:19,484 --> 00:45:21,751
they fuse
the fluorescent proteins
744
00:45:21,753 --> 00:45:24,287
to others that are sensitive
to voltage,
745
00:45:24,289 --> 00:45:27,056
the language of brain cells.
746
00:45:27,058 --> 00:45:28,324
PIERIBONE:
So that'll run for an hour.
747
00:45:28,326 --> 00:45:29,659
Okay.
748
00:45:29,661 --> 00:45:31,661
NARRATOR:
They've recently done this
749
00:45:31,663 --> 00:45:34,831
with green fluorescent protein
and fruit fly brains,
750
00:45:34,833 --> 00:45:37,366
which are less dense than ours.
751
00:45:37,368 --> 00:45:40,103
PIERIBONE: So we need a protein
that can go from dim to bright
752
00:45:40,105 --> 00:45:42,438
very quickly...
Up, down, up, down, up, down...
753
00:45:42,440 --> 00:45:44,674
To be able to follow
these rapid transitions
754
00:45:44,676 --> 00:45:46,796
in electrical signals
that we see in a cell.
755
00:45:48,312 --> 00:45:50,913
NARRATOR: They then insert the
glowing, voltage-sensitive protein
756
00:45:50,915 --> 00:45:53,549
into the flies.
757
00:45:53,551 --> 00:45:56,452
Under a special microscope,
758
00:45:56,454 --> 00:46:00,456
they can now watch
as the flies think.
759
00:46:03,360 --> 00:46:07,530
Each time a neuron fires,
the voltage changes,
760
00:46:07,532 --> 00:46:12,101
and so does the intensity
of the glow.
761
00:46:12,103 --> 00:46:13,936
PIERIBONE:
To be honest with you,
762
00:46:13,938 --> 00:46:16,038
it's absolutely exciting
to sit there
763
00:46:16,040 --> 00:46:18,741
and see a brain of an organism
as the animal is thinking
764
00:46:18,743 --> 00:46:21,511
and watching it as it happens
in real time.
765
00:46:25,616 --> 00:46:27,216
NARRATOR:
Unlike conventional scans,
766
00:46:27,218 --> 00:46:30,386
which measure activity
across the entire brain,
767
00:46:30,388 --> 00:46:33,256
these flashes of light and color
768
00:46:33,258 --> 00:46:35,324
are some of the first
direct images
769
00:46:35,326 --> 00:46:38,427
of electrical activity
of individual neurons
770
00:46:38,429 --> 00:46:42,799
in a living, thinking brain,
the basis of all behavior.
771
00:46:45,269 --> 00:46:47,837
Here's a fly being presented
with a new smell.
772
00:46:51,942 --> 00:46:53,209
When going to sleep.
773
00:46:56,180 --> 00:46:58,648
When waking up.
774
00:47:01,518 --> 00:47:04,120
So far, the scientists
have managed to image
775
00:47:04,122 --> 00:47:06,856
just a handful of neurons,
a far cry
776
00:47:06,858 --> 00:47:11,994
from the 86-odd billion
powering the human brain.
777
00:47:11,996 --> 00:47:13,496
But to Vincent,
778
00:47:13,498 --> 00:47:15,665
it's a profound step
on the way to decoding
779
00:47:15,667 --> 00:47:19,335
how our brains
govern our actions
780
00:47:19,337 --> 00:47:22,271
and conjure our thoughts.
781
00:47:22,273 --> 00:47:24,373
PIERIBONE: Ultimately,
that nerve cell activity
782
00:47:24,375 --> 00:47:28,110
is what gives us consciousness,
memory, behavior, personality.
783
00:47:28,112 --> 00:47:30,279
Everything we do,
it derives from that,
784
00:47:30,281 --> 00:47:32,982
so not understanding that
is an absolute crime.
785
00:47:32,984 --> 00:47:35,551
And now with these probes
that we're developing,
786
00:47:35,553 --> 00:47:37,753
we can now start to record
every single neuron.
787
00:47:41,692 --> 00:47:43,059
NARRATOR:
To map anything
788
00:47:43,061 --> 00:47:45,261
more sophisticated
than a fly, though,
789
00:47:45,263 --> 00:47:49,565
Vincent is missing
one key ingredient:
790
00:47:49,567 --> 00:47:53,302
those red fluorescent proteins.
791
00:47:53,304 --> 00:47:57,473
Fly brains are tiny
and relatively transparent.
792
00:47:57,475 --> 00:48:02,245
Green fluorescent protein
can penetrate them easily.
793
00:48:02,247 --> 00:48:05,348
But for bigger,
more complex brains,
794
00:48:05,350 --> 00:48:09,452
scientists still need infrared.
795
00:48:09,454 --> 00:48:11,454
PIERIBONE:
Again, the goal of the far red
796
00:48:11,456 --> 00:48:15,725
is to have this ability
to shine far red light,
797
00:48:15,727 --> 00:48:17,860
which penetrates
through tissue better.
798
00:48:17,862 --> 00:48:19,996
So red is just really
what everybody wants.
799
00:48:22,165 --> 00:48:23,566
NARRATOR:
It'll take years to fish
800
00:48:23,568 --> 00:48:28,070
through the hundreds of samples
recovered in the Solomons.
801
00:48:28,072 --> 00:48:30,973
They're still working to purify
the bright red coral
802
00:48:30,975 --> 00:48:33,576
that had them so excited
on the ship.
803
00:48:35,646 --> 00:48:38,347
But one of the fish
they picked up,
804
00:48:38,349 --> 00:48:40,216
a species of lizardfish,
805
00:48:40,218 --> 00:48:42,551
seems to fluoresce far red light
quite well.
806
00:48:45,589 --> 00:48:48,524
The team has just determined
that a single protein
807
00:48:48,526 --> 00:48:51,427
is responsible
for the red fluorescence,
808
00:48:51,429 --> 00:48:55,698
and Vincent hopes to soon
engineer it to light up neurons.
809
00:48:57,434 --> 00:48:59,602
PIERIBONE: These tools
that we're developing
810
00:48:59,604 --> 00:49:01,804
and other labs are developing
are giving us a chance
811
00:49:01,806 --> 00:49:03,706
to witness those things
we've wanted to witness
812
00:49:03,708 --> 00:49:06,375
since neuroscience began
100 years ago,
813
00:49:06,377 --> 00:49:09,312
but we're for the first time
being able to see the process
814
00:49:09,314 --> 00:49:10,546
as it happens.
815
00:49:12,049 --> 00:49:13,916
NARRATOR: And the promise
of glowing creatures
816
00:49:13,918 --> 00:49:16,819
isn't limited to the brain.
817
00:49:19,623 --> 00:49:22,058
Around the world,
other researchers
818
00:49:22,060 --> 00:49:24,961
are harnessing them
in many different ways.
819
00:49:29,566 --> 00:49:34,036
In Florida, Edie Widder
is using bioluminescent bacteria
820
00:49:34,038 --> 00:49:36,739
to shine a light on pollution.
821
00:49:39,676 --> 00:49:42,611
Toxins in polluted water
happen to interfere
822
00:49:42,613 --> 00:49:45,481
with the bacteria's ability
to produce light.
823
00:49:47,217 --> 00:49:49,185
WIDDER:
The more polluted it is,
824
00:49:49,187 --> 00:49:50,686
the more the light dims,
825
00:49:50,688 --> 00:49:52,655
so you get a relative measure
of toxicity.
826
00:49:52,657 --> 00:49:57,093
NARRATOR: By taking sediment
samples in threatened estuaries,
827
00:49:57,095 --> 00:49:59,695
mixing it with the
bioluminescent bacteria
828
00:49:59,697 --> 00:50:02,031
and measuring the light
they give off,
829
00:50:02,033 --> 00:50:06,035
the technique provides
a quick and cost-effective way
830
00:50:06,037 --> 00:50:07,737
to detect pollution.
831
00:50:10,741 --> 00:50:14,110
Elsewhere, scientists
have modified firefly genes
832
00:50:14,112 --> 00:50:16,312
in the hopes of creating
bioluminescent trees
833
00:50:16,314 --> 00:50:21,217
that could one day
light up cities.
834
00:50:21,219 --> 00:50:24,453
Another lab has co-opted
marine bacteria
835
00:50:24,455 --> 00:50:27,123
to produce
an electricity-free lamp.
836
00:50:29,726 --> 00:50:32,595
And it might not be
a cure for cancer
837
00:50:32,597 --> 00:50:34,697
or a map of the brain,
838
00:50:34,699 --> 00:50:38,267
but one company has made
biofluorescence available
839
00:50:38,269 --> 00:50:39,735
to the masses,
840
00:50:39,737 --> 00:50:43,105
with green fluorescent
ice cream,
841
00:50:43,107 --> 00:50:45,408
a mere $220 or so per scoop.
842
00:50:52,816 --> 00:50:54,750
As for Vincent, David, and John,
843
00:50:54,752 --> 00:50:57,319
they're already planning
a return trip
844
00:50:57,321 --> 00:50:59,188
to the South Pacific
845
00:50:59,190 --> 00:51:02,391
and other remote stretches
of our planet
846
00:51:02,393 --> 00:51:06,562
to search for new
dazzling critters,
847
00:51:06,564 --> 00:51:10,266
both bioluminescent
and biofluorescent.
848
00:51:14,171 --> 00:51:17,273
GRUBER: We humans can't
create these from scratch.
849
00:51:17,275 --> 00:51:18,808
We need to go to the corals,
850
00:51:18,810 --> 00:51:22,578
we need to go to these fishes
to find these molecules
851
00:51:22,580 --> 00:51:26,348
that we can then illuminate
the inner workings of ourself.
852
00:51:26,350 --> 00:51:29,018
To me, I think that's just,
you know, incredibly cool.
853
00:51:30,620 --> 00:51:33,055
NARRATOR: We're only just
beginning to see the light
854
00:51:33,057 --> 00:51:36,225
of this mysterious hidden world.
855
00:51:38,662 --> 00:51:42,598
Who knows what illuminating
wonders await?
856
00:51:44,167 --> 00:51:46,735
But thanks to those alluring
creatures of light,
857
00:51:46,737 --> 00:51:52,074
the future of at least
one species, our own,
858
00:51:52,076 --> 00:51:55,311
may be an enlightened one.
859
00:52:23,306 --> 00:52:26,008
This NOVA program is available on DVD.
The investigation continues online,
860
00:52:26,010 --> 00:52:31,447
To order, visit shopPBS.org
or call 1-800-PLAY-PBS.
861
00:52:31,449 --> 00:52:34,016
NOVA is also available
for download on iTunes.
862
00:52:55,672 --> 00:52:58,641
Captioned by Media Access
Group at WGBH access.wgbh.org