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PROFESSOR: OK, I hope you all
got the message I just sent.

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00:00:25,350 --> 00:00:29,310
I finally found the
meerkat videos on YouTube.

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00:00:29,310 --> 00:00:35,010
They weren't coming up in the
searches, especially Part Two.

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00:00:35,010 --> 00:00:37,930
But once you realize
they're on YouTube,

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00:00:37,930 --> 00:00:40,490
they're easier to find,
and I posted the links

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00:00:40,490 --> 00:00:42,570
to both of them.

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00:00:42,570 --> 00:00:45,770
So if you missed that last
time, you can watch it

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00:00:45,770 --> 00:00:46,950
or you can watch it again.

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00:00:55,520 --> 00:01:00,990
We were talking about
communication involved

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00:01:00,990 --> 00:01:06,000
in sexual selection, and I
just wanted to point out here

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00:01:06,000 --> 00:01:09,960
that it's led to a sexual
dimorphism in some species

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00:01:09,960 --> 00:01:17,440
that's so extreme-- like in
these little Anolis lizards--

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00:01:17,440 --> 00:01:22,690
that the differences are
greater between male and female

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00:01:22,690 --> 00:01:26,080
than they are between some
of the species in that genus.

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00:01:29,470 --> 00:01:34,290
So it's a major factor
affecting evolution,

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00:01:34,290 --> 00:01:38,800
and we should get a chance
at the end of the class

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00:01:38,800 --> 00:01:41,615
to show some are
examples of that.

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00:01:45,650 --> 00:01:48,000
But let's deal with some
other questions first.

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00:01:48,000 --> 00:01:52,600
One is, the evolution of
ritualized fighting behavior.

27
00:01:52,600 --> 00:01:57,350
Why do so many species engage
in ritual fighting, instead of

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00:01:57,350 --> 00:01:59,960
real fighting, in
order to, for example,

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00:01:59,960 --> 00:02:03,335
decide on relative
dominance of the males?

30
00:02:08,350 --> 00:02:10,370
This has been studied by Scott.

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00:02:10,370 --> 00:02:13,680
He's done specific
studies of the blue tits,

32
00:02:13,680 --> 00:02:19,660
and he has a discussion
that's particularly

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00:02:19,660 --> 00:02:25,705
telling of these beautiful
birds called the lorikeets.

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00:02:25,705 --> 00:02:29,430
A guy named James
Serpell did the studies.

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00:02:29,430 --> 00:02:31,310
These are what they look like.

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00:02:31,310 --> 00:02:34,960
This is a small one.

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00:02:34,960 --> 00:02:39,190
Here's another small one,
and here's a very large one.

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00:02:39,190 --> 00:02:42,980
And note the enormous
beak on this one.

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00:02:42,980 --> 00:02:48,910
Well, when Serpell looked
at the fighting behavior

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00:02:48,910 --> 00:02:52,740
of these various
types of lorikeets,

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00:02:52,740 --> 00:02:56,900
he found that the large
ones, like this one,

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00:02:56,900 --> 00:03:00,340
engage in the most
ritualized fighting,

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00:03:00,340 --> 00:03:02,180
whereas the small
ones were much more

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00:03:02,180 --> 00:03:08,150
likely to engage in real fights.

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00:03:08,150 --> 00:03:12,440
There's an obvious reason.

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00:03:12,440 --> 00:03:16,810
The big ones are capable
of doing a lot more damage,

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00:03:16,810 --> 00:03:21,305
so the individual, his chance
of getting injured in a fight,

48
00:03:21,305 --> 00:03:23,260
are much greater.

49
00:03:23,260 --> 00:03:26,710
These little birds aren't as
capable of hurting each other.

50
00:03:26,710 --> 00:03:34,085
So that's why it appears that
the bigger birds have engaged

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00:03:34,085 --> 00:03:35,570
in more ritualized fighting.

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00:03:39,080 --> 00:03:44,320
Later we'll get a chance to see
some studies of domestic cats,

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00:03:44,320 --> 00:03:50,110
and you will see the ritualized
way that male cats often

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00:03:50,110 --> 00:03:51,300
settle their differences.

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00:03:51,300 --> 00:03:52,240
They don't always.

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00:03:52,240 --> 00:03:55,840
Sometimes they really
fight, and they can badly

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00:03:55,840 --> 00:03:57,410
damage each other.

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00:03:57,410 --> 00:04:02,230
But usually, it's
done by ritual.

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00:04:02,230 --> 00:04:03,630
And also, they remember.

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00:04:03,630 --> 00:04:05,050
So if they did
have a real fight,

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00:04:05,050 --> 00:04:09,220
it will usually only be
one with the same animal.

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00:04:09,220 --> 00:04:12,180
They will remember the
outcome, and everything else

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00:04:12,180 --> 00:04:13,770
is settled by this posturing.

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00:04:16,940 --> 00:04:19,820
Let's talk about a few other
forms of communication ,

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00:04:19,820 --> 00:04:22,200
like auditory communication.

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00:04:22,200 --> 00:04:26,820
So what's the big advantage
of auditory communication

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00:04:26,820 --> 00:04:31,390
in animals like whales,
songbirds, marmoset monkeys.

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00:04:31,390 --> 00:04:33,840
What do those such
disparate animals

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00:04:33,840 --> 00:04:36,630
have in common,
whales, songbirds,

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00:04:36,630 --> 00:04:39,460
and marmoset monkeys?

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00:04:39,460 --> 00:04:42,220
They all engage in a lot
of auditory communication.

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00:04:45,970 --> 00:04:50,100
Think of the difficulty
of visual communication.

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00:04:50,100 --> 00:04:52,470
Whales, because
they live in water,

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00:04:52,470 --> 00:04:56,200
how far can they
see in the ocean?

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00:04:56,200 --> 00:04:59,850
And they're swimming large
distances from each other.

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00:04:59,850 --> 00:05:02,340
Auditory communication
works very well

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00:05:02,340 --> 00:05:05,140
over very long
distances, and they

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00:05:05,140 --> 00:05:07,310
say the effective
range of whale calls

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00:05:07,310 --> 00:05:11,290
is they think more
than 100 kilometers.

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It seems hard to believe.

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00:05:14,080 --> 00:05:16,270
For songbirds, of course
they live in forests,

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00:05:16,270 --> 00:05:18,550
there's so much
foliage, they have

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00:05:18,550 --> 00:05:20,230
difficulty seeing each other.

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00:05:20,230 --> 00:05:23,580
Not for real close
range, of course,

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00:05:23,580 --> 00:05:25,560
like you would find
in courtship behavior,

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00:05:25,560 --> 00:05:28,940
but other kinds
of communication,

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00:05:28,940 --> 00:05:36,010
like response to alarm calls.

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00:05:36,010 --> 00:05:37,770
They're often far
apart, and they're not

89
00:05:37,770 --> 00:05:40,210
going to be able
to see each other.

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00:05:40,210 --> 00:05:42,090
Marmoset monkeys, similar.

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00:05:42,090 --> 00:05:43,880
Dense foliage.

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00:05:43,880 --> 00:05:48,060
They need their calls,
auditory communication,

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00:05:48,060 --> 00:05:50,520
just to be in touch
with each other.

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00:05:53,610 --> 00:06:01,070
So I'm asking for distinct
functions of birdsong.

95
00:06:01,070 --> 00:06:04,140
This is part of that, of
course, very important

96
00:06:04,140 --> 00:06:07,850
in auditory
communication in birds.

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00:06:07,850 --> 00:06:11,280
What are the different kinds
of functions of birdsong?

98
00:06:11,280 --> 00:06:12,110
Why do they sing?

99
00:06:16,520 --> 00:06:18,691
can anybody suggest even one?

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00:06:18,691 --> 00:06:19,190
Yes.

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00:06:19,190 --> 00:06:20,999
AUDIENCE: Mating.

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00:06:20,999 --> 00:06:22,790
PROFESSOR: How would
it function in mating?

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00:06:22,790 --> 00:06:26,290
AUDIENCE: If you could say
you're ready for a mate,

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00:06:26,290 --> 00:06:29,710
and trying to give off
a more verbose call.

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00:06:29,710 --> 00:06:31,210
PROFESSOR: Could be advertising.

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00:06:31,210 --> 00:06:32,000
OK.

107
00:06:32,000 --> 00:06:34,660
So advertising is important.

108
00:06:34,660 --> 00:06:36,690
Not only that, they
want to advertise

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00:06:36,690 --> 00:06:40,560
more than just the fact
they're ready to mate.

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00:06:40,560 --> 00:06:42,190
"I'm a male and
I'm ready to mate."

111
00:06:42,190 --> 00:06:42,690
No.

112
00:06:42,690 --> 00:06:45,481
They want to be, "I'm
a really fit male,

113
00:06:45,481 --> 00:06:47,730
and you should mate with me
rather than that other guy

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00:06:47,730 --> 00:06:49,710
over there, because
my song is better.

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00:06:52,675 --> 00:06:56,310
I have a larger
repertoire," and so forth.

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00:06:56,310 --> 00:06:59,750
So these are males
attracting females

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00:06:59,750 --> 00:07:02,240
I have put as number one here.

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00:07:02,240 --> 00:07:04,620
The second would be
females judging males

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00:07:04,620 --> 00:07:06,175
for purposes of mate selection.

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00:07:08,940 --> 00:07:11,310
Another is territorial
advertisement.

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00:07:11,310 --> 00:07:14,930
This it has to do with
male-male interactions.

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00:07:14,930 --> 00:07:19,410
They occupy distinct areas
where they establish their nest

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00:07:19,410 --> 00:07:25,110
in the center of the area
where they're foraging.

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00:07:25,110 --> 00:07:28,320
They each have a home range.

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00:07:28,320 --> 00:07:30,840
And many animals do
this, they establish

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00:07:30,840 --> 00:07:32,840
very clear territories.

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00:07:32,840 --> 00:07:36,290
Many hunting animals have
distinct territories.

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00:07:36,290 --> 00:07:38,340
In some of them,
they're overlapping,

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00:07:38,340 --> 00:07:41,630
in some of them they are not.

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00:07:41,630 --> 00:07:46,690
But in birds, birdsong plays
a very important role in that.

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00:07:50,510 --> 00:07:53,500
The other that many
people are not aware of,

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00:07:53,500 --> 00:08:00,100
is in some species it's part of
pair bonding, where they sing.

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00:08:00,100 --> 00:08:02,510
And what sounds
like a single song--

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00:08:02,510 --> 00:08:04,440
and you'll hear their
singing in the forest,

135
00:08:04,440 --> 00:08:06,150
and you'll swear
it's only one bird

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00:08:06,150 --> 00:08:09,850
singing when it's actually
two-- it's a duet.

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00:08:09,850 --> 00:08:11,240
And they recorded these.

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00:08:11,240 --> 00:08:16,820
It was the British
ethologist and ornithologist

139
00:08:16,820 --> 00:08:20,930
Thorpe who first described
it, and recordings

140
00:08:20,930 --> 00:08:23,640
were made by him
and his students,

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00:08:23,640 --> 00:08:27,750
where they were able to separate
the songs, the contributions

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00:08:27,750 --> 00:08:29,060
of the male and female.

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00:08:29,060 --> 00:08:32,740
And they're perfectly--
they interleave

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00:08:32,740 --> 00:08:35,840
their notes and
phrases of the song.

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00:08:35,840 --> 00:08:39,815
So this duet is a major
part of their bonding.

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00:08:43,080 --> 00:08:45,050
And you can find some
interesting things

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00:08:45,050 --> 00:08:46,090
online about that.

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00:08:46,090 --> 00:08:48,160
I've noted one of them here.

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00:08:48,160 --> 00:08:52,310
But if you do a search on
that, duets in birdsong,

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00:08:52,310 --> 00:08:56,670
you will find pretty
interesting studies.

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00:08:56,670 --> 00:09:00,710
Now I mentioned here
one that we don't

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have direct experience
of it all: communication

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00:09:03,560 --> 00:09:06,700
by electrical signals.

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00:09:06,700 --> 00:09:10,380
So when would that
really be important?

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00:09:10,380 --> 00:09:13,350
It's done in animals
living in water.

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00:09:16,680 --> 00:09:21,080
And water, where
visual communication

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00:09:21,080 --> 00:09:28,290
is difficult, but rather
than using auditory,

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00:09:28,290 --> 00:09:32,960
a number of fish species use
electrical communication,

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00:09:32,960 --> 00:09:37,560
and they use it for
other means, too.

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00:09:37,560 --> 00:09:41,010
Especially these two
groups: the mormyrid

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00:09:41,010 --> 00:09:43,450
in Africa and the South
American gymnotids.

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00:09:47,460 --> 00:09:50,710
And they have
corresponding development

163
00:09:50,710 --> 00:09:55,660
of specialized
receptors, specialized

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00:09:55,660 --> 00:09:58,820
secondary sensory neuron
groups in the brain,

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00:09:58,820 --> 00:10:02,000
and specialized
regions for analyzing

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00:10:02,000 --> 00:10:03,250
that electrical information.

167
00:10:06,240 --> 00:10:08,940
So they're in murky waters,
and they have these receptors

168
00:10:08,940 --> 00:10:15,400
all along the lateral line
along the side of their body.

169
00:10:15,400 --> 00:10:18,460
It's innervated by
cranial nerves that

170
00:10:18,460 --> 00:10:20,680
are not found in mammals at all.

171
00:10:23,540 --> 00:10:25,850
We always say we have
12 cranial nerves,

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00:10:25,850 --> 00:10:28,900
but those are sort
of the standard way

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00:10:28,900 --> 00:10:30,470
of enumerating them.

174
00:10:30,470 --> 00:10:34,160
If you look throughout
vertebrate species

175
00:10:34,160 --> 00:10:38,170
there's at least
25 cranial nerves,

176
00:10:38,170 --> 00:10:44,500
and six of those in some
fish are cranial nerves

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00:10:44,500 --> 00:10:48,285
devoted to
electrosensory functions.

178
00:10:51,900 --> 00:10:57,150
So these are pictures of
a couple of mormyrid fish,

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00:10:57,150 --> 00:11:01,120
and recordings of the
electrical pulses they emit.

180
00:11:01,120 --> 00:11:05,520
So they're not just
responding to electrical pulse

181
00:11:05,520 --> 00:11:06,680
or detecting it.

182
00:11:06,680 --> 00:11:09,420
They also emit
electrical pulses.

183
00:11:09,420 --> 00:11:11,540
Now, a few of them,
like some electric eels,

184
00:11:11,540 --> 00:11:16,860
are capable of producing such
a strong electrical pulse

185
00:11:16,860 --> 00:11:20,460
in the water that they can
actually based on smaller prey

186
00:11:20,460 --> 00:11:23,480
animals, and so they
use it in prey catching.

187
00:11:23,480 --> 00:11:26,520
But these animals aren't
using it for that.

188
00:11:26,520 --> 00:11:31,410
This is a form of communication
and of sensory detection.

189
00:11:31,410 --> 00:11:35,720
So in this diagram,
you see field lines

190
00:11:35,720 --> 00:11:40,010
of an electric field generated
around these animals.

191
00:11:40,010 --> 00:11:45,840
They usually have electric
generator area cells

192
00:11:45,840 --> 00:11:47,620
towards the tail region.

193
00:11:47,620 --> 00:11:50,500
They generate this
field around their body,

194
00:11:50,500 --> 00:11:55,560
and their lateral line receptors
all along the side of the body

195
00:11:55,560 --> 00:11:58,750
respond to that field.

196
00:11:58,750 --> 00:12:02,310
And any animal that enters
the field distorts it,

197
00:12:02,310 --> 00:12:08,440
and they detect that distortion,
and they compute exactly where

198
00:12:08,440 --> 00:12:11,021
the disturbance
was in the field.

199
00:12:11,021 --> 00:12:12,020
They're very good at it.

200
00:12:12,020 --> 00:12:15,440
It's a very good means
of communication.

201
00:12:15,440 --> 00:12:18,680
So they have
specialized emitters

202
00:12:18,680 --> 00:12:20,200
emitting the electrical pulses.

203
00:12:20,200 --> 00:12:23,370
They have specialized receptors
along the side of their body

204
00:12:23,370 --> 00:12:26,870
that all come-- governed
by hindbrain mechanisms,

205
00:12:26,870 --> 00:12:30,240
as I've indicated here.

206
00:12:30,240 --> 00:12:32,530
Now there's other
sensory means, too.

207
00:12:32,530 --> 00:12:37,120
One that you're probably more
familiar with is the catfish.

208
00:12:37,120 --> 00:12:39,800
They have very
specialized taste systems.

209
00:12:39,800 --> 00:12:44,060
This is a picture, it's
actually from my 914 class,

210
00:12:44,060 --> 00:12:50,640
it shows a drawing of a catfish.

211
00:12:50,640 --> 00:12:52,970
Bullheads are
examples of catfish.

212
00:12:52,970 --> 00:12:56,420
This is not a Bullhead,
but it's similar.

213
00:12:56,420 --> 00:12:59,760
And what they're showing here is
one cranial nerve, the seventh,

214
00:12:59,760 --> 00:13:02,250
which is the facial nerve.

215
00:13:02,250 --> 00:13:03,660
But look at it in this animal.

216
00:13:03,660 --> 00:13:07,720
It innervates the
entire body surface,

217
00:13:07,720 --> 00:13:12,550
and it innervates
these little barblets.

218
00:13:12,550 --> 00:13:14,670
What are they doing with those?

219
00:13:14,670 --> 00:13:16,630
Well, it's important
in their feeding.

220
00:13:16,630 --> 00:13:20,910
Remember, they live
in very muddy water.

221
00:13:20,910 --> 00:13:23,330
They literally go
along the bottom,

222
00:13:23,330 --> 00:13:27,000
dragging these things along
the water, and tasting

223
00:13:27,000 --> 00:13:31,400
what's there, so that can
detect when they're near food.

224
00:13:36,250 --> 00:13:38,560
And I point out here that
this catfish that you

225
00:13:38,560 --> 00:13:44,560
see in the picture and
the other catfish, too,

226
00:13:44,560 --> 00:13:47,300
they've developed
specialized cell

227
00:13:47,300 --> 00:13:50,260
groups that respond
to that input.

228
00:13:50,260 --> 00:13:54,480
So, the seventh nerve
nuclei in the hindbrain

229
00:13:54,480 --> 00:13:55,980
develop very large size.

230
00:13:55,980 --> 00:14:01,900
So much that these animals,
the side of their hindbrain

231
00:14:01,900 --> 00:14:04,510
bulges out in that region.

232
00:14:04,510 --> 00:14:06,660
There's one fish,
the buffalo fish,

233
00:14:06,660 --> 00:14:12,130
that it's not just the seventh
cranial nerve, but the ninth

234
00:14:12,130 --> 00:14:15,950
and tenth that
innervates the throat.

235
00:14:15,950 --> 00:14:18,885
And the reason is, they have
specialized taste receptors.

236
00:14:21,910 --> 00:14:27,100
It's a specialized palatal
organ that, again, most animals

237
00:14:27,100 --> 00:14:28,200
don't have.

238
00:14:28,200 --> 00:14:35,350
But they filter water, passing
through their mouths and out

239
00:14:35,350 --> 00:14:39,190
their gills, they pass
it over this region .

240
00:14:39,190 --> 00:14:43,410
Again, it's used in detecting
tiny particles of food.

241
00:14:43,410 --> 00:14:45,450
And many of them have
a motor side, too,

242
00:14:45,450 --> 00:14:47,335
that will trap the particles.

243
00:14:50,430 --> 00:14:53,120
It's a particular
way of feeding.

244
00:14:53,120 --> 00:14:56,080
And of course, these
animals, all of them

245
00:14:56,080 --> 00:14:59,270
have specialized
fixed action patterns,

246
00:14:59,270 --> 00:15:01,220
part of their
foraging and feeding

247
00:15:01,220 --> 00:15:05,380
that have developed centered
around these specialized

248
00:15:05,380 --> 00:15:06,750
sensory abilities.

249
00:15:06,750 --> 00:15:08,506
Either taste or, of
course in the case

250
00:15:08,506 --> 00:15:17,615
of the electric organs, the
gymnotids and these fish

251
00:15:17,615 --> 00:15:20,940
that we just looked at here,
mormyrids and gymnotids.

252
00:15:24,310 --> 00:15:27,030
Now what about olfaction?

253
00:15:27,030 --> 00:15:29,510
What are the advantages
and disadvantages

254
00:15:29,510 --> 00:15:30,950
of olfactory communication?

255
00:15:30,950 --> 00:15:34,320
This is a particularly
interesting one for mammals,

256
00:15:34,320 --> 00:15:38,540
because it appears to be
of such major importance

257
00:15:38,540 --> 00:15:41,880
in the early
mammalian evolution.

258
00:15:46,480 --> 00:15:49,740
We've detected
fossils of mammals

259
00:15:49,740 --> 00:15:54,020
from the time of
the early dinosaurs.

260
00:15:54,020 --> 00:15:59,340
They were apparently nocturnal
animals living on the forest

261
00:15:59,340 --> 00:16:01,750
floor, and they
had a big problem.

262
00:16:01,750 --> 00:16:04,810
How do you avoid these
very visual predators

263
00:16:04,810 --> 00:16:05,690
roaming the earth?

264
00:16:05,690 --> 00:16:10,430
At that time, the dominant
species were the lizards.

265
00:16:10,430 --> 00:16:13,750
And they developed specialized
olfactory abilities.

266
00:16:13,750 --> 00:16:16,325
It functions in
complete darkness.

267
00:16:16,325 --> 00:16:19,300
It functions as
a distance sense.

268
00:16:19,300 --> 00:16:21,810
They don't have to be
sniffing something right

269
00:16:21,810 --> 00:16:22,740
under their noses.

270
00:16:22,740 --> 00:16:26,250
They can detect through the air.

271
00:16:26,250 --> 00:16:27,790
Some of the scents linger.

272
00:16:27,790 --> 00:16:31,290
It varies, but many of
them linger for some time,

273
00:16:31,290 --> 00:16:34,070
so it gives some
information about things

274
00:16:34,070 --> 00:16:35,565
that happened in
the recent past.

275
00:16:38,330 --> 00:16:41,760
When your dog enters a
room, he doesn't just

276
00:16:41,760 --> 00:16:43,030
smell food in the room.

277
00:16:43,030 --> 00:16:45,190
He smells who was
there recently,

278
00:16:45,190 --> 00:16:48,840
and who's there now, who
was there minutes ago,

279
00:16:48,840 --> 00:16:50,780
who was there 10 minutes ago?

280
00:16:50,780 --> 00:16:53,360
Because the odors linger.

281
00:16:53,360 --> 00:16:57,370
This is something animals can
do with olfaction that they

282
00:16:57,370 --> 00:16:58,740
can't do with the other senses.

283
00:17:02,620 --> 00:17:06,180
Also, there's evidence that
in these very early mammals,

284
00:17:06,180 --> 00:17:09,680
they evolved out of a group
called mammal-like reptiles.

285
00:17:09,680 --> 00:17:15,010
And there was a regression,
according to the skull evidence

286
00:17:15,010 --> 00:17:19,839
that we have, of regression
of the visual sense,

287
00:17:19,839 --> 00:17:25,829
reduced bones around
the eye, and so forth.

288
00:17:25,829 --> 00:17:29,780
And we should, of course, add
that the audition developed

289
00:17:29,780 --> 00:17:32,320
in a special way,
too, in the mammals.

290
00:17:32,320 --> 00:17:38,010
Mammals evolved
specialized little bones.

291
00:17:38,010 --> 00:17:39,190
Formed the middle ear.

292
00:17:39,190 --> 00:17:41,890
There was only one
bone in the reptiles,

293
00:17:41,890 --> 00:17:44,620
equivalent to the stapes,
but the other small bones

294
00:17:44,620 --> 00:17:45,120
developed.

295
00:17:45,120 --> 00:17:48,950
That was very important, because
it allowed impedance matching

296
00:17:48,950 --> 00:17:53,760
between air pressure
level changes in the air,

297
00:17:53,760 --> 00:17:56,750
and in the fluids
of the inner ear.

298
00:17:56,750 --> 00:17:59,405
And that evolution was also
very important in mammals.

299
00:18:03,380 --> 00:18:06,070
Back to auditory .

300
00:18:06,070 --> 00:18:07,380
Alarm calls.

301
00:18:07,380 --> 00:18:10,200
I'm asking about two
functions of alarm calls.

302
00:18:10,200 --> 00:18:13,510
One's obvious, the
other's not so obvious.

303
00:18:13,510 --> 00:18:17,660
Well, the first one, of course,
is warning other animals

304
00:18:17,660 --> 00:18:20,400
of the same species of danger.

305
00:18:20,400 --> 00:18:22,400
That's important
for an individual,

306
00:18:22,400 --> 00:18:25,290
because if he can do it, other
animals in the group can do it.

307
00:18:25,290 --> 00:18:29,930
So if they all do it,
they're all benefiting.

308
00:18:29,930 --> 00:18:34,560
But the second function is
that it signals the predator.

309
00:18:34,560 --> 00:18:37,380
"You've been detected,
and we're watching you.

310
00:18:37,380 --> 00:18:40,080
It's useless for you to
continue trying to catch us,

311
00:18:40,080 --> 00:18:42,510
because we run very fast
and we can already see you.

312
00:18:42,510 --> 00:18:45,510
You'll never catch us."

313
00:18:45,510 --> 00:18:47,610
So animals actually
go out of their way

314
00:18:47,610 --> 00:18:49,315
to display to predators.

315
00:18:52,310 --> 00:18:58,920
Remember the mobbing response in
the geese and in the jackdaws?

316
00:18:58,920 --> 00:19:05,020
We saw it in the
video of the geese.

317
00:19:05,020 --> 00:19:08,170
They're not just responding
to predators by running away.

318
00:19:08,170 --> 00:19:11,020
They form in a group
and they mob them.

319
00:19:17,060 --> 00:19:23,460
Why do foraging birds sometimes
emit at a fake alarm call?

320
00:19:23,460 --> 00:19:25,780
Why would they do it?

321
00:19:25,780 --> 00:19:27,840
Well, maybe because
they see food

322
00:19:27,840 --> 00:19:30,980
and they want to get
rid of the competition.

323
00:19:30,980 --> 00:19:35,000
So they can get the other
animals to run away, then they

324
00:19:35,000 --> 00:19:36,650
can get the food.

325
00:19:36,650 --> 00:19:40,810
The problem is, these
animals remember.

326
00:19:40,810 --> 00:19:45,990
And if he emits fake alarm
calls a couple of times,

327
00:19:45,990 --> 00:19:51,030
the other birds learn
who it is doing that,

328
00:19:51,030 --> 00:19:55,010
and they learn that those
calls are unreliable.

329
00:19:55,010 --> 00:20:01,310
So individual recognition by
their cognitive abilities,

330
00:20:01,310 --> 00:20:04,060
very important.

331
00:20:04,060 --> 00:20:06,760
So if too many animals
did that, of course,

332
00:20:06,760 --> 00:20:09,410
the alarm calls would
lose their usefulness.

333
00:20:09,410 --> 00:20:13,000
But it doesn't
function very long,

334
00:20:13,000 --> 00:20:16,220
so in fact, it doesn't
happen often enough

335
00:20:16,220 --> 00:20:21,200
to lead to a loss of
alarm calls in evolution.

336
00:20:21,200 --> 00:20:25,590
Now, of course, many other
animals besides birds do this.

337
00:20:25,590 --> 00:20:31,080
I'm asking here about ground
squirrels and vervet monkeys.

338
00:20:31,080 --> 00:20:35,310
They convey specific
information about predators

339
00:20:35,310 --> 00:20:38,740
when they give alarm calls,
and this is my summary of that.

340
00:20:38,740 --> 00:20:43,880
The ground squirrels respond
to threats from the air

341
00:20:43,880 --> 00:20:47,520
or from terrestrial predators.

342
00:20:47,520 --> 00:20:53,240
The ones from the air, from
raptors, mean very high risk.

343
00:20:53,240 --> 00:20:55,680
They can be much more
easily caught by a raptor

344
00:20:55,680 --> 00:20:57,760
than they can by
a ground predator.

345
00:20:57,760 --> 00:21:02,300
So they emit these
short, shrill whistles.

346
00:21:02,300 --> 00:21:05,080
If it's lower risk,
a ground predator,

347
00:21:05,080 --> 00:21:09,710
they have a trill and a chatter,
which always indicates threat

348
00:21:09,710 --> 00:21:10,650
from ground predators.

349
00:21:10,650 --> 00:21:13,790
So the other members
of their species

350
00:21:13,790 --> 00:21:16,350
can tell what kind of
predator they should watch out

351
00:21:16,350 --> 00:21:18,900
for when an animal
emits these calls.

352
00:21:18,900 --> 00:21:21,970
In vervet monkeys, it's
even a little more complex.

353
00:21:21,970 --> 00:21:23,560
[INAUDIBLE] threats
from the air,

354
00:21:23,560 --> 00:21:26,070
they make a coughing noise.

355
00:21:26,070 --> 00:21:30,090
If it's a leopard,
they emit a bark.

356
00:21:30,090 --> 00:21:33,380
And for snakes, they
make a chattering noise.

357
00:21:33,380 --> 00:21:37,460
So it's very easy to tell
which kind of predator

358
00:21:37,460 --> 00:21:38,770
they should watch out for.

359
00:21:38,770 --> 00:21:42,820
And that information is very
important for these animals

360
00:21:42,820 --> 00:21:44,410
in avoiding those predators .

361
00:21:47,320 --> 00:21:52,070
And, of course, they learn
that some animals more

362
00:21:52,070 --> 00:21:53,930
reliable than others,
not just because they

363
00:21:53,930 --> 00:21:57,790
emit fake alarm calls,
but they sometimes

364
00:21:57,790 --> 00:22:02,680
jump the gun too quickly, they
emit alarm calls too often.

365
00:22:02,680 --> 00:22:05,030
And also, they
discriminate young and old.

366
00:22:05,030 --> 00:22:09,500
They learn that young
animals are less reliable.

367
00:22:09,500 --> 00:22:16,010
They're likely to start
chattering alarm calls when

368
00:22:16,010 --> 00:22:18,860
there's no real threat
from the predator.

369
00:22:18,860 --> 00:22:20,900
It doesn't mean they
didn't detect one,

370
00:22:20,900 --> 00:22:23,400
but he may be too far away
to be emitting an alarm call.

371
00:22:23,400 --> 00:22:28,682
So they depend mostly
on the older animals

372
00:22:28,682 --> 00:22:29,640
that are more reliable.

373
00:22:33,860 --> 00:22:35,580
So we just talked
about a function

374
00:22:35,580 --> 00:22:38,740
of individual recognition.

375
00:22:38,740 --> 00:22:41,260
What other functions of
individual recognition

376
00:22:41,260 --> 00:22:44,000
are there, besides
this, remembering

377
00:22:44,000 --> 00:22:47,340
about reliability
of alarm calls?

378
00:22:52,670 --> 00:22:57,340
An animal can remember previous
encounters with the individual.

379
00:22:57,340 --> 00:23:00,210
I mentioned that when we talked
about ritualized fighting

380
00:23:00,210 --> 00:23:01,480
and real fighting.

381
00:23:01,480 --> 00:23:04,810
It's very important that they
remember the results of fights,

382
00:23:04,810 --> 00:23:10,945
because it saves a lot of
injury and energy later.

383
00:23:14,350 --> 00:23:18,290
So just to remember their place
in the hierarchy of animals

384
00:23:18,290 --> 00:23:23,245
in their species, individual
recognition's very important.

385
00:23:23,245 --> 00:23:24,970
What other functions are there?

386
00:23:24,970 --> 00:23:30,710
Well, they can recognize
members of their closely related

387
00:23:30,710 --> 00:23:34,196
animals, their young,
their mate, so forth.

388
00:23:39,920 --> 00:23:42,850
Did you know that there's
other species besides humans

389
00:23:42,850 --> 00:23:47,560
that have names for
other individuals?

390
00:23:47,560 --> 00:23:51,202
One we know about the
most is the dolphin.

391
00:23:51,202 --> 00:23:53,035
They have what's called
a signature whistle.

392
00:23:55,980 --> 00:23:58,930
The data on other species
is not as reliable,

393
00:23:58,930 --> 00:24:02,640
but we know the
elephants, for example,

394
00:24:02,640 --> 00:24:05,420
seem to be able to
convey something

395
00:24:05,420 --> 00:24:08,130
specific to an individual.

396
00:24:08,130 --> 00:24:12,360
We know less about the
language they're using.

397
00:24:12,360 --> 00:24:17,250
It's been studied a little
more intensively in dolphins.

398
00:24:17,250 --> 00:24:21,160
This is an area that a lot
more study could be done.

399
00:24:21,160 --> 00:24:28,150
Now, there's two videos
that I would like to see.

400
00:24:28,150 --> 00:24:30,310
I'm not going to show
this one initially,

401
00:24:30,310 --> 00:24:34,940
because it's available
easily online.

402
00:24:34,940 --> 00:24:37,190
And I've asked some
questions about it,

403
00:24:37,190 --> 00:24:40,120
and it only lasts
about 10 minutes.

404
00:24:40,120 --> 00:24:41,415
It's very easy to get online.

405
00:24:45,900 --> 00:24:48,190
We can watch part
of it if you want,

406
00:24:48,190 --> 00:24:57,240
but I have video clips
illustrating sexual selection.

407
00:24:57,240 --> 00:25:00,450
It's from another
nature program ,

408
00:25:00,450 --> 00:25:04,240
called What Females
Want and Males Will Do,

409
00:25:04,240 --> 00:25:05,370
and it's quite fascinating.

410
00:25:07,970 --> 00:25:10,720
If I can get these
in control of it.

411
00:25:10,720 --> 00:25:14,400
When I started today
I couldn't, but I

412
00:25:14,400 --> 00:25:17,225
think I figured out what
I was doing on wrong.

413
00:25:37,050 --> 00:25:39,400
The only player I can
get to do this right

414
00:25:39,400 --> 00:25:43,250
is WinDVD, because then I
can go to go to the parts

415
00:25:43,250 --> 00:25:44,360
that I'm interested in.

416
00:25:57,690 --> 00:25:59,600
All the same birds,
emitting all of it.

417
00:26:03,600 --> 00:26:07,510
This content has been removed
due to copyright restrictions.

418
00:26:07,510 --> 00:26:09,430
See the readings
and viewings page

419
00:26:09,430 --> 00:26:11,240
for information
about this material.

420
00:26:16,450 --> 00:26:17,910
PROFESSOR: All of
that has evolved

421
00:26:17,910 --> 00:26:20,350
because of sexual selection.

422
00:26:20,350 --> 00:26:22,230
You see the gradual
changes that you

423
00:26:22,230 --> 00:26:24,290
can trace closely
related species,

424
00:26:24,290 --> 00:26:26,370
and you see all
kinds of variations

425
00:26:26,370 --> 00:26:29,050
of these elaborate
calls and dances.

426
00:26:29,050 --> 00:26:32,810
You find it throughout nature.

427
00:26:32,810 --> 00:26:34,650
And, of course, I
pointed out last time

428
00:26:34,650 --> 00:26:38,480
that humans have developed
various ways, of course,

429
00:26:38,480 --> 00:26:42,570
some of which are instinctive,
but a lot of these

430
00:26:42,570 --> 00:26:43,930
are modified by learning.

431
00:26:43,930 --> 00:26:46,640
But most of what you saw
today was all instinctive.

432
00:26:46,640 --> 00:26:50,410
Every member of the species
does something very similar.

433
00:26:50,410 --> 00:26:52,880
But, of course, that
first one you saw,

434
00:26:52,880 --> 00:26:57,280
the animal that could
imitate the lyre bird,

435
00:26:57,280 --> 00:26:59,180
could imitate anything.

436
00:26:59,180 --> 00:27:01,340
It's an incredible
amount of learning.

437
00:27:01,340 --> 00:27:05,430
And how many different
things he could remember,

438
00:27:05,430 --> 00:27:08,150
and the elaborateness
of what he remembers,

439
00:27:08,150 --> 00:27:11,190
that's what impresses
the females.

440
00:27:11,190 --> 00:27:13,400
All right, so that's
all for today.

441
00:27:22,430 --> 00:27:26,350
So remember to watch the
horse video yourself, OK?