[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.72,0:00:02.97,Default,,0000,0000,0000,,This is poo,
Dialogue: 0,0:00:02.97,0:00:05.46,Default,,0000,0000,0000,,and what I want to do today is share my passion
Dialogue: 0,0:00:05.46,0:00:08.60,Default,,0000,0000,0000,,for poo with you,
Dialogue: 0,0:00:08.60,0:00:11.41,Default,,0000,0000,0000,,which might be quite difficult,
Dialogue: 0,0:00:11.41,0:00:14.50,Default,,0000,0000,0000,,but I think what you might find more fascinating
Dialogue: 0,0:00:14.50,0:00:17.70,Default,,0000,0000,0000,,is the way these small animals deal with poo.
Dialogue: 0,0:00:17.70,0:00:20.06,Default,,0000,0000,0000,,So this animal here has got a brain
Dialogue: 0,0:00:20.06,0:00:24.02,Default,,0000,0000,0000,,about the size of a grain of rice, and yet it can do things
Dialogue: 0,0:00:24.02,0:00:27.77,Default,,0000,0000,0000,,that you and I couldn't possibly entertain the idea of doing.
Dialogue: 0,0:00:27.77,0:00:31.89,Default,,0000,0000,0000,,And basically it's all evolved to handle its food source,
Dialogue: 0,0:00:31.89,0:00:34.02,Default,,0000,0000,0000,,which is dung.
Dialogue: 0,0:00:34.02,0:00:36.60,Default,,0000,0000,0000,,So the question is, where do we start this story?
Dialogue: 0,0:00:36.60,0:00:39.63,Default,,0000,0000,0000,,And it seems appropriate to start at the end,
Dialogue: 0,0:00:39.63,0:00:42.41,Default,,0000,0000,0000,,because this is a waste product that comes out
Dialogue: 0,0:00:42.41,0:00:45.98,Default,,0000,0000,0000,,of other animals, but it still contains nutrients
Dialogue: 0,0:00:45.98,0:00:47.94,Default,,0000,0000,0000,,and there are sufficient nutrients in there
Dialogue: 0,0:00:47.94,0:00:50.90,Default,,0000,0000,0000,,for dung beetles basically to make a living,
Dialogue: 0,0:00:50.90,0:00:53.84,Default,,0000,0000,0000,,and so dung beetles eat dung, and their larvae
Dialogue: 0,0:00:53.84,0:00:55.100,Default,,0000,0000,0000,,are also dung-feeders.
Dialogue: 0,0:00:55.100,0:00:59.22,Default,,0000,0000,0000,,They are grown completely in a ball of dung.
Dialogue: 0,0:00:59.22,0:01:03.02,Default,,0000,0000,0000,,Within South Africa, we've got about 800 species of dung beetles,
Dialogue: 0,0:01:03.02,0:01:06.29,Default,,0000,0000,0000,,in Africa we've got 2,000 species of dung beetles,
Dialogue: 0,0:01:06.29,0:01:10.89,Default,,0000,0000,0000,,and in the world we have about 6,000 species of dung beetles.
Dialogue: 0,0:01:10.89,0:01:16.03,Default,,0000,0000,0000,,So, according to dung beetles, dung is pretty good.
Dialogue: 0,0:01:16.03,0:01:18.70,Default,,0000,0000,0000,,Unless you're prepared to get dung under your fingernails
Dialogue: 0,0:01:18.70,0:01:21.47,Default,,0000,0000,0000,,and root through the dung itself, you'll never see
Dialogue: 0,0:01:21.47,0:01:23.76,Default,,0000,0000,0000,,90 percent of the dung beetle species,
Dialogue: 0,0:01:23.76,0:01:26.16,Default,,0000,0000,0000,,because they go directly into the dung,
Dialogue: 0,0:01:26.16,0:01:28.78,Default,,0000,0000,0000,,straight down below it, and then they shuttle back and forth
Dialogue: 0,0:01:28.78,0:01:30.83,Default,,0000,0000,0000,,between the dung at the soil surface
Dialogue: 0,0:01:30.83,0:01:33.77,Default,,0000,0000,0000,,and a nest they make underground.
Dialogue: 0,0:01:33.77,0:01:39.02,Default,,0000,0000,0000,,So the question is, how do they deal with this material?
Dialogue: 0,0:01:39.02,0:01:42.100,Default,,0000,0000,0000,,And most dung beetles actually wrap it into a package of some sort.
Dialogue: 0,0:01:42.100,0:01:46.68,Default,,0000,0000,0000,,Ten percent of the species actually make a ball,
Dialogue: 0,0:01:46.68,0:01:50.84,Default,,0000,0000,0000,,and this ball they roll away from the dung source,
Dialogue: 0,0:01:50.84,0:01:54.27,Default,,0000,0000,0000,,usually bury it at a remote place away from the dung source,
Dialogue: 0,0:01:54.27,0:01:57.58,Default,,0000,0000,0000,,and they have a very particular behavior
Dialogue: 0,0:01:57.58,0:02:02.55,Default,,0000,0000,0000,,by which they are able to roll their balls.
Dialogue: 0,0:02:02.55,0:02:06.15,Default,,0000,0000,0000,,So this is a very proud owner of a beautiful dung ball.
Dialogue: 0,0:02:06.15,0:02:07.38,Default,,0000,0000,0000,,You can see it's a male
Dialogue: 0,0:02:07.38,0:02:09.62,Default,,0000,0000,0000,,because he's got a little hair on the back of his legs there,
Dialogue: 0,0:02:09.62,0:02:14.69,Default,,0000,0000,0000,,and he's clearly very pleased about what he's sitting on there.
Dialogue: 0,0:02:14.69,0:02:16.60,Default,,0000,0000,0000,,And then he's about to become a victim
Dialogue: 0,0:02:16.60,0:02:21.85,Default,,0000,0000,0000,,of a vicious smash-and-grab. (Laughter)
Dialogue: 0,0:02:21.85,0:02:24.55,Default,,0000,0000,0000,,And this is a clear indication
Dialogue: 0,0:02:24.55,0:02:27.16,Default,,0000,0000,0000,,that this is a valuable resource.
Dialogue: 0,0:02:27.16,0:02:31.29,Default,,0000,0000,0000,,And so valuable resources have to be looked after
Dialogue: 0,0:02:31.29,0:02:34.61,Default,,0000,0000,0000,,and guarded in a particular way, and we think
Dialogue: 0,0:02:34.61,0:02:37.91,Default,,0000,0000,0000,,the reason they roll the balls away is because of this,
Dialogue: 0,0:02:37.91,0:02:40.32,Default,,0000,0000,0000,,because of the competition that is involved
Dialogue: 0,0:02:40.32,0:02:42.19,Default,,0000,0000,0000,,in getting hold of that dung.
Dialogue: 0,0:02:42.19,0:02:45.39,Default,,0000,0000,0000,,So this dung pat was actually -- well, it was a dung pat
Dialogue: 0,0:02:45.39,0:02:47.84,Default,,0000,0000,0000,,15 minutes before this photograph was taken,
Dialogue: 0,0:02:47.84,0:02:50.88,Default,,0000,0000,0000,,and we think it's the intense competition
Dialogue: 0,0:02:50.88,0:02:54.76,Default,,0000,0000,0000,,that makes the beetles so well-adapted
Dialogue: 0,0:02:54.76,0:02:57.45,Default,,0000,0000,0000,,to rolling balls of dung.
Dialogue: 0,0:02:57.45,0:02:59.49,Default,,0000,0000,0000,,So what you've got to imagine here is this animal here
Dialogue: 0,0:02:59.49,0:03:03.09,Default,,0000,0000,0000,,moving across the African veld.
Dialogue: 0,0:03:03.09,0:03:06.44,Default,,0000,0000,0000,,Its head is down. It's walking backwards.
Dialogue: 0,0:03:06.44,0:03:11.81,Default,,0000,0000,0000,,It's the most bizarre way to actually transport your food in any particular direction,
Dialogue: 0,0:03:11.81,0:03:14.68,Default,,0000,0000,0000,,and at the same time it's got to deal with the heat.
Dialogue: 0,0:03:14.68,0:03:16.66,Default,,0000,0000,0000,,This is Africa. It's hot.
Dialogue: 0,0:03:16.66,0:03:18.37,Default,,0000,0000,0000,,So what I want to share with you now
Dialogue: 0,0:03:18.37,0:03:21.54,Default,,0000,0000,0000,,are some of the experiments that myself and my colleagues
Dialogue: 0,0:03:21.54,0:03:26.39,Default,,0000,0000,0000,,have used to investigate how dung beetles
Dialogue: 0,0:03:26.39,0:03:28.44,Default,,0000,0000,0000,,deal with these problems.
Dialogue: 0,0:03:28.44,0:03:30.98,Default,,0000,0000,0000,,So watch this beetle,
Dialogue: 0,0:03:30.98,0:03:35.12,Default,,0000,0000,0000,,and there's two things that I would like you to be aware of.
Dialogue: 0,0:03:35.12,0:03:37.68,Default,,0000,0000,0000,,The first is how it deals with this obstacle
Dialogue: 0,0:03:37.68,0:03:40.57,Default,,0000,0000,0000,,that we've put in its way. See, look, it does a little dance,
Dialogue: 0,0:03:40.57,0:03:43.50,Default,,0000,0000,0000,,and then it carries on in exactly the same direction
Dialogue: 0,0:03:43.50,0:03:47.19,Default,,0000,0000,0000,,that it took in the first place.
Dialogue: 0,0:03:47.19,0:03:50.96,Default,,0000,0000,0000,,A little dance, and then heads off in a particular direction.
Dialogue: 0,0:03:50.96,0:03:54.34,Default,,0000,0000,0000,,So clearly this animal knows where it's going
Dialogue: 0,0:03:54.34,0:03:55.68,Default,,0000,0000,0000,,and it knows where it wants to go,
Dialogue: 0,0:03:55.68,0:03:57.56,Default,,0000,0000,0000,,and that's a very, very important thing,
Dialogue: 0,0:03:57.56,0:03:59.98,Default,,0000,0000,0000,,because if you think about it, you're at the dung pile,
Dialogue: 0,0:03:59.98,0:04:04.50,Default,,0000,0000,0000,,you've got this great big pie that you want to get away from everybody else,
Dialogue: 0,0:04:04.50,0:04:07.39,Default,,0000,0000,0000,,and the quickest way to do it is in a straight line.
Dialogue: 0,0:04:07.39,0:04:11.77,Default,,0000,0000,0000,,So we gave them some more tasks to deal with,
Dialogue: 0,0:04:11.77,0:04:15.93,Default,,0000,0000,0000,,and what we did here is we turned the world
Dialogue: 0,0:04:15.93,0:04:19.61,Default,,0000,0000,0000,,under their feet. And watch its response.
Dialogue: 0,0:04:25.29,0:04:28.08,Default,,0000,0000,0000,,So this animal has actually had the whole world
Dialogue: 0,0:04:28.08,0:04:30.93,Default,,0000,0000,0000,,turned under its feet. It's turned by 90 degrees.
Dialogue: 0,0:04:30.93,0:04:33.40,Default,,0000,0000,0000,,But it doesn't flinch. It knows exactly where it wants to go,
Dialogue: 0,0:04:33.40,0:04:36.37,Default,,0000,0000,0000,,and it heads off in that particular direction.
Dialogue: 0,0:04:36.37,0:04:38.56,Default,,0000,0000,0000,,So our next question then was,
Dialogue: 0,0:04:38.56,0:04:40.52,Default,,0000,0000,0000,,how are they doing this?
Dialogue: 0,0:04:40.52,0:04:43.97,Default,,0000,0000,0000,,What are they doing? And there was a cue that was available to us.
Dialogue: 0,0:04:43.97,0:04:47.10,Default,,0000,0000,0000,,It was that every now and then they'd climb on top of the ball
Dialogue: 0,0:04:47.10,0:04:49.73,Default,,0000,0000,0000,,and they'd take a look at the world around them.
Dialogue: 0,0:04:49.73,0:04:51.45,Default,,0000,0000,0000,,And what do you think they could be looking at
Dialogue: 0,0:04:51.45,0:04:53.13,Default,,0000,0000,0000,,as they climb on top of the ball?
Dialogue: 0,0:04:53.13,0:04:56.68,Default,,0000,0000,0000,,What are the obvious cues that this animal could use
Dialogue: 0,0:04:56.68,0:05:00.86,Default,,0000,0000,0000,,to direct its movement? And the most obvious one
Dialogue: 0,0:05:00.86,0:05:05.08,Default,,0000,0000,0000,,is to look at the sky, and so we thought,
Dialogue: 0,0:05:05.08,0:05:07.34,Default,,0000,0000,0000,,now what could they be looking at in the sky?
Dialogue: 0,0:05:07.34,0:05:11.45,Default,,0000,0000,0000,,And the obvious thing to look at is the sun.
Dialogue: 0,0:05:11.45,0:05:14.40,Default,,0000,0000,0000,,So a classic experiment here,
Dialogue: 0,0:05:14.40,0:05:17.94,Default,,0000,0000,0000,,in that what we did was we moved the sun.
Dialogue: 0,0:05:17.94,0:05:20.68,Default,,0000,0000,0000,,What we're going to do now is shade the sun with a board
Dialogue: 0,0:05:20.68,0:05:22.66,Default,,0000,0000,0000,,and then move the sun with a mirror
Dialogue: 0,0:05:22.66,0:05:24.52,Default,,0000,0000,0000,,to a completely different position.
Dialogue: 0,0:05:24.52,0:05:26.43,Default,,0000,0000,0000,,And look at what the beetle does.
Dialogue: 0,0:05:26.43,0:05:29.26,Default,,0000,0000,0000,,It does a little double dance,
Dialogue: 0,0:05:29.26,0:05:31.54,Default,,0000,0000,0000,,and then it heads back in exactly the same direction
Dialogue: 0,0:05:31.54,0:05:33.95,Default,,0000,0000,0000,,it went in the first place.
Dialogue: 0,0:05:33.95,0:05:37.68,Default,,0000,0000,0000,,What happens now? So clearly they're looking at the sun.
Dialogue: 0,0:05:37.68,0:05:40.94,Default,,0000,0000,0000,,The sun is a very important cue in the sky for them.
Dialogue: 0,0:05:40.94,0:05:43.57,Default,,0000,0000,0000,,The thing is the sun is not always available to you,
Dialogue: 0,0:05:43.57,0:05:47.98,Default,,0000,0000,0000,,because at sunset it disappears below the horizon.
Dialogue: 0,0:05:47.98,0:05:50.57,Default,,0000,0000,0000,,What is happening in the sky here
Dialogue: 0,0:05:50.57,0:05:54.22,Default,,0000,0000,0000,,is that there's a great big pattern of polarized light in the sky
Dialogue: 0,0:05:54.22,0:05:57.98,Default,,0000,0000,0000,,that you and I can't see. It's the way our eyes are built.
Dialogue: 0,0:05:57.98,0:06:01.68,Default,,0000,0000,0000,,But the sun is at the horizon over here
Dialogue: 0,0:06:01.68,0:06:04.65,Default,,0000,0000,0000,,and we know that when the sun is at the horizon,
Dialogue: 0,0:06:04.65,0:06:06.19,Default,,0000,0000,0000,,say it's over on this side,
Dialogue: 0,0:06:06.19,0:06:10.78,Default,,0000,0000,0000,,there is a north-south, a huge pathway across the sky
Dialogue: 0,0:06:10.78,0:06:13.25,Default,,0000,0000,0000,,of polarized light that we can't see
Dialogue: 0,0:06:13.25,0:06:16.05,Default,,0000,0000,0000,,that the beetles can see.
Dialogue: 0,0:06:16.05,0:06:18.90,Default,,0000,0000,0000,,So how do we test that? Well, that's easy.
Dialogue: 0,0:06:18.90,0:06:21.85,Default,,0000,0000,0000,,What we do is we get a great big polarization filter,
Dialogue: 0,0:06:21.85,0:06:26.27,Default,,0000,0000,0000,,pop the beetle underneath it, and the filter is at right angles
Dialogue: 0,0:06:26.27,0:06:28.92,Default,,0000,0000,0000,,to the polarization pattern of the sky.
Dialogue: 0,0:06:28.92,0:06:33.09,Default,,0000,0000,0000,,The beetle comes out from underneath the filter
Dialogue: 0,0:06:33.09,0:06:35.59,Default,,0000,0000,0000,,and it does a right-hand turn,
Dialogue: 0,0:06:35.59,0:06:37.79,Default,,0000,0000,0000,,because it comes back under the sky
Dialogue: 0,0:06:37.79,0:06:40.61,Default,,0000,0000,0000,,that it was originally orientated to
Dialogue: 0,0:06:40.61,0:06:42.95,Default,,0000,0000,0000,,and then reorientates itself back
Dialogue: 0,0:06:42.95,0:06:46.87,Default,,0000,0000,0000,,to the direction it was originally going in.
Dialogue: 0,0:06:46.87,0:06:52.69,Default,,0000,0000,0000,,So obviously beetles can see polarized light.
Dialogue: 0,0:06:52.69,0:06:55.45,Default,,0000,0000,0000,,Okay, so what we've got so far is,
Dialogue: 0,0:06:55.45,0:06:58.22,Default,,0000,0000,0000,,what are beetles doing? They're rolling balls.
Dialogue: 0,0:06:58.22,0:07:01.24,Default,,0000,0000,0000,,How are they doing it? Well, they're rolling them in a straight line.
Dialogue: 0,0:07:01.24,0:07:04.82,Default,,0000,0000,0000,,How are they maintaining it in a particular straight line?
Dialogue: 0,0:07:04.82,0:07:07.51,Default,,0000,0000,0000,,Well, they're looking at celestial cues in the sky,
Dialogue: 0,0:07:07.51,0:07:09.76,Default,,0000,0000,0000,,some of which you and I can't see.
Dialogue: 0,0:07:09.76,0:07:11.44,Default,,0000,0000,0000,,But how do they pick up those celestial cues?
Dialogue: 0,0:07:11.44,0:07:14.48,Default,,0000,0000,0000,,That was what was of interest to us next.
Dialogue: 0,0:07:14.48,0:07:17.67,Default,,0000,0000,0000,,And it was this particular little behavior, the dance,
Dialogue: 0,0:07:17.67,0:07:20.59,Default,,0000,0000,0000,,that we thought was important, because look,
Dialogue: 0,0:07:20.59,0:07:22.15,Default,,0000,0000,0000,,it takes a pause every now and then,
Dialogue: 0,0:07:22.15,0:07:26.63,Default,,0000,0000,0000,,and then heads off in the direction that it wants to go in.
Dialogue: 0,0:07:26.63,0:07:30.86,Default,,0000,0000,0000,,So what are they doing when they do this dance?
Dialogue: 0,0:07:30.86,0:07:35.20,Default,,0000,0000,0000,,How far can we push them before they will reorientate themselves?
Dialogue: 0,0:07:35.20,0:07:38.70,Default,,0000,0000,0000,,And in this experiment here, what we did was we forced them
Dialogue: 0,0:07:38.70,0:07:41.36,Default,,0000,0000,0000,,into a channel, and you can see he wasn't
Dialogue: 0,0:07:41.36,0:07:44.10,Default,,0000,0000,0000,,particularly forced into this particular channel,
Dialogue: 0,0:07:44.10,0:07:49.40,Default,,0000,0000,0000,,and we gradually displaced the beetle by 180 degrees
Dialogue: 0,0:07:49.40,0:07:53.14,Default,,0000,0000,0000,,until this individual ends up going in exactly the opposite direction
Dialogue: 0,0:07:53.14,0:07:55.70,Default,,0000,0000,0000,,that it wanted to go in, in the first place.
Dialogue: 0,0:07:55.70,0:07:58.50,Default,,0000,0000,0000,,And let's see what his reaction is
Dialogue: 0,0:07:58.50,0:08:01.11,Default,,0000,0000,0000,,as he's headed through 90 degrees here,
Dialogue: 0,0:08:01.11,0:08:03.22,Default,,0000,0000,0000,,and now he's going to -- when he ends up down here,
Dialogue: 0,0:08:03.22,0:08:06.26,Default,,0000,0000,0000,,he's going to be 180 degrees in the wrong direction.
Dialogue: 0,0:08:06.26,0:08:08.56,Default,,0000,0000,0000,,And see what his response is.
Dialogue: 0,0:08:08.56,0:08:11.75,Default,,0000,0000,0000,,He does a little dance, he turns around,
Dialogue: 0,0:08:11.75,0:08:15.49,Default,,0000,0000,0000,,and heads back in this. He knows exactly where he's going.
Dialogue: 0,0:08:15.49,0:08:17.77,Default,,0000,0000,0000,,He knows exactly what the problem is,
Dialogue: 0,0:08:17.77,0:08:19.36,Default,,0000,0000,0000,,and he knows exactly how to deal with it,
Dialogue: 0,0:08:19.36,0:08:22.06,Default,,0000,0000,0000,,and the dance is this transition behavior
Dialogue: 0,0:08:22.06,0:08:24.87,Default,,0000,0000,0000,,that allows them to reorientate themselves.
Dialogue: 0,0:08:24.87,0:08:29.66,Default,,0000,0000,0000,,So that's the dance, but after spending many years
Dialogue: 0,0:08:29.66,0:08:33.32,Default,,0000,0000,0000,,sitting in the African bush watching dung beetles on nice hot days,
Dialogue: 0,0:08:33.32,0:08:35.67,Default,,0000,0000,0000,,we noticed that there was another behavior
Dialogue: 0,0:08:35.67,0:08:38.16,Default,,0000,0000,0000,,associated with the dance behavior.
Dialogue: 0,0:08:38.16,0:08:42.10,Default,,0000,0000,0000,,Every now and then, when they climb on top of the ball,
Dialogue: 0,0:08:42.10,0:08:45.50,Default,,0000,0000,0000,,they wipe their face.
Dialogue: 0,0:08:45.50,0:08:48.47,Default,,0000,0000,0000,,And you see him do it again.
Dialogue: 0,0:08:48.47,0:08:51.45,Default,,0000,0000,0000,,Now we thought, now what could be going on here?
Dialogue: 0,0:08:51.45,0:08:54.35,Default,,0000,0000,0000,,Clearly the ground is very hot, and when the ground is hot,
Dialogue: 0,0:08:54.35,0:08:57.09,Default,,0000,0000,0000,,they dance more often, and when they do this particular dance,
Dialogue: 0,0:08:57.09,0:08:59.06,Default,,0000,0000,0000,,they wipe the bottom of their face.
Dialogue: 0,0:08:59.06,0:09:01.76,Default,,0000,0000,0000,,And we thought that it could be a thermoregulatory behavior.
Dialogue: 0,0:09:01.76,0:09:03.76,Default,,0000,0000,0000,,We thought that maybe what they're doing is trying to
Dialogue: 0,0:09:03.76,0:09:07.21,Default,,0000,0000,0000,,get off the hot soil and also spitting onto their face
Dialogue: 0,0:09:07.21,0:09:09.62,Default,,0000,0000,0000,,to cool their head down.
Dialogue: 0,0:09:09.62,0:09:14.06,Default,,0000,0000,0000,,So what we did was design a couple of arenas.
Dialogue: 0,0:09:14.06,0:09:16.16,Default,,0000,0000,0000,,one was hot, one was cold.
Dialogue: 0,0:09:16.16,0:09:18.54,Default,,0000,0000,0000,,We shaded this one. We left that one hot.
Dialogue: 0,0:09:18.54,0:09:22.01,Default,,0000,0000,0000,,And then what we did was we filmed them with a thermal camera.
Dialogue: 0,0:09:22.01,0:09:26.42,Default,,0000,0000,0000,,So what you're looking at here is a heat image
Dialogue: 0,0:09:26.42,0:09:30.34,Default,,0000,0000,0000,,of the system, and what you can see here emerging
Dialogue: 0,0:09:30.34,0:09:33.95,Default,,0000,0000,0000,,from the poo is a cool dung ball.
Dialogue: 0,0:09:33.95,0:09:37.23,Default,,0000,0000,0000,,So the truth is, if you look at the temperature over here,
Dialogue: 0,0:09:37.23,0:09:42.21,Default,,0000,0000,0000,,dung is cool. (Laughter)
Dialogue: 0,0:09:42.21,0:09:45.43,Default,,0000,0000,0000,,So all we're interested in here is comparing the temperature
Dialogue: 0,0:09:45.43,0:09:48.07,Default,,0000,0000,0000,,of the beetle against the background.
Dialogue: 0,0:09:48.07,0:09:52.01,Default,,0000,0000,0000,,So the background here is around about 50 degrees centigrade.
Dialogue: 0,0:09:52.01,0:09:54.62,Default,,0000,0000,0000,,The beetle itself and the ball are probably around about
Dialogue: 0,0:09:54.62,0:09:56.69,Default,,0000,0000,0000,,30 to 35 degrees centigrade,
Dialogue: 0,0:09:56.69,0:09:59.36,Default,,0000,0000,0000,,so this is a great big ball of ice cream
Dialogue: 0,0:09:59.36,0:10:02.49,Default,,0000,0000,0000,,that this beetle is now transporting across the hot veld.
Dialogue: 0,0:10:02.49,0:10:05.19,Default,,0000,0000,0000,,It isn't climbing. It isn't dancing, because
Dialogue: 0,0:10:05.19,0:10:08.03,Default,,0000,0000,0000,,its body temperature is actually relatively low.
Dialogue: 0,0:10:08.03,0:10:11.10,Default,,0000,0000,0000,,It's about the same as yours and mine.
Dialogue: 0,0:10:11.10,0:10:16.07,Default,,0000,0000,0000,,And what's of interest here is that little brain is quite cool.
Dialogue: 0,0:10:16.07,0:10:20.37,Default,,0000,0000,0000,,But if we contrast now what happens in a hot environment,
Dialogue: 0,0:10:20.37,0:10:22.52,Default,,0000,0000,0000,,look at the temperature of the soil.
Dialogue: 0,0:10:22.52,0:10:25.97,Default,,0000,0000,0000,,It's up around 55 to 60 degrees centigrade.
Dialogue: 0,0:10:25.97,0:10:29.42,Default,,0000,0000,0000,,Watch how often the beetle dances.
Dialogue: 0,0:10:29.42,0:10:33.96,Default,,0000,0000,0000,,And look at its front legs. They're roaringly hot.
Dialogue: 0,0:10:33.96,0:10:36.88,Default,,0000,0000,0000,,So the ball leaves a little thermal shadow,
Dialogue: 0,0:10:36.88,0:10:38.82,Default,,0000,0000,0000,,and the beetle climbs on top of the ball
Dialogue: 0,0:10:38.82,0:10:43.45,Default,,0000,0000,0000,,and wipes its face, and all the time it's trying to cool itself down,
Dialogue: 0,0:10:43.45,0:10:49.12,Default,,0000,0000,0000,,we think, and avoid the hot sand that it's walking across.
Dialogue: 0,0:10:49.12,0:10:53.06,Default,,0000,0000,0000,,And what we did then was put little boots on these legs,
Dialogue: 0,0:10:53.06,0:10:56.02,Default,,0000,0000,0000,,because this was a way to test if the legs
Dialogue: 0,0:10:56.02,0:10:59.78,Default,,0000,0000,0000,,were involved in sensing the temperature of the soil.
Dialogue: 0,0:10:59.78,0:11:03.75,Default,,0000,0000,0000,,And if you look over here, with boots they climb onto the ball
Dialogue: 0,0:11:03.75,0:11:07.94,Default,,0000,0000,0000,,far less often when they had no boots on.
Dialogue: 0,0:11:07.94,0:11:10.27,Default,,0000,0000,0000,,So we described these as cool boots.
Dialogue: 0,0:11:10.27,0:11:13.19,Default,,0000,0000,0000,,It was a dental compound that we used to make these boots.
Dialogue: 0,0:11:13.19,0:11:16.08,Default,,0000,0000,0000,,And we also cooled down the dung ball, so we were able
Dialogue: 0,0:11:16.08,0:11:19.73,Default,,0000,0000,0000,,to put the ball in the fridge, gave them a nice cool dung ball,
Dialogue: 0,0:11:19.73,0:11:22.28,Default,,0000,0000,0000,,and they climbed onto that ball far less often
Dialogue: 0,0:11:22.28,0:11:23.82,Default,,0000,0000,0000,,than when they had a hot ball.
Dialogue: 0,0:11:23.82,0:11:26.79,Default,,0000,0000,0000,,So this is called stilting. It's a thermal behavior
Dialogue: 0,0:11:26.79,0:11:28.70,Default,,0000,0000,0000,,that you and I do if we cross the beach,
Dialogue: 0,0:11:28.70,0:11:31.42,Default,,0000,0000,0000,,we jump onto a towel, somebody has this towel --
Dialogue: 0,0:11:31.42,0:11:32.64,Default,,0000,0000,0000,,"Sorry, I've jumped onto your towel." --
Dialogue: 0,0:11:32.64,0:11:35.20,Default,,0000,0000,0000,,and then you scuttle across onto somebody else's towel,
Dialogue: 0,0:11:35.20,0:11:37.41,Default,,0000,0000,0000,,and that way you don't burn your feet.
Dialogue: 0,0:11:37.41,0:11:40.21,Default,,0000,0000,0000,,And that's exactly what the beetles are doing here.
Dialogue: 0,0:11:40.21,0:11:43.42,Default,,0000,0000,0000,,However, there's one more story I'd like to share with you,
Dialogue: 0,0:11:43.42,0:11:44.100,Default,,0000,0000,0000,,and that's this particular species.
Dialogue: 0,0:11:44.100,0:11:47.79,Default,,0000,0000,0000,,It's from a genus called Pachysoma.
Dialogue: 0,0:11:47.79,0:11:50.82,Default,,0000,0000,0000,,There are 13 species in the genus, and they have
Dialogue: 0,0:11:50.82,0:11:56.96,Default,,0000,0000,0000,,a particular behavior that I think you will find interesting.
Dialogue: 0,0:11:56.96,0:12:01.62,Default,,0000,0000,0000,,This is a dung beetle. Watch what he's doing.
Dialogue: 0,0:12:01.62,0:12:04.31,Default,,0000,0000,0000,,Can you spot the difference?
Dialogue: 0,0:12:04.31,0:12:07.54,Default,,0000,0000,0000,,They don't normally go this slowly. It's in slow motion.
Dialogue: 0,0:12:07.54,0:12:09.34,Default,,0000,0000,0000,,but it's walking forwards,
Dialogue: 0,0:12:09.34,0:12:12.90,Default,,0000,0000,0000,,and it's actually taking a pellet of dry dung with it.
Dialogue: 0,0:12:12.90,0:12:15.35,Default,,0000,0000,0000,,This is a different species in the same genus
Dialogue: 0,0:12:15.35,0:12:19.22,Default,,0000,0000,0000,,but exactly the same foraging behavior.
Dialogue: 0,0:12:19.22,0:12:22.01,Default,,0000,0000,0000,,There's one more interesting aspect of this
Dialogue: 0,0:12:22.01,0:12:26.32,Default,,0000,0000,0000,,dung beetle's behavior that we found quite fascinating,
Dialogue: 0,0:12:26.32,0:12:30.82,Default,,0000,0000,0000,,and that's that it forages and provisions a nest.
Dialogue: 0,0:12:30.82,0:12:33.51,Default,,0000,0000,0000,,So watch this individual here, and what he's trying to do
Dialogue: 0,0:12:33.51,0:12:36.23,Default,,0000,0000,0000,,is set up a nest.
Dialogue: 0,0:12:36.23,0:12:37.94,Default,,0000,0000,0000,,And he doesn't like this first position,
Dialogue: 0,0:12:37.94,0:12:39.56,Default,,0000,0000,0000,,but he comes up with a second position,
Dialogue: 0,0:12:39.56,0:12:43.42,Default,,0000,0000,0000,,and about 50 minutes later, that nest is finished,
Dialogue: 0,0:12:43.42,0:12:47.15,Default,,0000,0000,0000,,and he heads off to forage and provision
Dialogue: 0,0:12:47.15,0:12:49.50,Default,,0000,0000,0000,,at a pile of dry dung pellets.
Dialogue: 0,0:12:49.50,0:12:52.67,Default,,0000,0000,0000,,And what I want you to notice is the outward path
Dialogue: 0,0:12:52.67,0:12:57.28,Default,,0000,0000,0000,,compared to the homeward path, and compare the two.
Dialogue: 0,0:12:57.28,0:12:59.94,Default,,0000,0000,0000,,And by and large, you'll see that the homeward path
Dialogue: 0,0:12:59.94,0:13:02.77,Default,,0000,0000,0000,,is far more direct than the outward path.
Dialogue: 0,0:13:02.77,0:13:05.58,Default,,0000,0000,0000,,On the outward path, he's always on the lookout
Dialogue: 0,0:13:05.58,0:13:08.05,Default,,0000,0000,0000,,for a new blob of dung.
Dialogue: 0,0:13:08.05,0:13:09.60,Default,,0000,0000,0000,,On the way home, he knows where home is,
Dialogue: 0,0:13:09.60,0:13:12.82,Default,,0000,0000,0000,,and he wants to go straight to it.
Dialogue: 0,0:13:12.82,0:13:16.39,Default,,0000,0000,0000,,The important thing here is that this is not a one-way trip,
Dialogue: 0,0:13:16.39,0:13:19.78,Default,,0000,0000,0000,,as in most dung beetles. The trip here is repeated
Dialogue: 0,0:13:19.78,0:13:24.09,Default,,0000,0000,0000,,back and forth between a provisioning site and a nest site.
Dialogue: 0,0:13:24.09,0:13:25.03,Default,,0000,0000,0000,,And watch, you're going to see
Dialogue: 0,0:13:25.03,0:13:29.04,Default,,0000,0000,0000,,another South African crime taking place right now. (Laughter)
Dialogue: 0,0:13:29.04,0:13:33.65,Default,,0000,0000,0000,,And his neighbor steals one of his dung pellets.
Dialogue: 0,0:13:33.65,0:13:36.79,Default,,0000,0000,0000,,So what we're looking at here
Dialogue: 0,0:13:36.79,0:13:40.12,Default,,0000,0000,0000,,is a behavior called path integration.
Dialogue: 0,0:13:40.12,0:13:42.74,Default,,0000,0000,0000,,And what's taking place is that the beetle
Dialogue: 0,0:13:42.74,0:13:47.04,Default,,0000,0000,0000,,has got a home spot, it goes out on a convoluted path
Dialogue: 0,0:13:47.04,0:13:50.13,Default,,0000,0000,0000,,looking for food, and then when it finds food,
Dialogue: 0,0:13:50.13,0:13:54.44,Default,,0000,0000,0000,,it heads straight home. It knows exactly where its home is.
Dialogue: 0,0:13:54.44,0:13:57.46,Default,,0000,0000,0000,,Now there's two ways it could be doing that,
Dialogue: 0,0:13:57.46,0:14:00.42,Default,,0000,0000,0000,,and we can test that by displacing the beetle
Dialogue: 0,0:14:00.42,0:14:03.12,Default,,0000,0000,0000,,to a new position when it's at the foraging site.
Dialogue: 0,0:14:03.12,0:14:06.41,Default,,0000,0000,0000,,If it's using landmarks, it will find its home.
Dialogue: 0,0:14:06.41,0:14:09.83,Default,,0000,0000,0000,,If it is using something called path integration,
Dialogue: 0,0:14:09.83,0:14:13.61,Default,,0000,0000,0000,,it will not find its home. It will arrive at the wrong spot,
Dialogue: 0,0:14:13.61,0:14:16.04,Default,,0000,0000,0000,,and what it's doing here if it's using path integration
Dialogue: 0,0:14:16.04,0:14:19.91,Default,,0000,0000,0000,,is it's counting its steps or measuring the distance out in this direction.
Dialogue: 0,0:14:19.91,0:14:23.60,Default,,0000,0000,0000,,It knows the bearing home, and it knows it should be in that direction.
Dialogue: 0,0:14:23.60,0:14:26.73,Default,,0000,0000,0000,,If you displace it, it ends up in the wrong place.
Dialogue: 0,0:14:26.73,0:14:29.31,Default,,0000,0000,0000,,So let's see what happens when we put this beetle
Dialogue: 0,0:14:29.31,0:14:32.63,Default,,0000,0000,0000,,to the test with a similar experiment.
Dialogue: 0,0:14:32.63,0:14:37.01,Default,,0000,0000,0000,,So here's our cunning experimenter.
Dialogue: 0,0:14:37.01,0:14:39.41,Default,,0000,0000,0000,,He displaces the beetle,
Dialogue: 0,0:14:39.41,0:14:44.26,Default,,0000,0000,0000,,and now we have to see what is going to take place.
Dialogue: 0,0:14:44.26,0:14:47.36,Default,,0000,0000,0000,,What we've got is a burrow. That's where the forage was.
Dialogue: 0,0:14:47.36,0:14:50.30,Default,,0000,0000,0000,,The forage has been displaced to a new position.
Dialogue: 0,0:14:50.30,0:14:52.66,Default,,0000,0000,0000,,If he's using landmark orientation,
Dialogue: 0,0:14:52.66,0:14:54.42,Default,,0000,0000,0000,,he should be able to find the burrow,
Dialogue: 0,0:14:54.42,0:14:57.14,Default,,0000,0000,0000,,because he'll be able to recognize the landmarks around it.
Dialogue: 0,0:14:57.14,0:15:00.19,Default,,0000,0000,0000,,If he's using path integration,
Dialogue: 0,0:15:00.19,0:15:03.91,Default,,0000,0000,0000,,then it should end up in the wrong spot over here.
Dialogue: 0,0:15:03.91,0:15:06.22,Default,,0000,0000,0000,,So let's watch what happens
Dialogue: 0,0:15:06.22,0:15:09.51,Default,,0000,0000,0000,,when we put the beetle through the whole test.
Dialogue: 0,0:15:09.51,0:15:11.51,Default,,0000,0000,0000,,So there he is there.
Dialogue: 0,0:15:11.51,0:15:17.77,Default,,0000,0000,0000,,He's about to head home, and look what happens.
Dialogue: 0,0:15:17.77,0:15:20.26,Default,,0000,0000,0000,,Shame.
Dialogue: 0,0:15:20.26,0:15:22.50,Default,,0000,0000,0000,,It hasn't a clue.
Dialogue: 0,0:15:22.50,0:15:25.42,Default,,0000,0000,0000,,It starts to search for its house in the right distance
Dialogue: 0,0:15:25.42,0:15:31.39,Default,,0000,0000,0000,,away from the food, but it is clearly completely lost.
Dialogue: 0,0:15:31.39,0:15:35.61,Default,,0000,0000,0000,,So we know now that this animal uses path integration
Dialogue: 0,0:15:35.61,0:15:39.69,Default,,0000,0000,0000,,to find its way around, and the callous experimenter
Dialogue: 0,0:15:39.69,0:15:42.81,Default,,0000,0000,0000,,leads it top left and leaves it. (Laughter)
Dialogue: 0,0:15:42.81,0:15:46.86,Default,,0000,0000,0000,,So what we're looking at here are a group of animals
Dialogue: 0,0:15:46.86,0:15:48.94,Default,,0000,0000,0000,,that use a compass, and they use the sun as a compass
Dialogue: 0,0:15:48.94,0:15:50.58,Default,,0000,0000,0000,,to find their way around,
Dialogue: 0,0:15:50.58,0:15:53.11,Default,,0000,0000,0000,,and they have some sort of system
Dialogue: 0,0:15:53.11,0:15:55.07,Default,,0000,0000,0000,,for measuring that distance,
Dialogue: 0,0:15:55.07,0:15:58.41,Default,,0000,0000,0000,,and we know that these species here actually
Dialogue: 0,0:15:58.41,0:16:01.09,Default,,0000,0000,0000,,count the steps. That's what they use as an odometer,
Dialogue: 0,0:16:01.09,0:16:06.23,Default,,0000,0000,0000,,a step-counting system, to find their way back home.
Dialogue: 0,0:16:06.23,0:16:09.05,Default,,0000,0000,0000,,We don't know yet what dung beetles use.
Dialogue: 0,0:16:09.05,0:16:11.33,Default,,0000,0000,0000,,So what have we learned from these animals
Dialogue: 0,0:16:11.33,0:16:14.33,Default,,0000,0000,0000,,with a brain that's the size of a grain of rice?
Dialogue: 0,0:16:14.33,0:16:18.44,Default,,0000,0000,0000,,Well, we know that they can roll balls in a straight line
Dialogue: 0,0:16:18.44,0:16:20.58,Default,,0000,0000,0000,,using celestial cues.
Dialogue: 0,0:16:20.58,0:16:23.71,Default,,0000,0000,0000,,We know that the dance behavior is an orientation behavior
Dialogue: 0,0:16:23.71,0:16:26.13,Default,,0000,0000,0000,,and it's also a thermoregulation behavior,
Dialogue: 0,0:16:26.13,0:16:30.32,Default,,0000,0000,0000,,and we also know that they use a path integration system
Dialogue: 0,0:16:30.32,0:16:32.41,Default,,0000,0000,0000,,for finding their way home.
Dialogue: 0,0:16:32.41,0:16:36.58,Default,,0000,0000,0000,,So for a small animal dealing with a fairly revolting substance
Dialogue: 0,0:16:36.58,0:16:39.35,Default,,0000,0000,0000,,we can actually learn an awful lot from these things
Dialogue: 0,0:16:39.35,0:16:42.98,Default,,0000,0000,0000,,doing behaviors that you and I couldn't possibly do.
Dialogue: 0,0:16:42.98,0:16:46.98,Default,,0000,0000,0000,,Thank you. (Applause)