This is poo, and what I want to do today is share my passion for poo with you, which might be quite difficult, but I think what you might find more fascinating is the way these small animals deal with poo.
這是便便, 我今天想要做的是與你們分享 我對便便的熱愛。 這可能是很困難的 但我想你們會發現 這些小動物處理便便的方式是非常迷人的。
So this animal here has got a brain about the size of a grain of rice, and yet it can do things that you and I couldn't possibly entertain the idea of doing. And basically it's all evolved to handle its food source, which is dung.
這動物的腦大小 只有米一般大,但仍然可以做一些 你我想都不會想的事情。 基本上這都是由食物源而來的, 也就是糞。
So the question is, where do we start this story? And it seems appropriate to start at the end, because this is a waste product that comes out of other animals, but it still contains nutrients and there are sufficient nutrients in there for dung beetles basically to make a living, and so dung beetles eat dung, and their larvae are also dung-feeders. They are grown completely in a ball of dung. Within South Africa, we've got about 800 species of dung beetles, in Africa we've got 2,000 species of dung beetles, and in the world we have about 6,000 species of dung beetles. So, according to dung beetles, dung is pretty good.
所以,問題是我們該從哪裡說起呢? 看來,從末端談起適合適的。 因為這是一種出自其它動物的廢物, 但是仍然含有營養素, 且所含的養分足以讓 糞甲蟲生存。 所以糞甲蟲吃糞便, 它們的幼蟲也是食糞的。 他們整個生長過程都在糞便中完成。 在南非,我們有約 800 種糞甲蟲, 在非洲有 2000 種類的糞甲蟲, 而在全球,有約 6000 種糞甲蟲。 對糞甲蟲來說,糞便是很好的。
Unless you're prepared to get dung under your fingernails and root through the dung itself, you'll never see 90 percent of the dung beetle species, because they go directly into the dung, straight down below it, and then they shuttle back and forth between the dung at the soil surface and a nest they make underground.
除非你準備好讓糞便進到你的指甲下 和根本的探究糞便本身, 你永遠看不到90%的糞甲蟲物種。 因為他們直接進到糞便深處, 然後他們來回穿梭於 在土壤表面的糞便 和他們在地下的巢。
So the question is, how do they deal with this material? And most dung beetles actually wrap it into a package of some sort. Ten percent of the species actually make a ball, and this ball they roll away from the dung source, usually bury it at a remote place away from the dung source, and they have a very particular behavior by which they are able to roll their balls. So this is a very proud owner of a beautiful dung ball. You can see it's a male because he's got a little hair on the back of his legs there, and he's clearly very pleased about what he's sitting on there. And then he's about to become a victim of a vicious smash-and-grab. (Laughter) And this is a clear indication that this is a valuable resource. And so valuable resources have to be looked after and guarded in a particular way, and we think the reason they roll the balls away is because of this, because of the competition that is involved in getting hold of that dung. So this dung pat was actually -- well, it was a dung pat 15 minutes before this photograph was taken, and we think it's the intense competition that makes the beetles so well-adapted to rolling balls of dung.
所以,他們是如何利用這樣的材料呢? 大多數糞甲蟲將其包裝。 10%的物種包成球狀, 並將這些球滾離糞源, 通常把它埋在離糞源教遠的地方, 且他們滾球的方式 是非常特定的。 這是非常驕傲地美麗糞球擁有者。 你可以看到牠是公的, 因為牠的腿後面有毛髮, 且牠對於自己正坐著的東西顯然非常高興。 然後牠就要成為 惡毒的破窗行竊行為的受害者。(笑聲) 這很明確地表示 這是一個寶貴的資源。 因此,寶貴的資源必須得到照顧和 特定的看守,我們認為 這是牠們將糞球滾走的的原因, 因為擁有糞便 涉及競爭。 所以這糞墊是--嗯,至少在 這張照片拍攝前15 分鐘是糞墊, 我們認為這激烈的競爭 是使糞甲蟲非常會 滾糞球的原因。
So what you've got to imagine here is this animal here moving across the African veld. Its head is down. It's walking backwards. It's the most bizarre way to actually transport your food in any particular direction, and at the same time it's got to deal with the heat. This is Africa. It's hot.
所以你想像的是這動物 在非洲草原上移動。 牠的頭是向下,牠正向後走。 這是往特定方向運輸食物最離奇的方式, 並在同一時間還得耐熱。 這是非洲。很熱的。
So what I want to share with you now are some of the experiments that myself and my colleagues have used to investigate how dung beetles deal with these problems.
所以我現在想要與你們分享 一些我和同事們做的實驗 來研究糞甲蟲如何 處理這些問題。
So watch this beetle, and there's two things that I would like you to be aware of. The first is how it deals with this obstacle that we've put in its way. See, look, it does a little dance, and then it carries on in exactly the same direction that it took in the first place. A little dance, and then heads off in a particular direction. So clearly this animal knows where it's going and it knows where it wants to go, and that's a very, very important thing, because if you think about it, you're at the dung pile, you've got this great big pie that you want to get away from everybody else, and the quickest way to do it is in a straight line. So we gave them some more tasks to deal with, and what we did here is we turned the world under their feet. And watch its response. So this animal has actually had the whole world turned under its feet. It's turned by 90 degrees. But it doesn't flinch. It knows exactly where it wants to go, and it heads off in that particular direction.
所以看這只糞甲蟲, 我想要你們注意兩件事。 第一是如何處理我們放在牠的路徑中的障礙物。 看看,牠跳一段小舞蹈, 然後它往牠一開始完全相同的 方向前進。 一小段舞,然後往特定的方向前進。 很顯然的,這動物知道牠要去哪裡 且知道牠想去哪裡, 且這是非常、 非常重要的, 因為如果你想想看,你在糞堆中, 你有一塊你想要搬離其它人的大餅, 且最快捷的方法就是直線前進。 所以我們給了牠們更多的任務, 在這裡做的就是我們在牠們的腳下 旋轉世界。觀察牠的反應。 所以實際上整個世界被旋轉了, 旋轉了 90 度。 但牠不會退縮。牠很確切地知道牠想要去哪, 且牠仍朝著那個方向前進。
So our next question then was, how are they doing this? What are they doing? And there was a cue that was available to us. It was that every now and then they'd climb on top of the ball and they'd take a look at the world around them. And what do you think they could be looking at as they climb on top of the ball? What are the obvious cues that this animal could use to direct its movement? And the most obvious one is to look at the sky, and so we thought, now what could they be looking at in the sky? And the obvious thing to look at is the sun. So a classic experiment here, in that what we did was we moved the sun. What we're going to do now is shade the sun with a board and then move the sun with a mirror to a completely different position. And look at what the beetle does. It does a little double dance, and then it heads back in exactly the same direction it went in the first place. What happens now? So clearly they're looking at the sun. The sun is a very important cue in the sky for them.
所以我們接下來的問題是 牠們如何做到的? 牠們在做什麼?我們有個線索。 就是牠們有時候會爬到球上 看看周圍的世界。 你認為牠們爬上球時 在看什麼? 這種動物最有可能找什麼樣的線索 來幫助牠的直線運動?最直接的 是看看天空,於是我們就想, 牠們可能在天空中的什麼? 最直接的是看太陽。 所以一個經典的實驗 就是改變太陽的位置。 我們罩住太陽 然後利用鏡子 將太陽移到完全不同的位置。 然後觀察糞甲蟲。 它跳一小段舞, 然後牠回到跟一開始 完全相同的方向。 發生了什麼?很顯然牠們正在看太陽。 太陽對牠們來說是天空中是非常重要的線索。
The thing is the sun is not always available to you, because at sunset it disappears below the horizon. What is happening in the sky here is that there's a great big pattern of polarized light in the sky that you and I can't see. It's the way our eyes are built. But the sun is at the horizon over here and we know that when the sun is at the horizon, say it's over on this side, there is a north-south, a huge pathway across the sky of polarized light that we can't see that the beetles can see. So how do we test that? Well, that's easy. What we do is we get a great big polarization filter, pop the beetle underneath it, and the filter is at right angles to the polarization pattern of the sky. The beetle comes out from underneath the filter and it does a right-hand turn, because it comes back under the sky that it was originally orientated to and then reorientates itself back to the direction it was originally going in. So obviously beetles can see polarized light.
但問題是太陽並不永遠可以用, 因為日落後它會消失在地平線下。 在這裡天空中 有大型偏振光圖樣 但這是你、我看不見的。我們的眼睛就是這樣。 但是在這裡,太陽在地平線, 而我們知道,當太陽在地平線時, 假設它在這一側, 穿過天空南北有一道巨大的、 我們看不見的偏振光 但甲蟲是看得到的。 所以我們要怎麼測試呢?這很容易。 我們用一巨大的偏振濾光片, 將甲蟲放在下面,濾片與天空的偏振 呈直角。 甲蟲從篩選器下出來 然後向右轉彎, 因為牠回到原本的天空下, 回到最初的定位, 又重新 回到本來的方向。 所以很明顯地甲蟲可以看到偏振光。
Okay, so what we've got so far is, what are beetles doing? They're rolling balls. How are they doing it? Well, they're rolling them in a straight line. How are they maintaining it in a particular straight line? Well, they're looking at celestial cues in the sky, some of which you and I can't see.
好,所以目前為止我們知道 甲蟲的什麼?牠們會滾球。 牠們如何滾?滾在一條直線上。 牠們如何保持在特定的直線? 牠們在看天空中的天體線索, 其中一些是我們看不見的。
But how do they pick up those celestial cues? That was what was of interest to us next. And it was this particular little behavior, the dance, that we thought was important, because look, it takes a pause every now and then, and then heads off in the direction that it wants to go in. So what are they doing when they do this dance? How far can we push them before they will reorientate themselves? And in this experiment here, what we did was we forced them into a channel, and you can see he wasn't particularly forced into this particular channel, and we gradually displaced the beetle by 180 degrees until this individual ends up going in exactly the opposite direction that it wanted to go in, in the first place. And let's see what his reaction is as he's headed through 90 degrees here, and now he's going to -- when he ends up down here, he's going to be 180 degrees in the wrong direction. And see what his response is. He does a little dance, he turns around, and heads back in this. He knows exactly where he's going. He knows exactly what the problem is, and he knows exactly how to deal with it, and the dance is this transition behavior that allows them to reorientate themselves.
但牠們如何偵測這些天體線索? 那正是我們的下一步。 這種跳舞的行為 讓我們覺得是重要的, 因為看牠時不時暫停一下, 然後爬往牠想要去的方向。 所以牠們在跳這種舞蹈時到底在做什麼呢? 所以在牠們重新定位前我們可以改變多少呢? 在這個實驗中,我們強迫牠們 進入一個通道,你可以看到牠並不是 特別被強迫到此特定的通道, 我們逐漸將甲蟲轉 180 度 直到牠跟原來的方向 完全相反。 讓我們看看牠的反應是什麼。 在這裡轉 90 度了, 現在,牠要 — 當牠到尾端時 牠將會轉了 180 度。 看看牠的反應是什麼。 牠跳一小段舞,轉過身, 再回到這裡面。牠完全知道牠要去哪。 牠知道問題是什麼, 並知道如何處理, 且舞蹈是這中間的過渡行為 讓牠們能夠重新調整。
So that's the dance, but after spending many years sitting in the African bush watching dung beetles on nice hot days, we noticed that there was another behavior associated with the dance behavior. Every now and then, when they climb on top of the ball, they wipe their face. And you see him do it again. Now we thought, now what could be going on here? Clearly the ground is very hot, and when the ground is hot, they dance more often, and when they do this particular dance, they wipe the bottom of their face. And we thought that it could be a thermoregulatory behavior. We thought that maybe what they're doing is trying to get off the hot soil and also spitting onto their face to cool their head down.
就是這個舞蹈。但經過多年 坐在很熱的非洲叢林中看甲蟲, 我們注意到有另一個 與舞蹈行為相關聯的行為。 時不時,牠們會爬到球上 擦拭自己的臉。 你看到牠又做了一次。 所以我們在想這裡是發生什麼事呢? 很顯然地是很熱的,且當地面很熱時, 牠們更常跳舞的時候,且當牠們跳舞時, 牠們會擦自己臉的底部。 我們認為這可能是一種體溫調節的行為。 我們猜測牠們正在試著 離開發燙的土壤並往臉上吐液體 來將頭部降溫。
So what we did was design a couple of arenas. one was hot, one was cold. We shaded this one. We left that one hot. And then what we did was we filmed them with a thermal camera. So what you're looking at here is a heat image of the system, and what you can see here emerging from the poo is a cool dung ball. So the truth is, if you look at the temperature over here, dung is cool. (Laughter)
所以我們設計了一些環境。 一熱一冷。 我們將這個放在陰影下,另外那個就在熱環境下。 然後我們用熱相機拍攝牠們。 你們現在正在看的這是熱圖像, 你們可以看到從糞便出來的 是一個冷的糞球。 因此,事實是,如果從溫度角度看, 糞便是很冷的。(笑聲)
So all we're interested in here is comparing the temperature of the beetle against the background. So the background here is around about 50 degrees centigrade. The beetle itself and the ball are probably around about 30 to 35 degrees centigrade, so this is a great big ball of ice cream that this beetle is now transporting across the hot veld. It isn't climbing. It isn't dancing, because its body temperature is actually relatively low. It's about the same as yours and mine. And what's of interest here is that little brain is quite cool. But if we contrast now what happens in a hot environment, look at the temperature of the soil. It's up around 55 to 60 degrees centigrade. Watch how often the beetle dances. And look at its front legs. They're roaringly hot. So the ball leaves a little thermal shadow, and the beetle climbs on top of the ball and wipes its face, and all the time it's trying to cool itself down, we think, and avoid the hot sand that it's walking across.
所以我們有興趣的是比較 甲蟲和環境的溫度。 這裡環境溫度約攝氏 50 度。 甲蟲本身和糞球 大約是攝氏30 到 35 度, 所以這是一大球冰淇淋 正被甲蟲在熱草原中運送。 牠並不攀爬也不跳舞, 因為牠身體的溫度是相對較低的, 大約和你我的體溫差不多。 在這裡很有趣的是這小小的頭腦是很涼的。 但如果我們跟熱環境溫度比較, 看看土壤的溫度, 大約是攝氏 55 至 60 度左右。 觀察甲蟲跳舞的頻率, 看看牠的前腿。牠們非常熱。 所以球有一些擋熱的效果, 且甲蟲爬上球和擦臉的行為, 都是在試圖冷卻體溫。 我們認為,這樣亦可避掉它走過的熱沙子。
And what we did then was put little boots on these legs, because this was a way to test if the legs were involved in sensing the temperature of the soil. And if you look over here, with boots they climb onto the ball far less often when they had no boots on. So we described these as cool boots. It was a dental compound that we used to make these boots. And we also cooled down the dung ball, so we were able to put the ball in the fridge, gave them a nice cool dung ball, and they climbed onto that ball far less often than when they had a hot ball. So this is called stilting. It's a thermal behavior that you and I do if we cross the beach, we jump onto a towel, somebody has this towel -- "Sorry, I've jumped onto your towel." -- and then you scuttle across onto somebody else's towel, and that way you don't burn your feet. And that's exactly what the beetles are doing here.
我們在它們的腿上穿上小靴子, 因為這是一個測試腿 是否能感受土壤的溫度。 你們看,穿上靴子後 牠們比較不常爬上球。 所以我們將這稱為冷靴子。 我們用牙醫材料來製作這些靴子。 我們也將糞球冷卻, 我們把球放到冰箱裡,給牠們一個很冷的糞球, 發現牠們爬到球上的次數 遠小於熱球的時候。 所以這叫做跳樁行為。牠是一種熱調試行為 就像你我在海灘上 跳到毛巾上,有人有這毛巾- 「對不起,我跳到您的毛巾。」— 然後再跳到別人的毛巾, 這樣你不會燙傷你的雙腳。 這正是甲蟲在做的。
However, there's one more story I'd like to share with you, and that's this particular species. It's from a genus called Pachysoma. There are 13 species in the genus, and they have a particular behavior that I think you will find interesting. This is a dung beetle. Watch what he's doing. Can you spot the difference? They don't normally go this slowly. It's in slow motion. but it's walking forwards, and it's actually taking a pellet of dry dung with it. This is a different species in the same genus but exactly the same foraging behavior.
我有另一個想跟你們分享的故事。 是這種特別的種類。 牠屬於Pachysoma屬。 這個屬當中有 13 個物種, 且牠們有我認為你們會覺得很有趣的行為。 這是糞甲蟲。看牠在做什麼。 你可以找到不同嗎? 牠們通常不是這麼緩慢。這是慢動作。 牠正在往前走, 且帶著一塊糞便。 這是同一屬的另一個物種, 有著完全相同的的覓食行為。
There's one more interesting aspect of this dung beetle's behavior that we found quite fascinating, and that's that it forages and provisions a nest. So watch this individual here, and what he's trying to do is set up a nest. And he doesn't like this first position, but he comes up with a second position, and about 50 minutes later, that nest is finished, and he heads off to forage and provision at a pile of dry dung pellets. And what I want you to notice is the outward path compared to the homeward path, and compare the two. And by and large, you'll see that the homeward path is far more direct than the outward path. On the outward path, he's always on the lookout for a new blob of dung. On the way home, he knows where home is, and he wants to go straight to it. The important thing here is that this is not a one-way trip, as in most dung beetles. The trip here is repeated back and forth between a provisioning site and a nest site. And watch, you're going to see another South African crime taking place right now. (Laughter) And his neighbor steals one of his dung pellets.
另一個關於這糞甲蟲的行為 讓我們覺得很有趣的是 牠覓食和築巢有特定的規則。 所以看這隻, 牠正在試著築巢。 牠不喜歡這第一個位置, 但牠來到第二個位置, 約 50 分鐘後,巢築完了。 然後牠到一堆 糞便上覓食。 我想要你們注意的是比較 外出和回家這兩條路徑。 總的來說,你會看到,回家的路徑 是遠比外出的路徑直接。 在外出的路徑上, 牠總是在找新的食物來源。 在回家的路上,牠知道家在哪裡, 且牠想要直接回去。 重要的是這不是一次單程旅行, 大多數甲蟲,這趟食物來源 與家裡的旅程是一直被重複的。 看,你會看到另一個 南非犯罪發生。(笑聲) 牠的鄰居偷了牠的一個糞便丸。
So what we're looking at here is a behavior called path integration. And what's taking place is that the beetle has got a home spot, it goes out on a convoluted path looking for food, and then when it finds food, it heads straight home. It knows exactly where its home is. Now there's two ways it could be doing that, and we can test that by displacing the beetle to a new position when it's at the foraging site. If it's using landmarks, it will find its home. If it is using something called path integration, it will not find its home. It will arrive at the wrong spot, and what it's doing here if it's using path integration is it's counting its steps or measuring the distance out in this direction. It knows the bearing home, and it knows it should be in that direction. If you displace it, it ends up in the wrong place. So let's see what happens when we put this beetle to the test with a similar experiment.
所以我們這在理看到的 是一種叫做路徑積分的行為。 甲蟲有一個家, 牠用錯綜複雜的路去尋找食物, 然後當牠找到食物, 牠直接回家。牠明確知道家在哪裡。 有兩種方式可以辦到這個, 我們可以將甲蟲 移到新的位置來研究。 如果牠使用的地標,牠會回得到家。 如果牠使用所謂的路徑積分, 它不會找到牠的家。牠會回道錯誤的地方, 如果牠使用路徑積分 牠會計算在每個方向走過的距離。 牠知道多遠也知道方向。 如果你移動牠,牠會回到錯誤的地方。 那麼讓我們看看當我們這麼做時 會發生什麼事。
So here's our cunning experimenter. He displaces the beetle, and now we have to see what is going to take place. What we've got is a burrow. That's where the forage was. The forage has been displaced to a new position. If he's using landmark orientation, he should be able to find the burrow, because he'll be able to recognize the landmarks around it. If he's using path integration, then it should end up in the wrong spot over here.
所以這裡是我們狡猾的實驗者。 牠移動甲蟲, 現在我們要看看到底發生什麼事。 我們有個巢的位置。那是食物所在。 食物被放到新的位置。 如果牠使用地標, 牠應該能夠找回洞穴, 因為牠能夠辨識牠周圍的地標。 如果牠使用路徑積分, 那麼牠會回到那邊錯的位置。
So let's watch what happens when we put the beetle through the whole test. So there he is there. He's about to head home, and look what happens. Shame. It hasn't a clue. It starts to search for its house in the right distance away from the food, but it is clearly completely lost. So we know now that this animal uses path integration to find its way around, and the callous experimenter leads it top left and leaves it. (Laughter)
讓我們看看當我們在甲蟲上試驗後 發生什麼。 牠在那裡。 牠要回家,如何? 糟糕。 牠完全沒有線索。 牠開始在適當的距離找牠的房子 但牠完全迷失了。 所以我們知道,這種動物使用路徑積分 來找到它的路而我們冷酷無情的實驗者 將它領到左上角離開。(笑聲)
So what we're looking at here are a group of animals that use a compass, and they use the sun as a compass to find their way around, and they have some sort of system for measuring that distance, and we know that these species here actually count the steps. That's what they use as an odometer, a step-counting system, to find their way back home. We don't know yet what dung beetles use.
所以我們看到的是一群使用羅盤的小動物, 牠們利用太陽作為一個指南針 來找路 且牠們有某種 可以測量距離的系統, 我們知道,這些物種在實際上 計算步伐,那是牠們用來作為里程表的系統, 來找到牠們回家的路。 我們還不知道糞甲蟲是使用什麼。
So what have we learned from these animals with a brain that's the size of a grain of rice? Well, we know that they can roll balls in a straight line using celestial cues. We know that the dance behavior is an orientation behavior and it's also a thermoregulation behavior, and we also know that they use a path integration system for finding their way home. So for a small animal dealing with a fairly revolting substance we can actually learn an awful lot from these things doing behaviors that you and I couldn't possibly do. Thank you. (Applause)
所以我們從這些腦袋只有一粒米大小的 動物身上學到什麼? 嗯,我們知道牠們可以在一條直線滾球 使用天體的線索。 我們知道舞蹈行為是取向行為, 也是一種體溫調節的行為, 我們還知道牠們使用路徑積分系統 尋找回家的路。 所以以這樣小的動物要處理這麼令人厭惡的東西, 我們事實上可以從中學習很多, 看到牠做很多你我做不到的行為。 謝謝。(掌聲)