Retrospectacle: A Neuroscience Blog

[This is part of a series I'm doing here on Retrospectacle called 'Science Vault.' Pretty much I'm just going to dig back into the forgotten and moldering annuls of scientific publications to find weird and interesting studies that very likely would never be published or done today (and perhaps never should have.) I'll probably try to do it once a week (and if you have suggestions, please do email me with them.)]

i-11c1e33d77ff4f42cab3400488a9afb6-penguin 1.jpgFor this weeks ‘Science Vault, I didn’t really have to reach too far back in time to find something utterly ridiculous and slightly ribald. Nay dear reader, in 2003 the journal Polar Biology published a gem of a paper entitled ‘Pressures produced when penguins pooh–calculations on avian defecation.’ (pdf) by Benno et al. Apparently, a few types of penguins are naturally endowed with the special ability of not crapping in their nests. That is, they have sufficient…er…..gastrointestinal pressures (snicker snicker) to…uh….propel their poop away from them. Obviously, the distance and trajectory of this unique penguin pooping should be measured and documented, then published for the good of all mankind!

(Read on for all the explosive details…..)

Now, from the author’s mouths:

The pressures involved [in the projectile pooping] can be approximated if the following parameters are known: (1) distance the fecal material travels before it hits the ground, (2) density and viscosity of the material, and (3) shape, aperture, and height above the ground of the orificium venti.

So, the goal was to estimate what the force of the “pressure” was by observing the physics of the pooping process and the characteristics of the poop itself and of the [shudder] orifice involved.

Now, what exactly are we talking about here? Well if you need visual confirmation of this (now) well-documented phenomena, why just cast thine eyes downward to this rare YouTube footage.

During the brooding season, when penguins are sitting on their nests, they don’t want to leave their nests and thereby leaving their eggs open to predation. This would make for an uncomfortable situation when nature called, so they evolved the ability to poop without ever leaving the nest. The bird moves to the edge of the nest, lifts their tail, and “shoots.”

The authors observed these penguins “in the act,” and are meticulous in their pooply descriptions:

The expelled material hits the ground maximally 40±12 cm away from the bird and then leaves behind a whitish or pinkish streak that can end a few centimetres from the nest s periphery and may be up to 1 cm wide. The colour of the streak depends on whether the penguin had enjoyed a meal of fish (mostly white) or krill (pinkish). According to Jackson (1992), the time required to excrete 50% of the total faecal mass is 9.1 h and 14.5 h for fish and prawn food, respectively.

They estimated that the orifice had a maximum diameter of 8 mm “at the moment of firing,” (ew) and that the penguin’s rear was around 20 +/- 6 cm above the ground. They used this data to infer the pressure required to achieve the distance that the poop had traveled from the nest. For clarification, please refer to the helpful figure below.

i-5617f714c6da0057fc8364ad30c435ce-penguin poop 1.bmp

Using the Hagan-Poiseuille-equation for dynamic pressure, they determined that the pressure needed to project the poop depended on the viscosity of said poop. Observe Figure 2 (below), which illustrates the dependence of pooping pressure on viscosity.

i-b0611977f391521b583dd6adbc043ece-penguin poop 2.bmp

This necessitated that the authors measure the penguin poop’s viscosity with a high-performance viscosimeter (not one of those cheap-o low-performance viscosimeters!). However, the readings were inconsistent due to all the fishbones and shrimp shells in the poop, but their best estimate was that the poop’s viscosity matched somewhere around that of olive oil. (Ew ew.) After this final value was obtained, they were able to complete the equation and estimate that the power of a penguin’s fart was somewhere in the range of 10kPa to 60 kPa. Bravo.

And just in case you wondered what this meant for humans, well, the authors covered that in the discussion.

The pressures on the rectal muscles in an upright human amount to 20 mmHg and are resisted by the rectal muscles, but when pressures reach 55 mmHg, the external as well as the internal sphincter relaxes and the contents of the rectum are expelled (Ganong 1999). During straining, pressures may rise well above 100 mmHg (Langley and Cheraskin 1958), but it would seem that the pressures regularly produced by penguins to expel their faeces on land are considerably greater, possibly reaching half an atmosphere.

Yeah, thats right. Penguins can fart better than us. Birds rule.

Comments

  1. #1 Romeo Vitelli
    July 7, 2007

    I wonder what Freud would have made of this? Being anal retentive would definitely be a drawback for a penguin.

  2. #2 Steve h
    July 7, 2007

    i love the guys in the video. hah…

  3. #3 Richard Gay
    July 7, 2007

    Shelley, the following text of yours:

    ‘During the brooding season, when penguins are sitting on their nests, they don’t want to leave their nests and thereby leaving their eggs open to predation. This would make for an uncomfortable situation when nature called, so they evolved the ability to poop without ever leaving the nest. The bird moves to the edge of the nest, lifts their tail, and “shoots.”‘

    …is problematic in that it depicts evolution as a voluntary event, whereas I believe your statement should be more along the lines of

    ‘these particular penguin species have been naturally selected for the projectile-pooping ability, which allows them to defecate without leaving their nests, providing them an opportunity to greater protect their nests in brooding season.’

    I think it’s important not to portray evolution as some kind of organism-directed process.

    SB: Well, I certainly meant it as the second. If penguins could direct their own evolution AND projectile poop…..

  4. #4 Ed Yong
    July 7, 2007

    Is there no limit to where science is prepared to go?? What if this discovery falls into the wrong hands? What if someone weaponises the penguins? Their cute, hapless looks will lure us into a false sense of security as their handlers bombard us with high-velocity pellets. Fear the penguins!

  5. #5 Chris
    July 7, 2007

    Ya know, it’s been a great morning. I wake up, feeling great, have good cup of coffee, sit down at my computer to see what’s happening in Shelley’s world… and then it all goes downhill from there.

    Just kidding.

    That’s an Ignoble candidate for sure.

    I am fairly sure that it is not unheard of that some birds can projectile poop in self defense. I think I’ll go look it up.

  6. #6 Gork
    July 7, 2007

    I never thought I’d live to see a penguin expressing a political opinion.

  7. #7 Markus
    July 7, 2007

    Chris,

    actually, it is not a candidate for the IG – it is actually a IG winner.

    FLUID DYNAMICS: Victor Benno Meyer-Rochow of International University Bremen, Germany and the University of Oulu, Finland; and Jozsef Gal of Loránd Eötvös University, Hungary, for using basic principles of physics to calculate the pressure that builds up inside a penguin, as detailed in their report “Pressures Produced When Penguins Pooh — Calculations on Avian Defaecation.”
    PUBLISHED IN: Polar Biology, vol. 27, 2003, pp. 56-8.
    ACCEPTING: The winners were unable to attend the ceremony because they could not obtain United States visas to visit the United States. Dr. Meyer-Rochow sent an acceptance speech via video.

    http://www.improbable.com/ig-pastwinners.html#ig2005

  8. #8 Stephen D. Moore
    July 8, 2007

    Ed Yong writes:

    What if someone weaponises the penguins? Their cute, hapless looks will lure us into a false sense of security as their handlers bombard us with high-velocity pellets. Fear the penguins!

    Markus writes:

    The winners [of the IgNobel] were unable to attend the ceremony because they could not obtain United States visas to visit the United States.

    Wow! The Dept. of Homeland Security was on the ball this time.

  9. #9 jvarisco
    July 8, 2007

    I realize the penguins’ home must be pretty depressing, but surely you mean the breeding season?

  10. #10 Hypatia
    July 8, 2007

    Ospreys are pretty adept at projectile pooping. They are abundant where I live in west coastal Florida, and a pair resides year-round very near where I work. Judging by the lime circles under the light poles where they perch, one would be well-advised to give them a wide berth–5 meters at minimum–when walking past one of these beauties loafing above the parking lot.

  11. #11 Caledonian
    July 14, 2007

    No, brooding – as in “maintaining eggs on a nest”.

  12. #12 Mark
    February 21, 2012

    It would be impossible making this kind of research in Italy. We are stopped at stoneage unfortunatly. Sigh!

  13. #13 Mark
    February 21, 2012

    It would it be wonderful making this kind of research in Italy, but we are stopped at stonage, unfortunatly. Sigh!