Penguin Pooing Pressure, Calculated Anew

The penguin pooing pressure calculation that won the 2005 Ig Nobel Prize for fluid dynamics has been calculated anew by a different group of scientists.

The new study is: “Projectile Trajectory of Penguin’s Faeces and Rectal Pressure Revisited,” Hiroyuki Tajima and Fumiya Fujisawa, arXiv 2007.00926v1, 2020. The authors, at Kochi University and at the Katsurahama Aquarium, Japan, report:

We discuss a trajectory of penguins’ faeces after the powerful shooting due to their strong rectal pressure…. We estimate the upper bound for the maximum flight distance by solving the Newton’s equation of motion…. In the presence of the viscous resistance, the grounding time and the flying distance of faeces can be expressed in terms of Lambert W function. Furthermore, we address the penguin’s rectal pressure within the hydrodynamical approximation combining Bernoulli’s theorem and Hagen-Poiseuille equation for viscosity corrections. We found that the calculated rectal pressure is larger than the estimation in the previous work….

In the pioneering work of Reference [2], it is reported that this actual pressure could range from 10 kPa for relevant values of the faeces viscosity and the radius of the the bottom hole.

A Look Back at the Pioneering Early Work, and at the Pioneer

That 2005 Ig Nobel Prize was awarded to 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 the journal Polar Biology, vol. 27, 2003, pp. 56-8). Here is a technical drawing from that original penguin poo pressure paper:

Meyer-Rochow has discussed why he undertook the question.

And by happy coincidence, this week the ICES Journal of Marine Science published his invited biographical essay “Ingredients to become a scientist: curiosity, enthusiasm, perseverance, opportunity, and a good pinch of luck.” The essay is filled with adventures, of which here is a tiny sample:

a personal highlight was the first (and only) Jamaican Antarctic Expedition with my assistant Walton Reid in 1993 (which led me to be introduced to Queen Elizabeth II when she visited the University of the West Indies in Kingston, Jamaica). When asked by “The Queen” if it hadn’t been very cold in Antarctica and she inquired about how our work had benefitted society, I replied that, of course, it had been a little cold at times and regarding our results, they had made the “book of human knowledge” just a tiny bit thicker (I am not a believer that all research must immediately be seen to be applied).

You have really got to keep your eyes open and retain a childish curiosity (curiosity may kill the cat, but for a scientist it is an essential ingredient: another piece of advice) and, when I saw (and photographed) pooping penguins, I immediately wondered about the pressure that these not exactly tall birds generate to propel their faeces up to 50 cm away from their nest’s edge. The research on this immensely important aspect of penguin biology, conducted with my research assistant Dr Joseph Gal, led to an Ig- Nobel prize from Harvard University, which quite honestly was very helpful to me in Japan and many other countries (as I, erroneously, was often announced to the audience as a “Nobel prize winner”—well, of sorts).