Pressures produced when penguins pooh—calculations on avian defaecation
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Chinstrap and Adélie penguins generate considerable pressures to propel their faeces away from the edge of the nest. The pressures involved can be approximated if the following parameters are known: (1) distance the faecal 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. With all of these parameters measured, we calculated that fully grown penguins generate pressures of around 10 kPa (77 mm Hg) to expel watery material and 60 kPa (450 mm Hg) to expel material of higher viscosity similar to that of olive oil. The forces involved, lying well above those known for humans, are high, but do not lead to an energetically wasteful turbulent flow. Whether a bird chooses the direction into which it decides to expel its faeces, and what role the wind plays in this, remain unknown.
We wish to thank Dr. Sören Scheid (Institut fur Umweltverfahrenstechnik, Universität Bremen, Germany) for his assistance with the viscosity measurements, and the New Zealand University Grants Committee, as well as the Chilean Antarctic Program (INACH), the last for their support of the first Jamaican Expedition to Antarctica.
- Ganong WF (1999) Review of medical physiology. Appleton and Lange, StamfordGoogle Scholar
- Jackson S (1992) Do seabird gut sizes and mean retention times reflect adaptation to diet and foraging method? Physiol Zool 65:674–697Google Scholar
- King AS (1981) Cloaca. In: King AS, McLelland J (eds) Form and function in birds. Academic, London, pp 63–105Google Scholar
- Landolt H, Börnstein R (1955) Material values and mechanical behavior of non-metals. In: Schmidt E (ed) Numerical data and functional relationships in science and technology, vol IV/1. Springer, Berlin Heidelberg New YorkGoogle Scholar
- Langley LL, Cheraskin E (1958) The physiology of man. McGraw Hill, New YorkGoogle Scholar
- McLelland J (1981) Digestive system. In: King AS, McLelland J (eds) Form and function in birds. Academic, London, pp 70–181Google Scholar
- Najarian S, Niroomand H (2000) Peristaltic transport of a power-law fluid with variable consistency. 12th Conf Europ Soc Biomech, DublinGoogle Scholar
- Rajagopal KR, Truesdell CA (2000) An introduction to the mechanics of fluids. Springer, Berlin Heidelberg New YorkGoogle Scholar
- Watson M (1883) Report on the anatomy of the Spheniscidae collected during the voyage of H.M.S. Challenger. Report on the Scientific Results of the Voyage of H.M.S. Challenger (Zoology), vol 7Google Scholar
- Yin FCP, Fung YC (1971) Comparison of theory and experiment in peristaltic transport. J Fluid Mech 47:93–112Google Scholar