Pressures produced when penguins pooh—calculations on avian defaecation

Abstract

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.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2

References

  1. Ganong WF (1999) Review of medical physiology. Appleton and Lange, Stamford

  2. Jackson S (1992) Do seabird gut sizes and mean retention times reflect adaptation to diet and foraging method? Physiol Zool 65:674–697

    Google Scholar 

  3. King AS (1981) Cloaca. In: King AS, McLelland J (eds) Form and function in birds. Academic, London, pp 63–105

  4. 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 York

  5. Langley LL, Cheraskin E (1958) The physiology of man. McGraw Hill, New York

  6. McLelland J (1981) Digestive system. In: King AS, McLelland J (eds) Form and function in birds. Academic, London, pp 70–181

  7. Najarian S, Niroomand H (2000) Peristaltic transport of a power-law fluid with variable consistency. 12th Conf Europ Soc Biomech, Dublin

  8. Rajagopal KR, Truesdell CA (2000) An introduction to the mechanics of fluids. Springer, Berlin Heidelberg New York

  9. 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 7

  10. Yin FCP, Fung YC (1971) Comparison of theory and experiment in peristaltic transport. J Fluid Mech 47:93–112

    Google Scholar 

Download references

Acknowledgements

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.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Victor Benno Meyer-Rochow.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Meyer-Rochow, V.B., Gal, J. Pressures produced when penguins pooh—calculations on avian defaecation. Polar Biol 27, 56–58 (2003). https://doi.org/10.1007/s00300-003-0563-3

Download citation

Keywords

  • Rectal Muscle
  • Gentoo Penguin
  • Outflow Velocity
  • Maximal Distension
  • Penguin Dropping