A Critical Review of Zoo-based Olfactory Enrichment

  • Fay Clark
  • Andrew J. King


Olfactory stimuli are frequently integrated into zoo enrichment programs. This ‘olfactory enrichment’ can stimulate reproduction or naturalistic behaviour, enhance enclosure exploration, or reduce inactivity. However, not all scents achieve their desired goals, and can in fact bring about undesirable behaviour such as increased levels of stereotypy. Few attempts have been made to quantify the impact of introducing olfactory stimuli to zoo enclosures, and there are inherent difficulties when designing, implementing and evaluating olfactory enrichment. Firstly, it is difficult without appropriate chemical analyses to anticipate what information a scent conveys, and therefore whether it will be received as an excitatory or aversive stimulant. Second, more practical difficulties are encountered. Consideration needs to be given to (i) the choice of scent used, its relevance and motivation, (ii) how to present the scent in time and space, (iii) individual variation in response rates and neophobia (fear of novelty) to scents, and finally (iv) the health implications linked to the use of olfactory stimuli. This paper reviews the olfactory stimuli used in zoos as enrichments and their reported effects. Practical suggestions are made to encourage and stimulate more empirical quantification of olfactory stimulation in zoo animals.


Environmental Enrichment Olfactory Stimulus Scent Mark Captive Animal Captive Chimpanzee 
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  1. Baker, W.K. Jr., Campbell, R. and Gilbert, J. (1997) Enriching the pride: scents that make sense. The Shape of Enrichment 6, 1–3.Google Scholar
  2. Boon, M. (2003) Goeldi’s monkeys (Callimico goeldii): olfactory enrichment to stimulate natural behaviour and greater activity. In: T. Gilbert (Ed.), Proceedings of the 5 th Annual Symposium on Zoo Research, Marwell Zoo, pp. 212–224.Google Scholar
  3. Breazile, J.E. (1987) Physiological basis and consequences of distress in animals. J. Am. Vet. Med. Assoc. 191, 1212–1215.PubMedGoogle Scholar
  4. Buchanan-Smith, H.M., Anderson, D.A. and Ryan, C.W. (1993) Responses of cotton-top tamarins (Saguinus oedipus) to faecal scents of predators and non-predators. Anim. Welf. 2, 17–32.Google Scholar
  5. Burr, L.E. (1997) Reptile enrichment: scenting for a response. Animal Keepers Forum. 24, 122–23.Google Scholar
  6. Burrell, K., Wehnelt, S. and Rowland, H. (2004) The effect of whole carcass feeding and novel scent on jaguars (Panthera onca) at Chester Zoo. British and Irish Association of Zoos and Aquariums Zoo Federation Research Newsletter 5, 4.Google Scholar
  7. Calderisi, D. (1997) Different scents for different responses in predator-prey relationships as a form of enrichment in captive animals. In: V. Hare and K. Worley (Eds.), Proceedings of the Third International Conference on Environmental Enrichment, Sea World, Florida, pp. 155–161.Google Scholar
  8. Carlstead, K. (1996) Effects of captivity on the behavior of wild mammals. In: D. G. Kleiman, M. E. Allen, K. V. Thomson and S. Lumpkin (Eds.), Wild Mammals in Captivity: Principles and Techniques, University of Chicago Press: Chicago, pp. 317–333.Google Scholar
  9. Chamove, A.S. (1989) Environmental enrichment: a review. Anim. Tech. 40, 155–79.Google Scholar
  10. Clark, F. (2004) Olfactory enrichment for the captive jaguar (Panthera onca). Unpublished BSc. thesis, University of Southampton.Google Scholar
  11. Clark, F., Melfi, V. and Mitchell, H. (2005) Wake up and smell the enrichment: a critical review of an olfactory enrichment study. In: N. Clum, S. Silver and P. Thomas (Eds.), Proceedings of the Seventh International Conference on Environmental Enrichment, Wildlife Conservation Society, New York City, pp. 178–185.Google Scholar
  12. Eisenberg, J.F. and Kleiman, D.G. (1972) Olfactory communication in mammals. Ann. Rev. Ecol. Syst. 3, 1–32.CrossRefGoogle Scholar
  13. Engel, C. (2002) Wild health: how animals keep themselves well and what we can learn from them. Houghton Mifflin, Boston.Google Scholar
  14. Foss, T.S. (2002) Liquid potpourri and cats - Essence of Trouble. Vet. Tech. 23, 686–689.Google Scholar
  15. Hancox, M. (1990) Smell as a factor is mammalian behaviour. Int. Zoo News. 224, 19–20.Google Scholar
  16. Halpin, Z.T. (1986) Individual odors among mammals: origins and functions. Adv. Study Behav. 16, 39–70.CrossRefGoogle Scholar
  17. Hawkins, M. (1997) Effects of Olfactory Enrichment on Australian Marsupial Species. In: V. Hare and K.Worley (Eds)., Proceedings of the Third International Conference on Environmental Enrichment, Sea World, Florida, pp. 135–149.Google Scholar
  18. Hayes, M.P., Jennings, M.R. and Mellen, J.D. (1998) Beyond mammals: environmental enrichment for amphibians & reptiles. In: Shepherdson, D.J., Mellen, J.D. and Hutchins, M. (Eds) Second Nature: Environmental Enrichment for Captive Animals. Smithsonian Institute Press, Washington, pp. 205–235.Google Scholar
  19. Hill, J.O., Pavlik, E.J., Smith, G.L., Burghardt, G.M and Coulson, P.B. (1976) Species-characteristic responses to catnip by undomesticated felids. J. Chem. Ecol. 2, 239–253.CrossRefGoogle Scholar
  20. Kitchener, A. (1991) The Natural History of the Wild Cats. Comstock, New York.Google Scholar
  21. Kleiman, D.G., Allen, M.E., Thompson, K.V. and Lumpkin, S. (1998) Wild Animals in Captivity: Principles and Techniques. University of Chicago Press.Google Scholar
  22. Knight K. (2004) Does the presence of a novel olfactory stimulus affect the behaviour of captive Jaguars (Panthera onca): implications for enrichment. Unpublished BSc. thesis, Liverpool John Moores University.Google Scholar
  23. Leach, M., Young, R. and Waran, N. (1998) Olfactory enrichment for Asian elephants: is it as effective as it smells? Int. Zoo News 54 (5): 285–290.Google Scholar
  24. Leyhausen, P. (1979) Cat Behaviour: The Predatory and Social Behaviour of Domestic and Wild Cats. Garland Press, New York.Google Scholar
  25. Mason, G.J. (1991) Stereotypies and suffering. Behav. Process. 25, 103–115.CrossRefGoogle Scholar
  26. McCusker, C. and Smith, T.E. (2002) The potential of biologically relevant odour cues to function as a novel form of enrichment in captive ring-tailed lemurs, Lemur catta. British and Irish Association of Zoos and Aquariums Federation Research Newsletter 3, 3.Google Scholar
  27. Melfi, V., Plowman, A., Knowles, L. and Roynon, J. (2007) Constructing an environmental enrichment programme with minimal habituation: a case study using Sumatran tigers. Unpublished manuscript.Google Scholar
  28. Mellen, J. (1993) A comparative analysis of scent-marking, social and reproductive behaviour in twenty species of small cats (Felis). Am. Zool. 33, 151–166.Google Scholar
  29. Moodie, E.M., and Chamove, A.S. (1990) Brief threatening events beneficial for captive tamarins? Zoo. Bio. 9, 275–286.CrossRefGoogle Scholar
  30. Newberry, R.C. (1995) Environmental enrichment: increasing the biological relevance of captive environments. Appl. Anim. Behav. Sci. 44, 229–244.CrossRefGoogle Scholar
  31. Noonan, B. (1999) Enrichment for African lions. The Shape of Enrichment 8, 6–7.Google Scholar
  32. Ostrower, S. and Brent, L. (1997) Olfactory enrichment for captive chimpanzees: responses to different odours. Laboratory primate newsletter 36, 8–10.Google Scholar
  33. Powell, D.M. (1995) Preliminary investigation of environmental enrichment techniques for African lions (Panthera leo). Anim. Welf. 4, 361–70.Google Scholar
  34. Renner, M.J. and Lussier, J.P. (2002) Environmental Enrichment for the captive spectacled bear (Tremarctos ornatus). Pharmacol. Biochem. Behav. 73, 279–283.PubMedCrossRefGoogle Scholar
  35. Richardson, J.A. (1999) Potpourri hazards in cats. Vet. Med. 94, 1010–1012.Google Scholar
  36. Robinson, M.H. (1998) Enriching the lives of zoo animals, and their welfare: where research can be fundamental. Anim. Welf. 7, 151–175.Google Scholar
  37. Saibaba, P., Sales, G.D., Stodulski, G. and Hau, J. (1996) Behaviour of rats in their home cages: daytime variations and effects of routine husbandry procedures analysed by time sampling techniques. Lab. Anim. 30, 13–21.PubMedCrossRefGoogle Scholar
  38. Schaap, D. (2002) Enriching the Devil: The Tasmanian Devil. The Shape of Enrichment. 11, 1–4.Google Scholar
  39. Schuett, E.B. and Frase, B.A. (2001) Making scents: using the olfactory senses for lion enrichment. The Shape of Enrichment. 10, 1–3.Google Scholar
  40. Shepherdson, D. (1989) Stereotypic behaviour: what is it and how can it be eliminated or prevented? Journal of the Association of British Wild Animal Keepers. 16, 100–5.Google Scholar
  41. Sommerville, B.A. and Broom, D.M. (1998) Olfactory awareness. Appl. Anim. Behav. Sci. 57, 269–286.CrossRefGoogle Scholar
  42. Spielman, J.S (2000) Olfactory enrichment for captive tigers (Panthera tigris) and lions (Panthera leo), using a synthetic analogue of feline facial pheromone. Unpublished MSc. thesis, University of Edinburgh.Google Scholar
  43. Struthers, E. J. and Campbell, J. (1996) Scent-specific behavioral response to olfactory enrichment in captive chimpanzees (Pan troglodytes). Presented at the XVIth Congress of the International Primatological Society and the XIXth Conference of the American Society of Primatology, Wisconsin.Google Scholar
  44. Swaisgood, R.R. and Shepherdson, D.J. (2005) Scientific approaches to enrichment and stereotypies in zoo animals: what’s been done and where should we go next? Zoo. Biol. 24, 499–518.CrossRefGoogle Scholar
  45. Testa, D. (1997) Paws to play: enrichment ideas for lynxes. The Shape of Enrichment. 6, 1–2.Google Scholar
  46. Todd, N.B. (1963) The catnip response. Unpublished PhD. thesis, Harvard University.Google Scholar
  47. Trager, G.C. and Germanton, H. (1997) Coatimundis enrich their own lives in nature by putting on the perfume, so why not let them do it in captivity? In: V. Hare and K.Worley (Eds.), Proceedings of the Third International Conference on Environmental Enrichment, Sea World, Florida, pp. 150–154.Google Scholar
  48. Van Loo, P.L.P., Kruitwagen, C.L.J.J., Van Zutphen, L.F.M., Koolhaas, V. and Baumans, V. (2000) Modulation of aggression in male mice: influence of cage cleaning regime and scent marks. Anim. Welf. 9, 281–295.Google Scholar
  49. Wells, D.L. and Egli, J.M. (2004) The influence of olfactory enrichment on the behaviour of black-footed cats, Felis nigripes. Appl. Anim. Behav. Sci. 85, 107–119.CrossRefGoogle Scholar
  50. Williams, N., Chapman, J., and Plowman, A. (1999) Olfactory enrichment for big cats, Panthera leo persica and Panthera tigris sumatrae. In: V. Hare and K.Worley (Eds.), Proceedings of the Fourth International Conference on Environmental Enrichment, Edinburgh Zoo, Edinburgh, pp. 300–303.Google Scholar
  51. Young, R.J. (2003) Environmental enrichment for captive animals. Blackwell Science Publishing, Oxford.Google Scholar

Copyright information

© Springer Science+Business Media,LLC 2008

Authors and Affiliations

  • Fay Clark
    • 1
  • Andrew J. King
  1. 1.Institute of Zoology,Zoological Society of LondonLondonUK

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