A comparison and critique of different scat-analysis methods for determining carnivore diet
Article first published online: 23 FEB 2011
© 2011 The Authors. Mammal Review© 2011 Mammal Society
Volume 41, Issue 4, pages 294–312, October 2011
How to Cite
KLARE, U., KAMLER, J. F. and MACDONALD, D. W. (2011), A comparison and critique of different scat-analysis methods for determining carnivore diet. Mammal Review, 41: 294–312. doi: 10.1111/j.1365-2907.2011.00183.x
- Issue published online: 6 SEP 2011
- Article first published online: 23 FEB 2011
- Submitted 10 December 2009; returned for revision 9 April 2010; revision accepted 12 July 2010
- biomass calculation;
- black-backed jackal;
- cape fox;
- diet analysis;
- frequency of occurrence
- 1For terrestrial carnivores, scat analysis is the technique most often used to determine diets. Various methods of interpreting scat-analysis data exist; however, little is known about how the choice of method affects the results.
- 2We reviewed 50 scat-analysis papers to assess the range of methods currently used. Furthermore, we used a large data set from cape fox Vulpes chama and black-backed jackal Canis mesomelas scats to compare 11 scat-analysis methods. Techniques tested included five biomass calculation methods, four frequency of occurrence methods, one method that estimated volume in scats, and another that estimated mass of food items in scats.
- 3Frequency of occurrence methods were used in 94% of reviewed papers, and in 50% of papers they were the sole methods used. However, we conclude that frequency of occurrence has the least ecological significance and results can be misleading. Although biomass calculations probably provide the best approximation to true diets, only 23% of reviewed papers used suitable biomass calculation methods when models were available for the study species.
- 4Analysis of fox and jackal scats showed that there were significant differences among methods when calculating percent diet composition and niche breadth. Additionally, dietary overlap between species differed considerably among the methods (range of R0 = 0.29–0.79). We conclude that the choice of method can have a significant impact on the results of dietary analysis, and can lead to very different conclusions about a species' ecology.
- 5The best approximation of the true diet can be obtained by using a biomass calculation model that was developed for the same species, or for a closely related species with a similar food spectrum. When no such model is available, either the volume or mass of diet components in the scats should be used. To document rare food items, frequency of occurrence data could also be given.