For that purpose, the researcher could collect data on numerous fruit characteristics of those species eaten by each of the animal groups. Most fruits will naturally fall into one of the three categories. Discriminant analysis could then be used to determine which variables are the best predictors of whether a fruit will be eaten by birds, primates, or squirrels.
Logistic regression answers the same questions as discriminant analysis.
It is often preferred to discriminate analysis as it is more flexible in its assumptions and types of data that can be analyzed. In DA, the independent variables are the predictors and the dependent variables are the groups. As previously mentioned, DA is usually used to predict membership in naturally occurring groups. Usually, several variables are included in a study to see which ones contribute to the discrimination between groups. One first performs the multivariate test, and, if statistically significant, proceeds to see which of the variables have significantly different means across the groups.