Humans tend to think of animal species as being composed of individuals with identical habitat requirements and food preferences.  In fact, many foundational theories in behavioral ecology assume that all members of a population behave in the same manner.  This is a result of how most wildlife studies are conducted.  It is often difficult to identify individual animals in the wild, so most studies of foraging ecology and habitat selection are conducted at the level of the population (aggregating all observations of animals rather than investigating how specific individuals behave).  The problem with this approach is that if the assumption of all animals behaving similarly is incorrect, then the investigator may reach erroneous conclusions.  If individuals within a population are habitat specialists but there are differences among them regarding the specific resources that they select, then population-level studies may lead to erroneous conclusions that all members of the population are habitat generalists.
     Because the Sarasota Dolphin Research Program has been conducting photographic identification studies of bottlenose dolphins in Sarasota Bay for over 37 years, we are uniquely positioned to investigate how the results of habitat selection studies might differ depending on whether the population or individual approach is used.  In conjunction with our studies of the distribution and abundance of dolphin prey fish, we have developed detailed classifications of habitats within Sarasota Bay, and can quantify the ranging patterns of resident dolphins relative to habitat features using GIS technology.
     We have found that at the level of the population, dolphins did not use any habitat type disproportionately to its availability (meaning that as a group, the dolphins showed no preference for any particular habitat).  In contrast, individual dolphins exhibited strong habitat selection, and there were differences among individuals regarding the specific habitats that they chose to use within the community range.  Furthermore, patterns of habitat selection may be related to age, sex, reproductive condition, and maternal lineage.  Therefore, this appears to be a generalist population composed of individual specialists.  Differences in habitat selection likely reflect differences in prey preferences, foraging strategies, nutritional requirements, and/or social status.  Attempting to manage bottlenose dolphin populations (or those of any species) without a proper understanding of individual variation in habitat selection may leave some elements of the population at risk.  Support for this work has come primarily from NOAA’s Fisheries Service.