The system for uniquely identifying subjects from a target population operates to acquire, process and analyze images to create data which contains indicia sufficient to uniquely identify an individual in a population of interest. This system implements an automated, image-based process that captures data indicative of a selected set of external characteristics for subjects that are members of a target population of a predetermined species. The captured data is then processed to create a database record which is associated with the selected subject and which can be used to uniquely identify the selected subject. The subject identification process is repeatable, so any subject can be accurately mapped to their associated database record, which database record can be updated to reflect changes in the subject.