The Use of Photography to Identify Individual Tree Frogs by Their Natural Marks

Many research questions require the recognition and permanent identification of individual organisms. The use of photography for this identification from their natural marks is a non-invasive technique that can be applied to species with variable color patterns. The goals of this study were to describe the method of photographic identification by natural marks of individuals of Scinax longilineus and to test the feasibility of implementing this method in field research. Fieldwork was conducted in April, May, and August 2006, April 2007 and May 2008. Individuals were collected, photographed, and released at the same location, except for two pairs that were taken to the laboratory and preserved after identification experiments. In the laboratory, observers were selected to compare the photographs, which were organized in a database, with live animals in order to test the ease and accuracy of recognition of individuals from natural marks. Twenty-four males and 44 females were photographed, generating a database of 156 photographs. Tests conducted with observers had a high percentage of correct answers (93.75% for tests with photographs and 92.5% for tests with live animals) and no difference between the efficacy of the two identification methods was detected.