A method for discriminating between heated and non-heated fish bones is based on the morphological changes of fish bone collagen during thermal and hydrothermal denaturation. Controlled heating of samples of modern fish bones from 60 to 100 ° C were performed. The morphological changes of collagen have been found to increase with temperature. The method might be used to demonstrate subfossil meal remnants and could be a possible means to separate naturally deposited fish bones from human refuse. -- AATA