European otter (Lutra lutra) scent marks (spraint and anal sac secretion material) from captive and wild animals were analysed using solvent extraction and solid phase micro extraction (SPME). An ageing study (using SPME) mapped spraint chemical composition changes following deposition and how low temperature storage and exposure to the environment affected these changes. Chemicals with opposite time dependence were found; providing a possible spraint ageing mechanism. Temperature and environmental conditions affected the rates of production and deterioration of these chemicals and therefore the accuracy of spraint age estimations. Identification of the fatty acid content of otter scent marking material from 4 otter species led to both intra-specific (L.lutra) and inter-specific (Canadian river, Lontra canadensis; Asian short claw, Aonyx cinerea; and Giant, Pteronura brasiliensis) comparisons. Low volatility fatty acids (C10-C24.1) were found in all scent mark types. Intra-specifically, differentiation was seen in spraint fatty acid profiles based on sexual identity. Differentiation was observed between L. lutra scent marking material types (Captive spraint; Wild spraint; Wild anal sac secretion). Inter-specific differences relied on a mixture of ‘digital’ and ‘analogue’ coding. SPME and gas chromatography – mass spectrometry (GCMS) were used to investigate intra- (L.lutra) and inter- specific (L. lutra, A. cinerea, L. canadensis, and badger, Meles meles) differences in the headspace chemicals of otter scent marks. Inter-sanctuary (possibly diet related) differences in spraint odour of L. lutra were seen. No overall male - female differences were found, although possible intra-sanctuary sexual differences were seen. Inter-specific differentiation in scent mark odour profiles due to a combination of both analogue and digital coding elements was observed.