Exploring the dynamics of human scent in forensic canine analysis: Factors shaping identification accuracy

Abstract

Using specially trained canines in forensic analysis to identify individual human scents is a well-established method, capitalizing on dogs' exceptional olfactory abilities. This study investigates the survival of human scent under extreme weather conditions in the Kingdom of Bahrain. Five experienced German Shepherd police dogs, trained for human scent tracking, participated in the experiments. The study was conducted during Bahrain's hot summer season, characterized by high temperatures, high humidity, and occasional strong winds. Three common surfaces—sand, grass, and asphalt—were selected to represent scenarios where human scent might be detected.

The findings revealed that human scent persisted for approximately 8–11 hours on sand and grass but only 1–3 hours on asphalt, highlighting the impact of surface type on scent survival. The research also examined the effect of temperature on scent survival, testing at three different temperatures: 30°C, 40°C, and 50°C. The results demonstrated that scent durability varied across types of articles and temperature conditions. For instance, at 30°C, human scent remained detectable for up to 93 days on leather but only 27–28 days on silk cloth. At 40°C, leather allowed the scent to last 64–65 days, while wood surfaces had the shortest duration. The scent lasted 37–39 days on jeans cloth at a temperature of 50°C but only 3–4 days on wood. The data gathered can be beneficial for forensic investigations in semi-desert areas involving canine olfaction, offering guidance on the timing and likelihood of scent detection.