Discrimination between cat and dog hairs using numerical morphology

Abstract

Cats and dogs are universal pets that can be easily found in Malaysia. Due to the constant hair loss, a lot of cat and dog hairs are encountered in the household, their surroundings and adhere onto clothing or the body of the owner or anyone came into contact without being noticed. These hairs are sometimes the only available evidence found at crime scene. In this study, hair samples from seven types of cats and thirteen types of dog breeds were collected. Difference between two species was analyzed using three types of microscope; compound microscope, stereomicroscope, and scanning electron microscope. Numerical morphology employ six measurements on hair samples which are (length, (Len), maximum width (MaxWid), medulla width (MedWid), width at 1/3 of proximal hair shaft (proWid), medullary index (MI) and hair width index (HWI). The statistical tests of t-test and f-test show significant differences between cat and dog hairs based on Len, MaxWid and MI. In this study, morphology features examination between several other animals from different animal species found in Malaysia were also carried out. Result of the study showed unique morphologies based on cuticle pattern and medulla characteristics. Outcome of this research has provides a standard reference of morphology features that could help forensic scientist to identify the species origin of unknown hair samples frequently obtained as exhibit in the Malaysian Forensic Laboratory.