Morphological and Morphometric Characteristics of Brown Rat (Rattus Norvegicus) in Tehran and Mashhad

The purpose of this study was to investigate the morphological and morphometric characteristics of brown rats in Tehran and Mashhad. To investigate these characteristics, 75 brown rats from Tehran and Mashhad were rehabilitated using trapping and compared based on morphological and morphometric studies and the characteristics of each index were identified. The results of this research showed that the dorsal and ventral colors of Mashhad rats were brighter than Tehran rats. Also, the ratio of body length to ear length of males was higher in population of Mashhad rats. However, the ratio of body length to ear length of females was higher in population of Tehran rats. Univariate analysis of variance showed that among 49 measured cranial morphometric traits, maxillary frontal width, terminal skull length, upper first premolar width, lower second premolar length, had good differentiation power for the two populations of Tehran and Mashhad and the other traits had a weak differentiation power. Also, most of the differentiation powers were related to the second premolar tooth length. No differences were observed between the five populations for the five morphometric traits. There was also a gender bias between males and females.