Unique metabolic and physiological adaptations underlying the evolution and radiation of snakes make them an excellent evolutionary model. Since snakes with coloration and band patterns similar to coral snakes provide an evident selective advantage over non-mimetic snakes, our aim was to evaluate this evolutionary process from a comparative genomic perspective. We were able to provide evidence of selective pressures on mitochondrial genes related to an evolutionary adaptation to mimicry in snakes of the genus Erythrolamprus. Our results suggest a pattern of differential nucleotide composition and codon bias in the genus Erythrolamprus over other species of the family Dipsadidae. We found that all mitochondrial genomes in the family are under selection pressure, however, we were able to determine that mimic species possess in some mitochondrial genes have higher magnitude of selective pressure. This study proposes a method to study the different patterns of features in the mitogenomes of closely related species, besides evidencing the selective pressures of a complex process such as mimicry.