Microsatellite analysis was used to determine the MCM MHC class I haplotype frequencies from 425 feral MCM (850 chromosomes). The seven most frequent haplotypes were designated M1 to M7 and assigned colors (M1, black; M2, red; M3, blue; M4, green; M5, yellow; M6, gray; and M7, purple) throughout the figures for clarification. *We have detected an eighth haplotype by microsatellite analysis in two wild-caught MCMs, as well as a parent and offspring in an independent captive breeding facility. Due to the limited number of individuals with this putative haplotype we were unable to characterize it.