||By studying genetic variation of some of primates, researchers can more closely study the effects of deforestation and fragmentation. For this study, mantled howler monkeys (Alouatta palliata) are the primates of choice. The samples used in this study were collected by researchers doing fieldwork in Veracruz and Tabasco, Mexico, and gathered at the University of Utah to be analyzed in the evolutionary genetics lab in the Anthropology Department. Most of the mitochondrial DNA (mtDNA) was obtained noninvasively from feces dropped by the howler monkeys, although a few blood samples are being used that were taken by a veterinarian working in Mexico. After extraction from fecal samples, and replication and sequencing of the mtDNA, the sequences of the different groups were compared. It was found that there was very little variation within groups, but this could be due to the small sample size. The variation between groups was significant. The study was successful in adding to the sampling of d-loop sequences already in existence and in optimizing the conditions for more sequencing in the future. More fecal samples were collected from El Zota Biological Field Station in Costa Rica in the summer of 2014, but until a permit is granted they cannot leave Costa Rica. These new samples will be good to have since they come from an area of largely continuous forest with only minimal occurrences of fragmentation. Once the samples are shipped to the University of Utah they will be added to the sample set as well. In increasing the number of samples available we can better determine if a specific forest fragment is experiencing problems with inbreeding. It is expected that if the primates are suffering from fragmentation, it is likely that other species are as well and further measures should be taken to keep the forest alive and healthy.