The study of mammalian diversity in the Gurupi started in December 2000, and includes the Gurupi Biological Reserve and adjacent Indigenous Reservations (Caru and Alto Turiaçu). This work is focused on the evaluation of problems related to the conservation of the area, which is one of the last remnants of the Amazon forest in Maranhão, the state with the worst rates of deforestation throughout the Amazon region (<30% of the original cover). The Amazon forest which once covered the state of Maranhão, today only exists in Gurupi. Preliminary results from our study indicated the presence of at least 63 species of mammals, not including bats and this number is likely to increase with further studies of small mammal communities. This number is representative when compared to other Amazon regions. The area is of the highest conservation importance because it has 11 mammal species threatened with extinction. These include the Kaapori Capuchin (Cebus Kaapori) considered by the new list of endangered Brazilian species as critically endangered, which means that it can become extinct very quickly. Another monkey, the black-bearded saki (Chiropotes satanas) is also critically endangered. Both species have Gurupi as their main area of occurrence, which means that if the area is further degraded by logging and cleared for cattle pasture, the two species will become extinct.

The fauna of carnivores in the region is diverse, with 14 species, seven of which are on the new list of IBAMA. These animals, even though in theoretically protected areas suffer persecution, especially the big cats: the jaguar and the puma. This is because these animals sometimes prey on livestock in the farms located within the Biological Reserve. The Gurupi also home to the last populations of giant otters in Maranhão. Also present are bush dogs (Speothos venaticus), neotropical otter, grison, raccoon and other species of cats.

Another point of vital importance is the fact that the region is also home to the Awá-Guajás, a semi-nomadic people who live largely as their ancestors lived and who are also threatened with extinction by the greed of loggers, ranchers and others, who invaded their land in search of timber, hunting, supplies for the pharmaceutical industry, and pasture for livestock (including buffalo). This ethnic group that is found only in the region of Gurupi has a population of 250 individuals.

The study of mammalian diversity in the Gurupi started in December 2000, and includes the Gurupi Biological Reserve and adjacent Indigenous Reservations (Caru and Alto Turiaçu). This work is focused on the evaluation of problems related to the conservation of the area, which is one of the last remnants of the Amazon forest in Maranhão, the state with the worst rates of deforestation throughout the Amazon region (<30% of the original cover). The Amazon forest which once covered the state of Maranhão, today only exists in Gurupi. Preliminary results from our study indicated the presence of at least 63 species of mammals, not including bats and this number is likely to increase with further studies of small mammal communities. This number is representative when compared to other Amazon regions. The area is of the highest conservation importance because it has 11 mammal species threatened with extinction. These include the Kaapori Capuchin (Cebus Kaapori) considered by the new list of endangered Brazilian species as critically endangered, which means that it can become extinct very quickly. Another monkey, the black-bearded saki (Chiropotes satanas) is also critically endangered. Both species have Gurupi as their main area of occurrence, which means that if the area is further degraded by logging and cleared for cattle pasture, the two species will become extinct.

The fauna of carnivores in the region is diverse, with 14 species, seven of which are on the new list of IBAMA. These animals, even though in theoretically protected areas suffer persecution, especially the big cats: the jaguar and the puma. This is because these animals sometimes prey on livestock in the farms located within the Biological Reserve. The Gurupi also home to the last populations of giant otters in Maranhão. Also present are bush dogs (Speothos venaticus), neotropical otter, grison, raccoon and other species of cats.

Another point of vital importance is the fact that the region is also home to the Awá-Guajás, a semi-nomadic people who live largely as their ancestors lived and who are also threatened with extinction by the greed of loggers, ranchers and others, who invaded their land in search of timber, hunting, supplies for the pharmaceutical industry, and pasture for livestock (including buffalo). This ethnic group that is found only in the region of Gurupi has a population of 250 individuals.