At the start of her 2008 field season at El Parque El Piñalito in the Misiones province in northeastern Argentina, Ilaria Agostini knew something was terribly wrong. Agostini has studied Misiones’ two howler monkey species since 2005—brown (Alouatta guariba clamitans) and black and gold (A. caraya) howlers. Both lived at relatively low densities in the park, but still existed in one of the most continuous, well-preserved remnants of habitat known as the Atlantic Forest. She knows them better than anyone in the world.
Click here for original story, Mutations may have saved brown howler monkeys from yellow fever virus
Source: Phys.org