Over the last years there has been new and valuable information in both wild chinchillas, however this is still insufficient for effective protection. In this paper we review some fundamental aspects of its natural history, synthesizing and delivering new information about their ecology, taxonomy and conservation status, based on the review of available literature, and field data collection. In relation to their ecology we have been identified new colonies of both species, for scientific research as well as environmental technical reports. For most of these colonies we identified vegetation to which they are associated, predators and other sympatric rodent species. The taxonomy of these species is controversial. A proposal was submitted to ICZN in 2003, and the recommendations were to describe a neotype for genus and species, but the original specimens described by Bennett (1829), Lichtenstein (1830) and Waterhouse (1844) are in museums from Europe and should be considered as syntypes. Conservation status of both species is critically endangered because most colonies are threatened by mining exploitation. Therefore, it is essential to explore new regions to identify new colonies and compare them with modern methods such as molecular markers. Finally, with this information we argue the need to develop a conservation programs for both species; it should consider critical areas of their biology, such as ecology, genetics and reproduction.