Taxonomy and Systematics
The Procyonidae (raccoon family) includes around a dozen species in six genera. Because the members of this family are diverse in appearance, they were not immediately recognized by early naturalists as a coherent group, causing some confusion. For example, the Northern Raccoon (Procyon lotor) was described first as a fox and then a bear and the Kinkajou (Potos flavus) was originally described as a primate (a lemur), based in part on its forward-facing eyes (Kays 2009).
Kays (2009) recognized the following six genera and 12 species:
Bassaricyon (3 species [but now 4]): Lowland Olingo (B. alleni), Northern Olingo (B. gabbii), and a then undescribed species, from the Andean cloud forests of Colombia and Ecuador, that has since been described (Helgen et al. 2013) as the Olinguito (B. neblina). Helgen et al. (2013) also recognized a fourth species, B. medius. They concluded that B. gabbii occurs in Central America and that the Lowland Olingo actually includes two species, B. alleni on the eastern side of the Andes and B. medius on the western side.
Bassariscus (2 species): Ringtail (B. astutus), found on the west coast of the United States through the southwest and into northern Mexico, and Cacomistle (B. sumichrasti), found in Central America and southern Mexico.
Nasua (2 species): South American Coati (Nasua nasua), found over much of South America except for the southern third, and White-nosed Coati (Nasua narica), found throughout Central America and into the southwestern United States. The Dwarf (or Cozumel) Coati, from Cozumel Island, Mexico, is sometimes recognized as a distinct species, N. nelsoni.
Nasuella (1 species [but now 2]): Mountain Coati (Nasuella olivacea), found in montane forests above 2000 meters in northwestern South America. Helgen et al. (2009) suggested that this might be the least studied carnivore genus globally. Morphological and molecular phylogenetic investigations by Helgen et al. led them to the conclusion that there are actually two distinct mountain coati species, which they referred to as the Eastern Mountain Coati (Nasuella meridensis), found in the Venezuelan Andes and formerly recognized as a subspecies, and the Western Mountain Coati (N. olivacea), found in the Andes of Colombia and Ecuador. Their molecular phylogenetic analyses also suggested that Nasuella may fall within the genus Nasua as the sister lineage to Nasua narica, making the genus Nasua paraphyletic as currently defined, although a strong conclusion on this question will require additional morphological and genetic comparisons, including data from independent genetic markers. If this conclusion stands, however, the genus name Nasuella would likely be relegated to a synonym of Nasua and all the coatis and mountain coatis would be included in the genus Nasua..
Potos (1 species): Kinkajou (Potos flavus), found from southern Mexico through the northern half of South America east of the Andes.
Procyon (3 species): Crab-eating Raccoon (P. cancrivorus), found from southern Central America through the northern two thirds of South America east of the Andes; Northern Raccoon (Procyon lotor), found from southern Canada through Central America (and established as an invasive species in Europe, Russia, and Japan); and Cozumel Raccoon (P. pygmaeus), from Cozumel Island, Mexico. Dozens of supposedly distinct forms of Northern Raccoon have been described over the years, but based on more recent work these are not considered to be valid. Interestingly, one result is that raccoons on many Caribbean islands that were formerly viewed as several distinct endemic species worthy of special conservation efforts are now viewed as invasive pests from the mainland that threaten local biodiversity. Similarly, the extinction of the Barbados Raccoon (last recorded in 1964) is now viewed as a stroke of good luck for the biodiversity of Barbados rather than a sad loss. The raccoons on Cozumel Island are believed to have arrived there long before humans and are still generally recognized as a distinct species, athough this could change once variation in mainland forms is studied more thoroughly.
Procyonids are medium-sized carnivores, ranging from around 1 to 10 kg. Only the coatis show significant sexual dimorphism, with males being larger. All procyonids can climb well, but some are far better adapted than others for arboreal life: raccoons and coatis frequently climb trees for food or safety but rarely move among tree canopies, whereas the Kinkajou is one of the most arboreally specialized species in the order Carnivora, regularly moving from treetop to treetop in the dark, covering 2 km in a night. Kinkajous have fully reversible hindfeet, allowing them to descend branches and hang, and have remarkable vertebral flexibility. The Kinkajou and the Binturong (family Viverridae) are the only carnivorans with a prehensile tail, from which they often hang to reach fruit. Kinkajous are also unusual in having a fully convergent grasp, i.e., they are able to hold objects (such as food) with one hand.
Most procyonids are habitat generalists, although the Olinguito and mountain coatis are Andean cloud forest specialists. Procyonids are generally associated with trees and any forest across most of the Americas is likely to be home to at least one procyonid (as many as six species in some parts of Panama). Kinkajous are found in virtually all tropical forest types from lowland rainforest to high cloud forest to dry forest. White-Nosed and South American Coatis also use a wide variety of forest types, but move into drier chaco, cerrado, and mountainous deserts as well. Raccoons are tied to the aquatic environments they feed in. They find abundant habitat in wet forests, but also follow waterways and shorelines into drier habitats. In addition, Northern Raccoons thrive in suburban and even urban habitats (especially since the 1970s and 1980s). Ringtails are found in a range of forest habitat types, but are less tied to forest than other procyonids, often occurring in rocky deserts with cliffs. Cacomistles are found only in rainy tropical areas, but use a range of habitats, including mature oak cloud forest, secondary forest, and overgrown pastures. Some procyonids actually seem to benefit from human activity (e.g., Northern Raccoons and, to a lesser extent, Ringtails) and Cacomistles, South American Coatis, White-nosed Coatis, and Kinkajous seem to tolerate moderate forest fragmentation reasonably well, so long as they are not heavily hunted. Some other procyonids, such as mountain coatis and Olinguitos are believed to be far more sensitive to habitat disturbance, although little information is available for these taxa.
Procyonids are among the least carnivorous of all families in the Carnivora. Northern Raccoons are extreme omnivores and Kinkajous are surely among the most frugivorous mammals. Data from Panama, Venezuela, and French Guiana indicated that the Kinkajou diet is up to 99% fruit, although a study in Bolivia found substantial amounts of ants and ant nest material in the stomachs of six Kinkajous.
The most arboreal procyonids (Kinkajous, olingos, Cacomistles) make loud calls that probably function to communicate over long distances. This is unusual in the Carnivora, although common for arboreal primates.
Most procyonids are generally nocturnal, spending the day sleeping in a tree cavity or or rock den and only emerge after sunset. Coatis, however, sleep in trees during the night and are active during the day. Coatis are also the most social procyonids. Females and their young travel in groups of up to 65 individuals, although smaller groups of 10 to 30 are more common. Adult male coatis (especially South American Coatis) sometimes trail along, but are more likely to forage alone. Kinkajous and Northern Raccoons have also been found to exhibit some degree of sociality, at least under some circumstances.
Because most procyonids are nocturnal, and often arboreal, they tend not to intreract much with humans. Although in the tropics they may take some fruit from gardens, they tend to be viewed more as charming visitors than pests (Northern Raccoons raiding suburban and urban garbage cans are more often viewed as pests). Starting in the 1980s, a new strain of raccoon rabies spread rapidly through high density populations in the eastern United States, reducing urban raccoon populations but also threatening other wildlife and even humans. At times, there has been a significant trade in raccoon pelts, ranging from 400,000 to two million over most of the 20th century, but peaking at a harvest of 5.1 million individuals in the winter of 1979/80.
Although most procyonid species are not threatened at this point in time, the Cozumel Raccoon and Cozumel (or Dwarf ) Coati are highly endangered (Kays  treated the former as a valid raccoon species and the latter as a subspecies of the White-nosed Coati, but he noted that the Cozumel Coati is sometimes treated as a full species). The Olinguito has a small range in a region with intense conversion of forest to agriculture; the mountain coatis also have small ranges and may be threatened by conversion of their forest habitat to agriculture.
(Kays 2009 and references therein)