Raccoon Natural History

The common raccoon (Procyon lotor)

The common raccoon is a small, nocturnal carnivore in the family Procyonidae. This family has 2 subgenera, Procyon and Euprocyon. The common raccoon is in the subgenus, Procyon, along with 7 other species of raccoon. There is only 1 species in Euprocyon (Refer to the diagram below). The 6 species of raccoon in Procyon are the: common raccoon (P. lotor), Barbados raccoon (P. gloveralleni), Guadeloupe raccoon (P. minor), Bahamas raccoon (P. maynardi), Trés Marías Islands raccoon (P. insularis) and Cozymel raccoon (P. pygmaeus). The crab-eating raccoon (Euprocyon cancrivorus) is the only living species in Euprocyon.

There are 25 subspecies of the common raccoon, which are discernible by their geographical distribution, physical characteristics, behavior, and in some cases, genetics1. The subspecies of raccoon found throughout Wyoming is the Upper Mississippi Valley raccoon (P. lotor-hirtus)1.

Distribution and Dispersal

Distribution
Raccoons are found in Canada, most of the United States, Mexico and Central America. Over the last few decades, the raccoon has expanded its distribution outside of its historical range. They are now found further west in the United States, specifically in the Rocky Mountain region. They have also expanded their home ranges further north, deeper into Canadian territories1. Raccoons are an introduced species in countries like Japan, Germany, France, Russia, and other countries in the Caucasus region1. Unlike many other animals, raccoons have adapted well to human infrastructure and tend to thrive in urban environments.

Dispersal
Raccoons that live at northern latitudes tend to disperse when they are yearlings, while raccoons at southern latitudes have been known to disperse earlier as juveniles2. Living at a higher latitude requires a greater allocation of resources towards survival during the harsh winters, which is likely why the dispersal age is older for raccoons in these environments. The age of sexual maturity will also influence the dispersal age for a raccoon2.

This map shows both the native and introduced distribution of the common raccoon around the globe. Areas in red are native to the raccoon while areas in blue represent the introduced distribution of the common raccoon.

Physical Characteristics

Fur Coloration & Thickness:
The physical characteristics of the raccoon varies by location. Raccoons that live in densely forested habitats tend to have darker fur than raccoons in coastal and desert regions2. Populations that live in coastal regions are distinguishable by their drastically red coat2. The most striking difference in fur coloration occurs in desert populations, where the raccoons have a blonde to light brown coat color2. Fur thickness is also dependent on the environment. Populations that live at northern latitudes have thicker fur than those at southern latitudes1. Thicker fur enables a raccoon to withstand the harsh winters associated with northern latitudes.

Raccoons have darker colored fur on their dorsal region (back) and lighter colored fur on their ventral region (stomach). Many mammals have this dual coloration including some of the raccoon's closest relatives, like the ringtail and coati. The most notable characteristics of the raccoon are their dark mask and ringed tail. The tail usually has 5-7 bands, alternating in color from black to cream1. The mask and tail pattern for every raccoon is unique to only that individual. These subtle differences are thought to help raccoons identify one another2. When comparing the different sexes and age groups, there are no differences in fur coloration or thickness between females and males and adults and juveniles.

Body Size and Lifespan

The body size of the raccoon varies by location. Raccoons living at northern latitudes have an average body weight anywhere from 20-30 lbs. and an average body length of 16-24 in. long3. The smallest raccoons live on the islands of the Florida Keys3. Raccoons are sexually dimorphic in body size, specifically, females are smaller than males. Fluctuations in body weight will occur from season to season. Raccoons are highly active during the summer and fall when resources are the most abundant4. They typically reduce their travels during the winter and spring due to the harsh weather conditions and limited availability of resources, thus their overall caloric intake is reduced.

Raccoons will typically live for 2-3 years in the wild. This is drastically less than raccoons living in captivity, which have been known to live up to 17-20 years2,5. Raccoon population dynamics are broken down into 3 life stages: nestling, juvenile and adult. Raccoons give birth to altricial young, meaning the young are completely dependent on the mother from birth to around 2 months of age, this is referred to as the nestling stage2. The juvenile stage begins when the raccoon is around 2 months old and can last up to 1 year2. During this time, a juvenile will socialize with its mothers and siblings and will start to travel outside of the den with its family2. The full extent of social learning that takes place between mothers and offspring is not fully understood at this time. This is a topic the University of Wyoming Raccoon Project (UWRP) is interested in investigating. The adult stage starts at around 1 year of age or when a raccoon becomes sexually mature2. Raccoons have many natural predators, including bobcats, pumas, coyotes, eagles, hawks, alligators, dogs and humans2,5. Other factors that regulate raccoon populations include disease and parasites2.

A mother raccoon with her 4 juveniles eating from a can of cat food in a residential backyard.

Skull:
As with all carnivores raccoons have carnassials which are a set of teeth designed for tearing apart flesh. Although raccoons have them, they are poorly developed compared to other carnivores, including other Procyonids like crab-eating raccoons and ringtails. Raccoons have an omnivorous diet which is reflected in the shape of their rounded, cusped molars. Like other omnivores, including bears and humans, raccoons have a bunodont molar dentition. Another distinguishable skull feature of the raccoon is the shape of the auditory bullae. This bony structure is laterally compressed on the outside of the skull and inflated on the inner sides1.

The carnassials are comprised of the fourth premolar on the cranium (P4) and the first molar on the mandible (m1). Notice the characteristic bunodont dentition (blue) of omnivores. The auditory bullae (yellow) of the raccoon are highly inflated on the inner sides.

Senses:

Touch:
A raccoon’s sense of touch is arguably its most powerful sense. The raccoon has 5 unwebbed, digits with short, curved, non-retractable claws on each paw1. Although its forepaws resemble long, thin fingers similar to a human’s or ape's, the raccoon does not have opposable thumbs. The forepaws also contain a type of nerve ending that is different from human and primate nerve endings. 1,2. The forepaws contain a high density of nerve endings that allows a raccoon to discern objects by touch alone. There are about 4 times as many nerve endings in the forepaws then there are in the hindpaws1. It is not uncommon for a raccoon to wet its hands when presented with water. This behavior is thought to provide the raccoon with a heightened sense of touch because the padding on its forepaws become soft and pliable2. Raccoons are especially sensitive to vibrations which allows them to be successful at hunting insects, small mammals, fish and crustaceans1,2.

The forepaw of a raccoon is about 2-2 ½ inches long6. The hindpaw of a raccoon is about 3-3 ½ inches long6.

Sight:
Raccoons are said to be “myopic”, which means they have poor long-distance vision2. Their short-distance vision, on the other hand, is advanced enough to allow them to catch live prey2. Studies have suggested that the raccoon is either color-blind or it has “color-weak” vision1,2. The raccoon's dark mask is thought to be an evolutionary adaptation to its nocturnal lifestyle. The dark fur surrounding the eyes will absorb light from the night sky, which reduces glare while also enhancing night vision2. A light shone at a raccoon late at night will reveal its yellow-green eye shine1.

The raccoon's black mask enhances their night-vision which is critical for this nocturnal animal. Notice the ear tags? Check out Tracking Raccoons to learn more about why this raccoon has an ear tag!

Scent & Taste:
Like many mammals, the raccoon is equipped with a Jacobson’s organ, which is a sensory organ that allows them to distinguish scents and tastes2. This provides the raccoon with an acute sense of smell which is advantageous when foraging for buried food, like insects, rodents, roots and acorns1,2. A raccoon also relies on its sense of smell to distinguish the boundary lines of neighboring raccoons and to identifying individuals1. This animal has a generalist diet, meaning it consumes a wide range of food. They will eat plants, seeds, corn, rodents, fish, crayfish, berries, eggs, etc. They are also known for enjoying sugary foods like: apples, cherries, grapes, dates, melons and even marshmallows2.

Hearing:
For many nocturnal animals a strong sense of hearing is crucial. The raccoon’s ability to hear faint sounds is useful for hunting and avoiding potential predators. Compared to other Procyonids, such as the coati and ringtail, the raccoon does not possess as strong of a sense of hearing1. However, when compared to a dog the raccoon has a heightened sense of hearing2.

Behavior

The strongest social bonds form between a mother and offspring and between siblings. Although the raccoon was once thought to be a solitary mammal, recent research has shown that raccoons will form small groups in some habitats1,2,4,5. The density of raccoons in a habitat will largely influence the sociality of the individuals in a population. When resources are widely dispersed and clumped together, males will become territorial of their home range and defend it against intruders2. Females will occupy areas where there are food resources and shelter, while males will move to areas that will give them access to females. In areas with clumped resources it is not uncommon to see groups of raccoons denning and feeding together2,5. In urban and suburban environments raccoon density is often higher.5 The time of year also influences raccoon sociality. From the late spring into early fall, female raccoons become less social towards non-relatives. During the winter and into spring, raccoons will either den up with their siblings and mother or share communal dens with other raccoons4.

A raccoon and skunk eating within close proximity of one another!

Intelligence:
Research on raccoon intelligence has shown that they are capable of discriminating items based on touch alone2. Another study involving a puzzle box found that raccoons were able to open a latched door that was attached to the box in order to gain access to the food that was inside2. For more information on raccoon cognition check out the work being done by the researchers involved with the University of Wyoming Raccoon Project!

References:
1. Zeveloff, S. I. (2002). Raccoons: A natural history. Washington: Smithsonian Institution Press.
2. MacClintock, D., & Thomas, J. S. (1981). A natural history of raccoons. New York: Scribner.
3. Reid, F. A. (2006). A field guide to mammals of North America. Boston: Houghton Mifflin Company.
4. Prange, S., Gehrt, S.D. and Wiggers, E.P. (2004). Influences of Anthropogenic Resources on Raccoon (Procyon lotor) Movements and Spatial Distribution. Journal of Mammology. 85, 483-490.
5. Gehrt, S.D., Riley, S.P.D., & Cypher, B.L. (2010). Urban Carnivores: Ecology, Conflict, and Conservation. Baltimore: The Johns Hopkins University Press.
6. McDougall, Len. (1997). The Complete Tracker: Tracks, Signs and Habits of North American Wildlife. 1st edition.
Other great resources:
7. Smithsonian National Museum of Natural History