Figure 1: North American Raccoon (The Learning Company, Inc. 1997).
San Francisco State University
Geography 316: Biogeography
The Biogeography of the Raccoon (Procyon
lotor)
by Kirsten Leising, student in Geography 316, Fall 2000
Figure 1: North American Raccoon (The Learning Company, Inc. 1997).
Kingdom: Animalia
Phylum:
Chordata
Class:
Mammalia
Order: Carnivora
Family: Procyonidae
Genera: Procyon
Species: Procyon lotor
Early historical writings of North America note the
raccoon as a curious, unique, and intelligent creature. The name “raccoon”
came from an Algonquian Indian word for this medium-sized carnivore: they called this
remarkable animal arakun (also spelled arakunem, aroughcun, arocoun,
and arathkone); translated it means “he scratches with his hands.”
The Sioux Indians called the masked animal wica (or weé-cha, or way-atch-a)
which means “little man.” Virginian colonists dropped the beginning from arakun,
and the name became raccoon. (MacClintock 1981)
Description of Species:
The most distinguishing features of raccoons are
their black eye masks, bushy ringed tails, and pointed black ears with white trim (Fox
2000). The raccoon’s coat has a rather grizzled appearance with dark colored
hair ranging from a dark gray and black color above with buff or rust colors
interspersed. To help with concealment the raccoon has a light buff colored
underside, and when viewed on a tree branch from below their light color blends in with
the light sky; when viewed from above their dark color blends into the dark forest
floor. The variations in raccoon coat coloration mostly depend on geographic
location, where the darkest coat colors are in the most humid climates, the lighter
colored coats in the dryer, desert climates, and in the southeast coastal regions the
coats have a lighter, reddish color. The raccoon’s bushy tail with black brown
tip has between 5 and 7 dark rings including the tip. The tail is used for fat
storage during the fall, for balance while climbing, and as a brace when sitting on its
haunches (MacClintock 1981; Goldman 1950).
The raccoon’s coat has two layers: a
coarser, longer haired guardcoat to shed moisture, and a insulating, thicker, shorter
haired undercoat. The undercoat comprises 90% of the raccoon’s
hair. The “guard hairs are termed multiple-banded agouti because each is
marked by four alternate light and dark bands ... ” the two bands closest to the tip
of the hair affect the raccoon’s overall color. (MacClintock 1981 p. 2) The
coat’s thickness is directly related to latitude (and temperature), with the northern
raccoons having thicker coats than their relatives down south. Annually, beginning
in the spring, the raccoon sheds its coat, giving the raccoon a very shabby look during
summer, but by August the thick coat is well on its way to growing back for the winter
(MacClintock 1981).
The raccoon has special forepaws shaped very much like
tiny human hands with five fingers and amazing dexterity. Raccoons constantly use
their hands to touch and feel their food (The Gable 2000). Their hindpaws also have
five digits and look like small human feet, both fore- and hindpaws have long claws on
them to help them while digging and climbing (MacClintock 1981).
The raccoon’s body shape is similar to that of a
small bear. Body length is anywhere from 24” to 40” including the tail
which is 8” to 12” long. Female raccoons reach adult size after one year
and males will reach adult size after two years (Fox 2000). The ranges for raccoon
weights are between 4.6 - 8.6 kg for females and are between 5.8 - 11.0 kg for males
(Gehrt & Fritzell 1999). Weight variations are due to seasonal fluctuations, in
which raccoons lose weight in March at about the time they reproduce and the temperatures
start to warm. Weight also varies with latitude; studies show northern raccoons tend
to weigh more than the southern ones (Gehrt & Fritzell 1999; Fox 2000).
Habitat:
Raccoons will live in any woodlands near
water. They are found all across North America and only cold temperatures keep them
away. Raccoons live in wetlands, plains, and especially forests. They prefer
hollow trees for their dens, but will live in rock crevices and caves, on the ground in
swamps under cedars, brush, abandoned buildings, and other animals’ abandoned ground
burrows. The further north the more insulated the dens will be. Raccoons sleep
during the winter months, but they do not hibernate and have been known to venture out
occasionally in the cold weather months (Tesky 2000).
Natural History:
Life span: In the wild, raccoons rarely reach their potential life span of ten to twelve years, but a tagged female was known to live in the wild 12 ½ years before being shot. Because conditions in the wild are so harsh, raccoons are lucky to survive five years and have the mean life span determinations of 1.8 years for Missouri raccoons and 3.1 for Alabama raccoons. In captivity, on the other hand, raccoons can live a stress-free and long life - the record was a male that lived seventeen years and twenty-seven days (MacClintock 1981).
Eating habits: A nocturnal animal, raccoons sleep during the day and forage for food at night. They are omnivorous, and in the wild, eat crayfish, birds, mammals, fish, eggs, insects, earthworms, frogs, berries, nuts, fruits, corn, vegetable matter, and even carrion, but in the city, garbage cans are a favorite target (Vessel & Harrington 1961; MacClintock 1981). Raccoons have two ways of eating, dry feeding and dabbling; both are done while the raccoon gazes away into space and uses its acute sense of touch to investigate its meal. Dry feeding is done with certain types of foods like nuts, and the raccoon rolls or rubs the object of food, to examine and then consume it. On the other hand, dabbling is done where water is nearby and while catching fish, crayfish, etc.: the raccoon lays its hands just under the water and excitedly touches the substrate and rocks and their crevasses for food (MacClintock 1981). It has been noted by many that raccoons in captivity seem to wash their food, unlike their wild counterparts. Studies have found this behavior is not an act of cleaning the food, but it is a natural outlet for normal activities in the wild (MacClintock 1981). Raccoons must masticate their food because they have a narrow gullet and therefore they do not gulp their food like many other carnivores do (MacClintock 1981). Cypher and Cypher (1999) found a mutualistic relationship between persimmon seeds and raccoons. It turns out that persimmons have much higher germination rates after ingestion of the seeds by raccoons. There has been a coevolution factor proposed between raccoons and persimmons, as they have historically been located in the same range together (Cypher & Cypher 1999).
Reproduction: Raccoons are both polygamous and
promiscuous (Tesky 2000). Raccoons mate between January and March with a peak in
February. Mating is stimulated by warmer temperatures and lengthening
photoperiod. In their winter dens, the females begin their long estrous period, and
the males wake up to search for mates. The male raccoon begins to travel from den to
den, searching for a willing female in estrus. Once the pair have copulated, the
male will leave to mate again with another. The southern raccoons mate a little
later in the season and for a slightly longer period. The females can mate as
yearlings, but males usually wait until their second year to mate. Gestation is
approximately 63 to 65 days. The females have 6 mammae and litter size is between 1
and 8 cubs, normally 3 - 5 cubs, with only one litter a year. The young are born
with their eyes and ears closed; with the eyes opening in 2 - 3 weeks and the ears just
after that. The cubs are very vocal with many mews, purrs, wails, screeches, and
growls. The cubs will walk in 4 to 6 weeks, and by the 7th week the cubs will be
running and climbing (MacClintock 1981). During the first month the mother rarely
ventures out of the den, but once the young are 5 weeks or so the mother may begin to
venture out for 8 - 12 hours at a time to hunt for food and groom herself. The young
stay with their mother for the first year or so, or until they reach adult size
(MacClintock 1981; The Gable 2000).
Evolution:
A placental mammal, Procyon lotor, the
common North American raccoon, is a member of the family Procyonidae under the order of
Carnivora. All carnivores originally evolved as predators. During the
Cretaceous period, about 135 million years ago (mya), the earliest known placental mammals
were insectivores. These mammals were small and tree dwelling, and the niches they
filled are today occupied by moles, hedgehogs, and shrews (Savage & Long 1986).
Beginning 65 mya, during the Paleocene period, there was an increase in the number of
these small mammals, due to adaptation to a wide variety of habitats (MacClintock 1981).
Figure 2: Evolutionary Tree of Carnivores (Savage & Long 1986).
These precursors to modern mammals split into five
distinct groups. One of these groups, the creodonts, includes the primitive
ancestors of all carnivores, and they possessed bear-like, hyena-like, and cat-like
forms. During the Eocene period, 55 - 37 mya, the miacids entered the fossil record,
and it is believed that these slender-bodied, five-toed, tree-climbing mammals are the
ancestors of present-day carnivores. Because the miacids were more flexible and had
a dentition advantage over the creodonts, they exploited new habitats and foods. It
was during a period of adaptive radiation that the carnivores began to adopt various forms
for different environments and foods. The adaptive radiation led to different
dentition needs, and some carnivores became mixed feeders, such as raccoons.
Raccoons have both the carnivore carnassial shear, to feed on flesh, and the expanded
molars for crushing. The order of Carnivora split into two groups, the Canoidea and
the Feloidea. The four living canoid families, the Canidae (dogs), the Ursidae
(bears), the Procyonidae (raccoons), and the Mustelidae (weasels), are all closely related
according to hemoglobin samples (MacClintock 1981).
It is not clear if the Procyonids were directly evolved
from the miacids or are a representation of an early offshoot of the canid line.
“Fossil evidence and distribution of chromosome numbers indicates that the bears,
too, arose from the dogs.” (MacClintock 1981 p.115) The center of procyonid
diversification was the area now known as Central America. The raccoon’s
ancestry has been successfully traced back to the genera Phlaocyon and Cynodictis from the
Lower Miocene or Oligocene (37 mya) periods (Goldman 1950). By the early Pleistocene
period, 2.5 mya, the genus Procyon was well represented throughout North America, where it
ranged from the Atlantic to the Pacific oceans across the present United States (Goldman
1950).
Distribution:
The geographic distribution of the North American
Raccoon, Procyon lotor, reaches from southern Canada, down throughout the United
States (except for parts of the Rockies, Utah, and Nevada), and all the way into
Panama. It also includes many islands from Tres María in southern Mexico to the
Bahamas and the Lesser Antilles, West Indies (See Figure 1, Goldman 1950.) The
raccoon’s altitudinal range begins at sea level and continues up waterways, i.e.,
streams, to such elevations as ~5000 feet in some parts of the Rocky Mountain range and to
~9000 feet in the mountains near Ajusco, south of the Valley of Mexico (Goldman
1950). The raccoon prefers temperate and tropical climates and generally stays away
from the cold temperatures of the higher latitudes and the top elevations of
mountains. As noted by Goldman (1950 p. 31), Procyon lotor
“occupies the Tropical, Austral, Transition, and lower parts of Canadians
Zones.”
Otherwise, raccoons are eager to adapt to any
environment and are only geographically limited by long winters (because of water staying
frozen too long), therefore, they are found living in coastal areas, upland marshes,
prairies, forests, and last but not least, suburbs and cities (MacClintock
1981). A highly adaptable species, the raccoon lives almost anywhere
there is an ample source of food and availability of den sites, which are hollow trees,
caves, and even brush piles.
Map of Distribution:
Figure 3: Distribution of species and subspecies of the subgenus Procyon
(Goldman 1950).
Other interesting issues:
Verbalization:
Raccoons are thought to have over two hundred different
sounds used for communication. These raccoon sounds can be heard at the Raccoon
Sounds website: http://members.aol.com/dhswan3/index.html.
The Raccoon’s Predators:
The raccoon’s enemies are mostly nocturnal like
they are, and it is the young raccoons that are the most likely to become prey. Some
of the raccoon’s predators are: great horned owl, red tailed hawk (during the
day), bobcats, lynx, puma, coyote, red fox, fishers, wolves, red wolves, golden eagles,
and large snakes. Humans are the raccoon’s worst enemy, mostly due to hunting,
trapping, and our cars (MacClintock 1981).
Rabies:
Rabies is common in raccoon populations, but they do
not seem to the spread the disease to other species easily. Passive and unaggressive
while infected by rabies, rabid raccoons are probably less likely to appear than they
would be if otherwise healthy (Tesky 2000).
Bibliography/Website address:
Compton’s Interactive Encyclopedia 1998 ed. The Learning Company, Inc. 1997. (Raccoon photo.)
Cypher, Brian L., and Ellen A. Cypher. 1999. “Germination Rates of Tree Seeds Ingested by Coyotes and Raccoons.” The American Midland Naturalist 142 (1): 71-6.
Fox, Rebecca; Biology 108 student. (May 2000). Procyon lotor. [online]. Available: http://animaldiversity.ummz.umich.edu/accounts/procyon/p._lotor$media.html [25 October, 2000].
Gehrt, Stanley D., and Erik K. Fritzell. 1999 “Growth Rates and Intraspecific Variation in Body Weights of Raccoons (Procyon lotor) in Southern Texas.” The American Midland Naturalist 141(1): 19-27.
Gable, The. (October 21, 2000). [online]. Available: http://www.geocities.com/RainForest/Vines/4892/main.html [25 October, 2000].
Goldman, Edward A. 1950. Raccoons of North and Middle America. Washington: U.S. Government Printing Office.
MacClintock, D. 1981. A Natural History of Raccoons. New York: Charles Scribner’s Sons.
Savage, R. J. G., and M. R. Long. 1986. Mammal Evolution: An Illustrated Guide. London: British Museum (Natural History).
Swanson, Damon. (10/14/97). Raccoon Sounds. [online]. Available: http://members.aol.com/dhswan3/index.html [26 November, 2000].
Tesky, Julie L. (July 28, 1998). Procyon lotor. [online]. Available: http://www.huntana.com/feis/animals/mammal/prlo/ [25 October, 2000].
Vessel, M. F., and E. J. Harrington. 1961. Common Native Animals. San Francisco: Chandler Publishing Company.
Zim, Herbert S., and
Donald F. Hoffmeister. 1955. Mammals. New York: Golden Press.
send comments to bholzman@sfsu.edu
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