The Raccoon’s Success
Raccoons have a vast transcontinental distribution, occurring throughout most of North
America and Central America. [A] They are found from southern Canada all the way to
Panama, as well as on islands near coastal areas. [B] They occur in each of the 49 states
of the continental United States. [C] Although raccoons are native only to the Western
Hemisphere, they have been successfully transplanted to other parts of the globe. [D]
Following a decline to a relatively low population level in the 1930s, raccoons began to
prosper following their 1943 breeding season. A rapid population surge continued
throughout the 1940s, and high numbers have been sustained ever since. By the late
1980s, the number of raccoons in North America was estimated to be at least 15 to 20
times the number that existed during the 1930s. By now, their numbers have
undoubtedly grown even more, as they have continued to expand into new habitats
where they were once either rare or absent, such as sandy prairies, deserts, coastal
marshes, and mountains. Their spread throughout the Rocky Mountain West is indicative
of the fast pace at which they can exploit new environments. Despite significant numbers
being harvested and having suffered occasional declines, typically because of disease, the
raccoon has consistently maintained high population levels.
Several factors explain the raccoon’s dramatic increase in abundance and distribution.
First, their success has been partially attributed to the growth of cities, as they often
thrive in suburban and even urban settings. Furthermore, they have been deliberately
introduced throughout the continent. Within the United States, they are commonly taken
from one area to another, both legally and illegally, to restock hunting areas and,
presumably, because people simply want them to be part of their local fauna. Their
appearance and subsequent flourishing in Utah’s Great Salt Lake valley within the last 40
years appears to be from such an introduction. As an example of the ease with which
transplanted individuals can succeed, raccoons from Indiana (midwestern United States)
have reportedly been able to flourish on islands off the coast of Alaska.
The raccoon’s expansion in various areas may also be due to the spread of agriculture.
Raccoons have been able to exploit crops, especially corn but also cereal grains, which
have become dependable food sources for them. The expansion of agriculture, however,
does not necessarily lead to rapid increases in their abundance. Farming in Kansas and
eastern Colorado (central and western United States) proceeded rapidly in the 1870s and
1880s, but this was about 50 years before raccoons started to spread out from their
major habitat, the wooded river bottomlands. They have also expanded into many areas
lacking any agriculture other than grazing and into places without forests or permanent
streams.
Prior to Europeans settling and farming the Great Plains region, raccoons probably were
just found along its rivers and streams and in the wooded areas of its southeastern
section. With the possible exception of the southern part of the province of Manitoba,
their absence was notable throughout Canada. They first became more widely distributed
in the southern part of Manitoba, and by the 1940s were abundant throughout its
southeastern portion. In the 1950s their population swelled in Canada. The control of
coyotes in the prairie region in the 1950s may have been a factor in raccoon expansion.
If their numbers are sufficient, coyotes might be able to suppress raccoon populations
(though little direct evidence supports this notion). By the 1960s the raccoon had
become a major predator of the canvasback ducks nesting in southwestern Manitoba.
The extermination of the wolf from most of the contiguous United States may have been
a critical factor in the raccoon’s expansion and numerical increase. In the eighteenth
century, when the wolf’s range included almost all of North America, raccoons apparently
were abundant only in the deciduous forests of the East, Gulf Coast, and Great Lakes
regions, though they also extended into the wooded bottomlands of the Midwest’s
major rivers. In such areas, their arboreal habits and the presence of hollow den trees
should have offered some protection from wolves and other large predators. Even
though raccoons may not have been a significant part of their diet, wolves surely would
have tried to prey on those exposed in relatively treeless areas.
