The original habitats of the raccoon are deciduous and mixed forests, but due to their adaptability they have extended their range to mountainous areas, coastal marshes, and urban areas, where some homeowners consider them to be pests. As a result of escapes and deliberate introductions in the mid-20th century, raccoons are now also distributed across mainland Europe, Caucasia, and Japan.
Though previously thought to be solitary, there is now evidence that raccoons engage in gender-specific social behavior. Related females often share a common area, while unrelated males live together in groups of up to four animals to maintain their positions against foreign males during the mating season, and other potential invaders. Home range sizes vary anywhere from 3 hectares (7 acres) for females in cities to 50 km2 (20 sq mi) for males in prairies. After a gestation period of about 65 days, two to five young, known as "kits", are born in spring. The kits are subsequently raised by their mother until dispersal in late fall. Although captive raccoons have been known to live over 20 years, their life expectancy in the wild is only 1.8 to 3.1 years. In many areas, huntingand vehicular injury are the two most common causes of death.
The most important sense for the raccoon is its sense of touch. The "hyper sensitive" front paws are protected by a thin horny layer which becomes pliable when wet. The five digits of the paws have no webbing between them, which is unusual for a carnivoran. Almost two-thirds of the area responsible for sensory perception in the raccoon's cerebral cortex is specialized for the interpretation of tactile impulses, more than in any other studied animal. They are able to identify objects before touching them with vibrissae located above their sharp, nonretractable claws. The raccoon's paws lack an opposable thumb; thus, it does not have the agility of the hands of primates. There is no observed negative effect on tactile perception when a raccoon stands in water below 10 °C (50 °F) for hours.
Raccoons are thought to be color blind or at least poorly able to distinguish color, though their eyes are well-adapted for sensing green light. Although their accommodation of 11 dioptre is comparable to that of humans and they see well in twilight because of the tapetum lucidum behind the retina, visual perception is of subordinate importance to raccoons because of their poor long-distance vision. In addition to being useful for orientation in the dark, their sense of smell is important for intraspecific communication. Glandular secretions (usually from their anal glands), urine and feces are used for marking. With their broad auditory range, they can perceive tones up to 50–85 kHz as well as quiet noises, like those produced by earthworms underground.
Zoologist Clinton Hart Merriam described raccoons as "clever beasts", and that "in certain directions their cunning surpasses that of the fox." The animal's intelligence gave rise to the epithet "sly coon". Only a few studies have been undertaken to determine the mental abilities of raccoons, most of them based on the animal's sense of touch. In a study by the ethologist H. B. Davis in 1908, raccoons were able to open 11 of 13 complex locks in fewer than 10 tries and had no problems repeating the action when the locks were rearranged or turned upside down. Davis concluded they understood the abstract principles of the locking mechanisms and their learning speed was equivalent to that of rhesus macaques. Studies in 1963, 1973, 1975 and 1992 concentrated on raccoon memory showed they can remember the solutions to tasks for up to three years. In a study by B. Pohl in 1992, raccoons were able to instantly differentiate between identical and different symbols three years after the short initial learning phase. Stanislas Dehaene reports in his book The Number Sense raccoons can distinguish boxes containing two or four grapes from those containing three.
Social Behavior Edit
Studies in the 1990s by the ethologists Stanley D. Gehrt and Ulf Hohmann suggest that raccoons engage in gender-specific social behaviors and are not typically solitary, as was previously thought. Related females often live in a so-called "fission-fusion society", that is, they share a common area and occasionally meet at feeding or resting grounds. Unrelated males often form loose male social groups to maintain their position against foreign males during the mating season—or against other potential invaders. Such a group does not usually consist of more than four individuals. Since some males show aggressive behavior towards unrelated kits, mothers will isolate themselves from other raccoons until their kits are big enough to defend themselves. With respect to these three different modes of life prevalent among raccoons, Hohmann called their social structure a "three class society". Samuel I. Zeveloff, professor of zoology at Weber State University and author of the book Raccoons: A Natural History, is more cautious in his interpretation and concludes at least the females are solitary most of the time and, according to Erik K. Fritzell's study in North Dakota in 1978, males in areas with low population densities are solitary as well.
The shape and size of a raccoon's home range varies depending on age, sex, and habitat, with adults claiming areas more than twice as large as juveniles. While the size of home ranges in the inhospitable habitat of North Dakota's prairies lie between 7 and 50 km2 (3 and 20 sq mi) for males and between 2 and 16 km2 (1 and 6 sq mi) for females, the average size in a marsh at Lake Erie was 0.5 km2 (0.19 sq mi). Irrespective of whether the home ranges of adjacent groups overlap, they are most likely not actively defended outside the mating season if food supplies are sufficient. Odor marks on prominent spots are assumed to establish home ranges and identify individuals. Urine and feces left at shared raccoon latrines may provide additional information about feeding grounds, since raccoons were observed to meet there later for collective eating, sleeping and playing. Concerning the general behavior patterns of raccoons, Gehrt points out that "typically you'll find 10 to 15 percent that will do the opposite" of what is expected.
Though usually nocturnal, the raccoon is sometimes active in daylight to take advantage of available food sources. Its diet consists of about 40% invertebrates, 33% plant material and 27% vertebrates. Since its diet consists of such a variety of different foods, Zeveloff argues the raccoon "may well be one of the world's most omnivorous animals". While its diet in spring and early summer consists mostly of insects, worms, and other animals already available early in the year, it prefers fruits and nuts, such as acorns and walnuts, which emerge in late summer and autumn, and represent a rich calorie source for building up fat needed for winter. Contrary to popular belief, raccoons only occasionally eat active or large prey, such as birds and mammals. They prefer prey that is easier to catch, specifically fish, amphibians and bird eggs. When food is plentiful, raccoons can develop strong individual preferences for specific foods. In the northern parts of their range, raccoons go into a winter rest, reducing their activity drastically as long as a permanent snow cover makes searching for food impossible.
One aspect of raccoon behavior is so well known that it gives the animal part of its scientific name, Procyon lotor; "lotor" is neo-Latin for "washer". In the wild, raccoons often dabble for underwater food near the shore-line. They then often pick up the food item with their front paws to examine it and rub the item, sometimes to remove unwanted parts. This gives the appearance of the raccoon "washing" the food. The tactile sensitivity of raccoons' paws is increased if this rubbing action is performed underwater, since the water softens the hard layer covering the paws. However, the behavior observed in captive raccoons in which they carry their food to water to "wash" or douse it before eating has not been observed in the wild. Naturalist Georges-Louis Leclerc, Comte de Buffon, believed that raccoons do not have adequate saliva production to moisten food thereby necessitating dousing, but this hypothesis is now considered to be incorrect. Captive raccoons douse their food more frequently when a watering hole with a layout similar to a stream is not farther away than 3 m (10 ft). The widely accepted theory is that dousing in captive raccoons is a fixed action pattern from the dabbling behavior performed when foraging at shores for aquatic foods. This is supported by the observation that aquatic foods are doused more frequently. Cleaning dirty food does not seem to be a reason for "washing". Experts have cast doubt on the veracity of observations of wild raccoons dousing food.
Raccoons usually mate in a period triggered by increasing daylight between late January and mid-March. However, there are large regional differences which are not completely explicable by solar conditions. For example, while raccoons in southern states typically mate later than average, the mating season in Manitobaalso peaks later than usual in March and extends until June. During the mating season, males restlessly roam their home ranges in search of females in an attempt to court them during the three- to four-day period when conception is possible. These encounters will often occur at central meeting places. Copulation, including foreplay, can last over an hour and is repeated over several nights. The weaker members of a male social group also are assumed to get the opportunity to mate, since the stronger ones cannot mate with all available females In a study in southern Texas during the mating seasons from 1990 to 1992, about one third of all females mated with more than one male. If a female does not become pregnant or if she loses her kits early, she will sometimes become fertile again 80 to 140 days later.
After usually 63 to 65 days of gestation (although anywhere from 54 to 70 days is possible), a litter of typically two to five young is born. The average litter size varies widely with habitat, ranging from 2.5 in Alabama to 4.8 in North Dakota. Larger litters are more common in areas with a high mortality rate, due, for example, to hunting or severe winters. While male yearlings usually reach their sexual maturity only after the main mating season, female yearlings can compensate for high mortality rates and may be responsible for about 50% of all young born in a year. Males have no part in raising young. The kits (also called "cubs") are blind and deaf at birth, but their mask is already visible against their light fur. The birth weight of the about 10 cm (4 in)-long kits is between 60 and 75 g (2.1 and 2.6 oz). Their ear canals open after around 18 to 23 days, a few days before their eyes open for the first time. Once the kits weigh about 1 kg (2 lb), they begin to explore outside the den, consuming solid food for the first time after six to nine weeks. After this point, their mother suckles them with decreasing frequency; they are usually weaned by 16 weeks. In the fall, after their mother has shown them dens and feeding grounds, the juvenile group splits up. While many females will stay close to the home range of their mother, males can sometimes move more than 20 km (12 mi) away. This is considered an instinctive behavior, preventing inbreeding. However, mother and offspring may share a den during the first winter in cold areas.
Life Expectancy Edit
Captive raccoons have been known to live for more than 20 years. However, the species' life expectancy in the wild is only 1.8 to 3.1 years, depending on the local conditions in terms of traffic volume, hunting, and weather severity. It is not unusual for only half of the young born in one year to survive a full year. After this point, the annual mortality rate drops to between 10% and 30%. Young raccoons are vulnerable to losing their mother and to starvation, particularly in long and cold winters. The most frequent natural cause of death in the North American raccoon population is distemper, which can reach epidemic proportions and kill most of a local raccoon population. In areas with heavy vehicular traffic and extensive hunting, these factors can account for up to 90% of all deaths of adult raccoons. Due to a broad range of range overlap with these predators, the most important natural predatorsof the raccoon are bobcats, coyotes, and great horned owls, the latter mainly preying on young raccoons but capable of killing adults in some cases. In Florida, they have been reported to fall victim to larger carnivores like American black bear and cougars and these species may also be a threat on occasion in other areas. Also in the southwest, they are among the favored prey for adult American alligators. On occasion, both bald and golden eagles will prey on raccoons. In rare cases of overlap, they may fall victim from carnivores ranging from species averaging smaller than themselves such as fishers to those as large and formidable as jaguars in Mexico. In their introduced range in the former Soviet Union, their main predators are wolves, lynxes and eagle owls.However, predation is not a significant cause of death, especially because larger predators have been exterminated in many areas inhabited by raccoons.
Although they have thrived in sparsely wooded areas in the last decades, raccoons depend on vertical structures to climb when they feel threatened. Therefore, they avoid open terrain and areas with high concentrations of beech trees, as beech bark is too smooth to climb. Tree hollows in old oaks or other trees and rock crevices are preferred by raccoons as sleeping, winter and litter dens. If such dens are unavailable or accessing them is inconvenient, raccoons use burrows dug by other mammals, dense undergrowth or tree crotches. In a study in the Solling range of hills in Germany, more than 60% of all sleeping places were used only once, but those used at least ten times accounted for about 70% of all uses. Since amphibians, crustaceans, and other animals found around the shore of lakes and rivers are an important part of the raccoon's diet, lowland deciduous or mixed forests abundant with water and marshes sustain the highest population densities. While population densities range from 0.5 to 3.2 animals per square kilometer (1.3 to 8.3 animals per square mile) in prairies and do not usually exceed 6 animals per square kilometer (15.5 animals per square mile) in upland hardwood forests, more than 20 raccoons per square kilometer (51.8 animals per square mile) can live in lowland forests and marshes.