This article by Jerry Cates, first published on 23 April 2010, was last revised on 25 September 2016. © Bugsinthenews Vol. 11:04(11).
Summary: At this time of the year, mother raccoons are busy suckling their young in nests hidden away from prying eyes. The raccoon (Procyon lotor) is a medium-sized mammal native to North America. The photographs shown in this post were taken in the process of excluding a somewhat large colony of raccoons from a commercial structure in Denton, Texas (north of the city of Dallas), in April of 2010. Included in the colony were this mother and her five suckling babes, all of whom were ensconced in a dark, secluded nest, deep inside the eaves of the structure.
It was April, in the midst of raccoon maternity nesting for this region.
In most of Texas, raccoons mate throughout January and February, when estrus, brought on by lengthening daylight hours, begins. After a gestation period of 54-70 days (usually 63-65 days), litters are born in March, April, and May. The kits, as the young are termed, develop in the nest until early fall, when they begin to participate on foraging trips with their mothers.
By late fall, after having learned enough to live on their own, the adolescent raccoons disperse to seek out their own territories, though in urban areas they typically remain within a relatively small ancestral area ranging from just a few to as many as 200 acres. In the wild, raccoons have a typical lifespan of 1.8-3.1 years (Zeveloff 2002), though in captivity they are known to live as long as 20 years.
Studies have found that typical urban areas support raccoon population densities of 130-400 raccoons per square mile. Urbanized females tend to forage within a home range of 7-100 acres, while males forage over ranges of 20-200 acres in size. Within their home ranges, as few as 15% or as many as 43% of urbanized raccoons take shelter during the day in man-made commercial and residential structures that they enter through existing ports of ingress/egress or through holes they create by forcing their way through weak sections of roofing, outside sheathing or eaves. The majority (57% to 85%), however, nest in forested locales within their home ranges.
The common name Raccoon is an adaptation of the proto-Algonquian phrase “ahrah-koon-em.” This phrase roughly translates as “he who rubs, scrubs, and scratches with his hands.” The binomial designation for the genus and species of this animal, Procyon lotor, is derived from Latin and Greek roots:
The generic name Procyon comes from the Greek words προ- “pro” = before, in front of, and -κυων “cyon” = dog, a reference to a primitive kind of dog-like animal. Despite the superficial similarities that prompted this early taxonomic name, molecular DNA analysis suggests that these animals are not like dogs at all, but are more closely related to bears. The specific name lotor derives from the Latin word lotum = a flowing over, a washing, a reference to the tendency of these animals to wash their food before eating it.
Due to numerous mid-20th Century exportations from America to other lands — some intentional, others accidental — the raccoon is now common throughout most of Europe, the Caucasus, and Japan. There, as here, this highly adaptable omnivore is considered a pest of suburban and urban locales, partly because of their unusually high intelligence, adept motor skills and versatile extremities, and the risks attached to human infections from an intestinal parasite that is specific to the raccoon but that cannot reproduce in other animals.
Raccoons are Generally Not Suitable as Pets…
Though having the appearance of cute and cuddly furry creatures that almost demand being petted, these animals are constitutionally incapable of being domesticated unless they are neutered before the age of five or six months. That fact is not obvious in the juvenile or adolescent animal, which during the first six or eight months of life tends to be as habituated to human companionship as any feline or canine pet. However, powerful instincts ultimately override any learned propensities toward ordinary domestication, and these instincts become undeniably clear as soon as the animal achieves sexual maturity. From that point forward, a sexually-intact raccoon’s behavior toward humans is decidedly unfriendly; such raccoons tend to behave in unpredictable ways, even toward long-time human companions, and — particularly during the mating season — are capable of delivering an unexpected, painful, and potentially disfiguring bite.
… and are Often Infected with Diseases and Parasites Dangerous to Humans:
Raccoons are capable of being infected with, and carrying, the rabies virus. According to one authority (Compton 2007), since the mid-1980s, this animal has been responsible for the most intensive rabies outbreak in U.S. history. Though Compton’s study was centered in Pennsylvania, CDC reports substantiate this assertion as applicble to most of the eastern U.S., western U.S., and Texas, as do a number of other reports and studies.
For example, of 4,671 terrestrial rabies cases included in a study conducted in New York (Recuenco 2007), 2,974 (63.7%) were raccoons, 1,063 (22.8%) were skunks, and 634 (13.5%) were other animals including domestic and wildlife species.
As a result, anyone bitten by a raccoon that has not been vaccinated against rabies should presume the animal is rabid, and proceed accordingly.
Beyond rabies and domestication issues lies another problem involving the fact this species tends to carry a number of inportant and dangerous parasites (Ching 2000), including the raccoon-ubiquitous nematode Baylisascaris procyonis.
As many as 70% of adult raccoons, and 90% of juveniles, have been found to be infected with the B. procyonis intestinal parasite, though the prevalance of infection varies regionally. For example, a study of raccoons in Portland, Oregon (Yeitz 2009) indicated a prevalence of 58% in adults and juvenile raccoons, with 70% of juveniles infected, while a study in Tennessee (Souza 2009) showed a prevalence there of 11-15% with little difference between adults and juveniles.
Baylisascaris procyonis in Texas:
Though it was widely believed, for some time, that the Baylisascaris procyonis parasite was not present in raccoons found in Texas (Chandler 1942), that misapprehension — which resulted from a post-mortem study involving no more than 13 raccoon carcasses — was later laid to rest when a significant number of these parasites were discovered in raccoons occurring in coastal areas (Kerr 1997) and in eastern portions of the state. Infection rates of 70% and 23%, respectively, were reported in those two regions at the time. The belief persists, today, that B. procyonis is not common in semi-arid, hot environments and is probably limited by soil types and low raccoon densities, yet a recent study (Long 2006) found significant infections of B. procyonis present in raccoons from a semi-arid region of Texas.
Another recent study (Kresta 2009) of 590 raccoon carcasses from throughout the state found 32 (5.4%) infected with this parasite. The same study identified a total of 20 different species of helminth parasites, 15 of them infecting over 20% of the 590 raccoons examined. Several of these helminth parasites represent serious health risks to humans and their pet dogs and cats, not to mention the other 80 to 90 species of birds and wild animals known to be subject to such infections as a result of living or foraging in close association with raccoons. One is wise, therefore, to presume that any wild raccoon — and for that matter, any wild bird or animal — found anywhere in Texas (plus any domesticated raccoon not specifically examined and treated for helminth parasites), may be carrying parasites that are capable of producing medically threatening helminth diseases in humans and our feline and canine pets.
Baylisascaris procyonis Biology:
Baylisascaris procyonis is a nematode (i.e., a roundworm) whose definitive host is the raccoon. As such, the parasite is particularly able to complete its life cycle in its definitive host, and is less able to do so in other animals. In the case of B. procyonis, the parasite is unable to reproduce in any other animal. In the infected raccoon it becomes a harmless resident of the gut and is essentially harmless to the raccoon host. There the female worm produces 115,000 to 180,000 eggs a day. These eggs are passed out of the raccoon’s body in the feces.
Though Baylisascaris procyonis is not known to reproduce in other animals, it often is hosted by the bodies of rodents and birds, and is capable of infecting the bodies of (and thereby producing a medically threatening disease within) at least 90 other species of wild and domesticated animals, including humans.
In such animals, the eggs hatch in the gut, then — because the developing larvae are unable to reproduce in that environment (conditions of pH and other requirements typical of the raccoon gut are lacking in other animals, including humans) — the larvae go in search of a suitable place to complete their life cycle. Such processes are usually described as larva migrans; when expressed primarily in the skin, it is called cutaneous larva migrans; when involving the internal organs beyond the gut, as in the case of B. ascaris, the condition is described as visceral larva migrans. Here the parasitic larvae penetrate the gut wall and migrate to other parts of the host’s body. There, as before, they fail at reproduction, and so continue to migrate, damaging tissue in myriads of organs before ultimately giving up and encysting. In humans, the larvae are known to migrate to the eyes and the brain, where they cause serious, even fatal, injury.
Fortunately, human infection with this parasite is considered rare. Only 13 cases were reported, for example, between 1980 and 2004. Under-reporting is likely, however, because the primary method of detecting the disease is discovery of the parasite’s lesions during autopsy. Whenever autopsies are not performed, the presence of the disease is not recorded.
The parasite’s eggs can be picked up by breathing the dust of dried fecal matter, or by getting the feces–or dirt contaminated with such feces–on the hands and then transferring the contamination to the mouth. Children, being less careful about cross-contamination than adults, are more at risk.
Cleaning up after these animals, in areas of human habitation, should always be done according to a sterile procedure that includes the use of face masks, rubber gloves, and disinfectants capable of destroying Baylisascaris procyonis eggs. In this vein, one should keep in mind that the eggs of this nematode are unusually resistant to many, if not most, common nematicidal chemicals.
In urban and suburban areas, as well as in the wild, humans should be careful not to contaminate feet, footwear, or other articles that they or others may come into contact with. This is not as easy as it sounds, as the feces of wild animals commonly litters wilderness trails, back yards, and patios of suburban and urban residences. Next time you see wild animal scat in your path, make a conscious effort to step over it, not on it. Scat on a lawn chair or a patio should be treated as an important contaminant to be washed off and avoided. The supposition should always be made that the depositing animal may have a parasitic infection that could be harmful to humans.
For more information on this parasitic disease, see the report published by the CDC in April of 2002.
I was called to a commercial structure in Denton, Texas, in April 2010 to analyze a raccoon invasion that had been going on for some time. Previous efforts by a well-known, nationwide pest control company, to trap and relocate the invading animals, had failed to reduce their numbers. Interior damage included fecal and urine stains on ceiling tiles, broken ceiling tiles, disfigured tile scaffolding (the latter along the perimeter of one office, where the framework had been pushed downward several inches by the animals), and the generation of strong, persistent, and offensive odors.
Inspections of the exterior of the structure revealed that a single ingress/egress locus, with multiple ports, was involved. This was at the electrical service enclosure on one side of the one-story structure. Here could be seen grease stains and characteristic paw prints on metal electrical boxes below, leading to a single ingress/egress port into the structure’s labyrinthian eaves, and above that, to the roof of the building.
Numerous other entry/exit opportunities, to the interior of the structure, exist on the roof, through ventilation ports of various kinds.
However, inasmuch as there is but one way for raccoons to access this roof — specifically via the pipes and boxes affixed to the wall of the electrical enclosure — all those potential ports could be eliminated merely by sealing the upper reaches of the enclosure itself. In fact, attempts had been made to do just that, sometime in the distant past, but those previous efforts had been circumvented by these crafty animals long ago. More recent efforts, by a nationwide pest control company, to deal with this raccoon invasion had been limited to trap-and-relocate techniques, without attempting to seal the roof access. I suspect the daunting task involved in sealing such a large port (6 feet in width by 12 feet in length) had led them to try to exhaust all other alternatives first.
It is likely that the property manager at this site would have balked, initially, at the expense involved in sealing this port, even if the pest control company first called to the scene had recommended it. It is not known if such a recommendation was made, but that seems doubtful for two reasons: First, responsible, experienced wildlife specialists know that is the only reasonable way to begin to deal with this problem, so if they were knowledgeable enough to recommend it they should have been responsible enough to insist on doing it that way. But, let’s suppose they did recommend it, but were rebuffed because of the higher initial cost; once it became evident that trap-relocate-release was not working, they would have been able to use that as leverage to get the manager to allow them to do things the right way. Instead, however, they simply told the manager to be patient, as trap-relocate-release would eventually work.
A series of trap-and-release sessions by that company, spanning a period of several months, had been undertaken with no observable impact on the raccoon invasion at this site. The aggregate costs of those unproductive sessions probably exceeded the price I ultimately quoted to properly seal the access port, including the installation of two custom-made one-way-doors (OWDs); one in the large port itself, another in the eave. By the time I was called in, which was rather late in the process, the property manager was thoroughly frustrated, at wit’s end, and psychologically prepared for any reasonable expense, provided a conclusion to the raccoon invasion could be guaranteed. I always provide such guarantees as part of my contract fee, but many others do not; it was learned later that another wildlife specialist had provided a slightly lower quote at the same time as mine, but could not guarantee — with absolute certainty, as I did — that his approach would solve the raccoon invasion once and for all.
Why one-way-doors are often necessary…
The one port into the eave, for its part, could easily have been sealed using a variety of alternative materials. However, sealing this port precipitously would only increase the risk of damage to the interior of the structure. One is as likely to seal raccoons into the building as to seal them out. And, as all husbandmen of wild animals know, it is extremely foolhardy to seal a raccoon into a building:
The sealed-in animal will either create a brand-new exit port, at considerable damage to that part of the structure, or will remain within and content itself with wreaking havoc with the contents of the structure. Neither alternative leads to happy conclusions, for the building’s human inhabitants or for the raccoon(s).
It is appropriate, in such discussions as this one, to posit a few words about the practice of trapping and relocating raccoons and similar animals. Anyone can buy a wild animal trap at the local feed store. The cost is low, and the instructions for using such devices are easy to follow. Yet, using such traps — hoping to bring wild animal incursions into commercial and residential structures to a stop — almost always have unhappy outcomes. That fact partly explains why the practice is frowned upon by most authorities, as well as by practically all experienced, responsible wildlife specialists. Once a few simple facts are understood, the reasons why trap-and-relocating does not work are fairly obvious, but absent such an understanding those reasons seem somewhat esoteric, if not counter-intuitive. Perhaps that explains why many so-called pest control companies still employ trap-and-relocation as a primary means of dealing with wild animals.
Wrapping one’s mind around this question is worth the effort. Trap-and-relocation, at least when speaking of endemic populations of raccoons, opossums, skunks, armadillos, bats, snakes, and squirrels, almost never works to the advantage of property owners and property managers.
- Wild animals are all around us, and generally comprise a much larger population than we realize; some, such as squirrels, are diurnal and are often seen during the day, but most — such as rats, mice, opossums, raccoons, skunks, armadillos, bats, and snakes — are nocturnal, only forage after dark, and are rarely observed.
- It is impractical, if not impossible, to eliminate the natural (endemic) populations of wild animals from the surrounding environment; steps taken to deal with them must recognize their presence as an accepted fact, though steps can and should be taken to reduce their food sources so their populations do not spiral out of control.
- Any temporary reduction in the numbers of a particular wild animal, via trap-and-relocation methods, will — in general — quickly be defeated by newly arriving animals, either from surrounding areas or through natural population increases.
- Thus the object of a rational wild animal control program must be to enable endemic populations of such animals to continue to coexist — not necessarily with us, but certainly near us, at reasonable population levels — while simultaneously preventing all such wild animals from causing damage to our property, and avoiding all the health risks that such wild animals potentially pose to us, our children, and our feline and canine pets.
The presence of unrestricted wild animal food sources, and of ingress and egress ports in our residential and commercial structures that grant access to endemic wild animal populations, encourage the exploitation of such places for nesting, reproduction, and food gathering. Eliminating such food sources, and closing all ingress and egress ports, so wild animals cannot use them for nesting, reproduction, or food gathering, is the key to wild animal control.
By judiciously preventing wild animals from foraging for food nearby, and gaining access to, our residential and commercial structures, we should be able to live in an environment free of the presence of wild animals that might pose risks to us, our children, and our pets. On the other hand, any traps installed in a vain attempt to capture and relocate such animals must be monitored and baited, and the trapped animals must then be dealt with humanely as soon as they are caught.
It is important to recognize the importance of applying humane methods when dealing with wild animals. Today, strict avoidance of inhumane (i.e., cruel) treatments of wild animals is not only a moral imperative, but also a legal one that — if violated — can result in serious criminal charges. In Texas, the charge of animal cruelty has recently been elevated to the level of a felony under certain circumstances.
Animal cruelty involving depriving an animal of food or water, abandoning an animal, transporting an animal in a cruel manner, injuring someone else’s animal, and overworking an animal, can result in being charged with a Class A misdemeanor, which on conviction may include a fine up to $4,000, jail time up to a year, or both. If the conviction is a third offense involving these actions, the state may punish the defendant with a state jail felony. Under Texas law, a state jail felony may include jail time ranging from 180 days to 2 years and a fine up to $10,000.
Certain forms of animal cruelty warrant harsher punishments even on the first conviction. For cruelty offenses involving the torture, killing, seriously injuring, poisoning, fighting, or tripping of an animal, a state jail felony may be imposed on the first conviction. Persons convicted three times under these harsher penalties may be subjected to a third degree felony sentence, resulting in imprisonment ranging from 2 to 10 years and a possible fine of up to $10,000.
In summary, besides being generally unproductive, the protocols and mechanics involved with a trap-and-relocation program easily become quite burdensome, costly, and risky, insofar as they pose a raft of legal liabilities when handled inhumanely or cruelly.
By comparison, advanced exclusionary techniques focusing on erecting specialized physical barriers that prevent the animals from entering a structure, and — in the case of animals that are already occupying the interior of a structure — that enable them to leave but not to reenter, are uniformly successful. Furthermore, they almost never require that any of the animals be trapped and relocated, and adroitly avoid the risks of inhumane or cruel mistreatments.
Notice, while we’re on the subject of raccoon behavior, the well-developed sharp, non-retractable claws, shown in the photograph at left. These claws, photographed on the paw of one of the juvenile raccoons removed from the eave of the structure, are used by the adult raccoon to pull itself up and over objects, making the animal a good climber despite its relatively short legs. Because it necessarily brushes against inanimate objects while on repetitive sojourns, one can expect to see evidence of its passage in the oily markings its body leaves behind.
Equally important to the claws are the vibrissae, or whiskers, that project beyond them. On seeing these whiskers on the digits of this raccoon, one might naturally assume that they are merely manifestations of its essential hairiness, but they are much more important than they appear. The raccoon is able, by virtue of these sensory hairs, to so thoroughly analyze an object in total darkness — without even touching it –— as to be able to identify its shape and, thus, the kind of animal, or inanimate object, that it is.
Over 66% of that part of the cerebral cortex of the raccoon brain responsible for sensory perception is devoted to the interpretation of tactile impulses. This, combined with unusually versatile and flexible hands and feet, make the raccoon a formidable opponent when one seeks to keep it out of any structure it may yearn to enter.
H. B. Davis, in a study he conducted a century ago, discovered that raccoons were virtual Houdini’s among the wild animals. Davis devised a series of complicated locks for the raccoons to try to master as a means of gaining access to an enclosure containing food. The hungry animals managed to unlock 11 of them after less than 10 attempts. When he rearranged the locks, or reoriented their positioning, the raccoons were not deterred, a fact that Davis interpreted as proof that they utilized abstract reasoning to a degree comparable to that demonstrated by certain Old World monkeys (specifically rhesus macaques).
Instead of sealing the eave access port, it was necessary to install a sturdy one-way door (OWD). The OWD had to be constructed so that the raccoon could easily depart the structure through it, but could not use it as a means to reenter the building. To work, the OWD had to be of a design that could not be unlocked by an animal the size of the raccoon. In other words, when approached from inside the building it must open quickly, with only minimal effort on the part of the raccoon, but when approached from the outside, it must be positively unyielding. Of course, that means it must also be sturdy enough to thwart efforts to dismantle it by these persistent, strong, and intelligent animals.
The OWD is the linchpin of the raccoon-exclusion process, and every OWD is unique in one way or another.
But first the top of the electrical enclosure had to be sealed so that raccoons could no longer gain access to the roof. That was done, in this particular instance, by using 2×4 lumber framing, with two cross-members, and — initially — with chicken wire stapled to the framing and trimmed out with 2 x 0.25 wood trim designed to prevent the raccoons from peeling it away from its stapled moorings. Of course, chicken wire is not the perfect barrier for raccoon exclusion, because a determined raccoon will succeed in penetrating it. The operative expression is “determined”, as chicken wire does a good job of excluding raccoons from areas they are not yet habituated to. And, if several entry/exit ports exist, as may be the case here (it was not possible to determine, from a cursory inspection, if the port into the eaves articulated with the roof or not), then the chicken wire would lead the raccoons to use an open port, rather than expend the energy and suffer the injuries coincident with forcing their way through it.
When, however, the raccoons forced their way through the chicken wire, as they did at this site, that provided two essential bits of information: first, it confirmed that the port in the eave did not articulate with the roof, and second, by the location of the hole made in the wire, it identified the exact location where the raccoons were passing through to the roof. That served to identify where the for the roof access would have to be installed.
Since the mother raccoon’s kits had just been taken away (she was too quick to catch), she needed time to grieve, for her milk glands to return to normal, and for her hormones to stabilize before the OWD was installed. If the door was put in place too hastily, she might have refused to go through it, which would be tantamount to sealing her into the building. Fortunately, she would not be ready to reproduce again for at least 60-90 days, though she would be back to normal — in terms of essential attitude and behavior patterns — in the span of three days or so. Based on that logic, a specially constructed OWD was installed three days later.
Update: On Monday, 26 April 2010, three days after the raccoon kits were removed from the eave, the chicken wire enclosure was completed. The wire was framed out in yellow pine trim (that was treated with disodium octaborate tetrahydrate wood preservative after the job was complete) over treated 2×4 lumber, so that the raccoons would have to pass through it, or through the eave port, to reach the roof. A one-way door was installed over the eave port. The next morning it was observed that the OWD over the eave port had not been used, but that raccoons had penetrated the chicken wire barrier at one location (the far end of the enclosure, about one third the distance of the short side).
Considerable work was subsequently expended to deal with the remnants of the raccoon colony that kept trying to reenter this structure. Because of the architecture of the opening to the roof, it was necessary to reinforce all of the chicken wire with 1/4th inch hardware cloth, layered in such a manner that the raccoons on the roof could easily slip between the horizontal layers of hardware cloth to reach the middle of the opening, and from there drop to the ground below. Reentry was foiled by the fact that the reentering raccoons would have to scale a 24-inch section of hardware cloth, from underneath, before reaching the nearest open layer, then apply enough upward force on the upper layer of wire to make an opening to squeeze through, a feat that even the most determined raccoon was unable to accomplish. Over the period of several days, all but one of the raccoons on the roof of this building were eventually excluded by the OWD just described. The one raccoon that remained behind had to be trapped.
The large male raccoon shown at left was trapped on top of the roof on 6 May 2010. This lone hold-out was either too large, or too cantankerous, to follow the example of the others, all of whom had succeeded in traversing the OWD.
His continued presence was no secret to the human occupants of the structure, who continued to hear noises of the animal rummaging around in the attic. It was imperative that he be trapped quickly, or starvation would soon end its life, and starving wild animals is to be avoided at all costs.
On 5 May 2010, three humane traps were placed on the roof and baited with food materials that raccoons are attracted to. These traps are designed not to harm trapped animals, but they still have parts capable of cutting the animal’s flesh if it tries too hard to extricate itself.
Raccoons and opossums, in particular, are rather bad about doing everything they can to get out of a trap, even if they hurt themselves in the process. For example, an older male opossum that had gotten so worked up, while trapped in one of these humane traps deployed by a maintenance worker at a nursing home, was observed to have torn its flesh and broken several teeth in a frenetic effort to get away. Unfortunately, not much can be done to prevent all such injuries, but one wonders if changes could be made to the traps to keep such injuries to a minimum.
At 6:00AM the next morning, on returning to the roof, the first trap was observed to have been emptied of bait without being sprung. The bait in the second trap had not been touched, but the third trap contained the highly irritated, extremely pungent animal shown in Fig. 9. It had abraded the skin of its front extremities on the steel plates of the cage, and a small amount of blood was noticeable under the trap. An extremely objectionable odor, emanating from the animal’s fur, was very strong.
In the wild, at least in a normal wilderness area where this omnivore can find abundant vegetarian dishes to supplement its carnivorous appetite for fresh meat, no unusual smells are noticeable. That is true even when several of them congregate together, as I can attest from experiences I’ve had with hundreds of them milling around my feet in the forests of east Texas.
In an urban setting, however, where they eat mostly putrefying table scraps — usually heavily weighted with spoiled meat products — from dumpsters and trash cans, these animals take on a highly offensive odor.
This fellow smelled so bad the odor lingered in the author’s nostrils for hours after he was finally released, some eighty miles away in a heavily forested wilderness area. In this new location, far away from civilization, he has at least some chance of returning to the life his ancestors lived. Sadly, though, he will likely depart that idyllic setting to raid the garbage of nearby homes and businesses, especially if the humans there are not careful about garbage sanitation. Once tempted by that lifestyle, it is almost impossible for these animals to return to the natural settings of their ancestral past.
Taxonomy: Note that on-going advances in DNA sequence analyses, retrotransposon presence or absence data, and the debates such advances engender within the scientific community, are presently muddying the waters of the taxonomical world. At the heart of this chaotic atmosphere is the transition taking place between traditional Linnaean taxonomical designations, based on anatomical characters, and cladistic nomenclature based on genomic characters. Until this transition is settled by the adoption of a uniform and widely accepted nomenclature any effort to list the taxonomy of a given organism will necessarily include designations that are in dispute. The list that follows reflects that necessity.
- Kingdom Animalia (ahn-uh-MAYHL-yuh) — first described in 1758 by the Swedish taxonomist Carolus Linnaeus (23 May 1707 – 10 January 1778), using the Latin word animal = “a living being,” from the Latin word anima = “vital breath”, to refer to multicellular, eukaryotic organisms whose body plans become fixed during development, some of which undergo additional processes of metamorphosis later in their lives; most of which are motile, and thus exhibit spontaneous and independent movements; and all of whom are heterotrophs that feed by ingesting other organisms or their products;
- Phylum Chordata (kohr-DAY-tuh) — animals that have, at some point in their life cycle, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail.
- Clade Craniata (kray-nee-AH-tuh) — a clade of chordate animals that contains, as living representatives, the Myxini (hagfish), Petromyzontida (including lampreys), and Gnathostomata (jawed vertebrates); craniates are animals with a hard skull, of bone or cartilage, in the phylum Chordata.
- Subphylum Vertebrata (vurr-tuh-BRAY-tuh) — chordate animals with backbones and spinal columns;
- Infraphylum Gnathostomata (nah-thow-stoh-MAW-tuh) — the jawed vertebrates; derived from the Greek nouns γνάθος (gnathos) = “jaw” + στόμα (stoma) = “mouth”; comprised of some 60,000 species, i.e., 99% of all living vertebrates; living gnathostomes also have teeth, paired appendages, and a horizontal semicircular canal of the inner ear, with other physiological and cellular anatomical characters such as myelin-sheathed neurons, and an adaptive immune system that utilizes V(D)J recombination, rather than genetic recombination in the variable lymphocyte receptor gene, to create antigen recognition sites; it is presently believed that Gnathostomata evolved from ancestors that already possessed a pair of both pectoral and pelvic fins;
- Clade Eugnathostomata (yew-NAH-thow-stoh-mah-tuh) — the Chondrichthyes (cartilaginous fishes), and the
Osteichthyes (bony fishes);
- Clade Osteichthyes (oss-tee-ICK-thee-eez) [Huxley, 1880] — the bony fish; a diverse taxonomic group of fish with skeletons primarily composed of bone tissue, as opposed to cartilage; most fish are members of Osteichthyes, a diverse group of 45 orders, 435 families and 28,000 species comprising the largest class of vertebrates presently recognized; divided into ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii); oldest known fossils of bony fish are about 420 million years old and are transitional fossils that display a tooth pattern between that of the tooth rows of sharks and bony fishes; in comparison to Euteleostomi, in paleontological terms, the terms are synonymous; in ichthyology, the Euteleostomi presents a cladistic view which includes the terrestrial tetrapods that evolved from lobe-finned fish, whereas on a traditional view, Osteichthyes includes only fishes and is therefore paraphyletic; however, recently-published phylogenetic trees treat the Osteichthyes as a clade;
- Superclass Tetrapoda (teh-trah-POH-duh) — derived from the ancient Greek expression τετραπόδηs = “four-footed” and comprised of the first four-limbed vertebrates and their descendants, including living and extinct amphibians, birds, mammals, reptiles and some ancient, exclusively aquatic creatures such as the Acanthostega; evolved from the lobe-finned fishes around 390 million years ago in the middle Devonian Period; modern tetrapod groups appeared by the late Devonian, 367.5 million years ago; specific aquatic ancestors of the tetrapods, and the processes leading to land colonization, remain unclear; most present species are terrestrial but the first tetrapods were fully aquatic; most present amphibians are semiaquatic and live the first stage of life as fish-like tadpoles; amniotes evolved about 340 million years ago (crown amniotes 318 mya), and their descendants are believed to have driven most amphibians to extinction; one population of amniotes diverged into lizards, dinosaurs, birds and their relatives, while another diverged into mammals and their extinct relatives; several groups of tetrapods, such as the caecilians, snakes, cetaceans, sirenians, and moas have lost some or all of their limbs; many tetrapods have returned to partially aquatic or fully aquatic lives; the first returns to an aquatic lifestyle may have occurred during the Carboniferous Period; the change from a body plan for breathing and navigating in water to a body plan enabling the animal to move on land is one of the most profound evolutionary changes known;
- Clade Reptiliomorpha (repp-till-ee-oh-MOR-fuh) [Säve-Söderbergh, 1934] — proposed by Professor Gunnar Säve-Söderbergh in 1934 to designate amniotes and various types of late Paleozoic tetrapods more closely related to amniotes than to living amphibians, based on the belief that amphibians had evolved from fish twice, one group composed of the ancestors of modern salamanders, the other — which Säve-Söderbergh referred to as Eutetrapoda — comprising the anurans (frogs), amniotes and their ancestors, with the origin of caecilians being uncertain. Säve-Söderbergh’s Eutetrapoda consisted of two sister-groups: Batrachomorpha, containing anurans and their ancestors, and Reptiliomorpha, containing anthracosaurs and amniotes; he subsequently added Seymouriamorpha to his Reptiliomorpha as well; Alfred Sherwood Romer rejected Säve-Söderbergh’s theory of a biphyletic amphibia and used Anthracosauria to describe the labyrinthodont lineage from which amniotes evolved; un 1970, the German paleontologist Alec Panchen took up Säve-Söderbergh’s name for this group as having priority, but Romer’s terminology is still in use; some writers preferring phylogenetic nomenclature use Anthracosauria;
- Clade Amniota (amm-nee-OH-tuh) [Haeckel, 1866] — from Greek ἀμνίον (AMM-nee-awn) = “membrane surrounding the fetus”, and with an earlier meaning of “(the) bowl in which the blood of sacrificed animals was caught”, from ἀμνός (AMM-nos) = “lamb”; a clade of tetrapod vertebrates comprised of reptiles, birds, and mammals that lay eggs on land or retain fertilized eggs within the mother’s body; distinguished from anamniotes (fishes and amphibians) that typically lay eggs in water; include synapsids (mammals along with their extinct kin) and sauropsids (reptiles and birds), as well as their ancestors; amniote embryos are protected by extensive membranes; in eutherian mammals such as humans, these membranes include the amniotic sac that surrounds the fetus; embryonic membranes and the absence of a larval stage distinguish amniotes from tetrapod amphibians; first or “basal” amniotes resembled small lizards and evolved from the amphibian reptiliomorphs about 312 million years ago in the Carboniferous period; their eggs could survive out of the water, allowing amniotes to expand into drier environments; the eggs could also “breathe” and cope with wastes, allowing the eggs and the amniotes themselves to evolve into larger forms;
- Clade Synapsida (suh-NAPP-suh-duh) [Osborn, 1903] — the synapsids (from the Greek expression meaning ‘fused arch’), are synonymous with the theropsids (from the Greek expression meaning ‘beast-face’), and include both mammals and every other animal that is more closely related to mammals than to other living amniotes; distinguished from other amniotes by the presence of a temporal fenestra, or opening, low in the skull roof behind each eye having a bony arch beneath each eye that first appeared in the Late Carboniferous period, 312 million years ago, and accounts for the designation; primitive synapsids are often referred to as pelycosaurs or pelycosaur-grade synapsids, while more advanced mammal-like synapsids are referred to as therapsids; the non-mammalian members are described as mammal-like reptiles in classical systematics, and are often called stem mammals or proto-mammals; synapsids evolved from basal amniotes and comprise one of the two major groups of the later amniotes, the other being the sauropsids, which comprises the modern reptiles and birds; synapsids were the largest terrestrial vertebrates in the Permian period, 299 to 251 million years ago, though some of the larger pareiasaurs, appearing at the end of Permian period, matched their size;
- Clade Eupelycosauria (yew-puh-lee-koh-SAW-ree-uh) [Kemp, 1982] — originally used to refer to a suborder of ‘pelycosaurs’ (Reisz 1987), but presently used (see Laurin and Reisz 1997) to designate a clade of synapsids that includes most pelycosaurs, as well as all therapsids and mammals; first appeared during the Early Pennsylvanian epoch (e.g., Archaeothyris, and an earlier genus, Protoclepsydrops), and represent a stage in the acquisition of mammal-like characteristics (Kemp 1982), in contrast to their earlier amniote ancestors; defining characteristics separating these animals from the Caseasauria (also pelycosaurs) are based on proportional dimensioning of certain bones of the skull, including a long, narrow supratemporal bone that contrasts with caseasaurs where the width of the supratemporal bone is almost as great as its length, and a frontal bone that widely connects to the upper margin of the orbit (Laurin and Reisz 1997);
- Clade Sphenacodontia (sfenn-uh-coh-DON-tee-uh) — a stem-based clade of derived synapsids defined by Amson and Laurin (2011) as “the largest clade that includes Haptodus baylei, Haptodus garnettensis and Sphenacodon ferox, but not Edaphosaurus pogonias”; they first appear during the Late Pennsylvanian epoch; basal Sphenacodontia constitute a transitional evolutionary series from early pelycosaurs to ancestral therapsids, ancestors of more advanced forms and mammals, thus sometimes referred to as proto-therapsids;
- Clade Sphenacodontoidea (sfenn-uh-coh-don-TOY-dee-uh) — a node-based clade defined to include the most recent common ancestor of the Sphenacodontidae and the Therapsida, along with their mammalian and non-mammalian descendants; distinguished in accord with a number of specialized characteristics concerning proportional dimensioning of bones of the skull and of the teeth; evolved from earlier Sphenacodontia such as Haptodus via a number of transitional stages of small, unspecialized pelycosaurs;
- Clade Therapsida (thuh-RAPP-suh-duh) [Broom, 1905] — a group of synapsids, including mammals and their ancestors; many traits today seen as unique to mammals had their origin within early therapsids, including having their four limbs extend vertically beneath the body, as opposed to the sprawling posture of other reptiles; earliest fossil attributed to Therapsida is Tetraceratops insignis from the Lower Permian; evolved from pelycosaurs (specifically sphenacodonts) 275 million years ago; replaced the pelycosaurs as the dominant large land animals in the Middle Permian; replaced by the archosauromorphs in the Triassic; the therapsids include the cynodonts, the group that gave rise to mammals in the Late Triassic around 225 million years ago; of non-mammalian therapsids, only cynodonts and dicynodonts survived the Triassic–Jurassic extinction event; the last of the non-mammalian therapsids, the tritylodontid cynodonts, became extinct in the Early Cretaceous, approximately 100 million years ago;
- Clade Eutherapsida (yew-thuh-RAPP-suh-duh)
- Clade Neotherapsida (nee-oh-thuh-RAPP-suh-duh) [Hopson, 1999] — a clade of therapsids, that includes anomodonts and the more derived theriodonts, which include mammals;
- Clade Theriodontia (thee-ree-oh-DON-tee-uh)[Owen, 1876] — derived from ancient sources meaning “Beast Tooth”, a reference to the more mammal-like teeth displayed by the animals comprising this major group of therapsids; when defined in traditional, Linnaean terms, they form a suborder of mammal-like reptiles that lived from the Middle Permian to the Middle Cretaceous; when defined in cladistic terms, they include traditional theriodonts and their mammalian descendants; appeared at about the same time as the anomodonts, some 265 million years ago in the Middle Permian;
- Clade Eutheriodontia (yew-thee-ree-oh-DON-tee-uh) [Hopson & Barghusen, 1986] — a clade of therapsids, erected by Hopson & Barghusen in 1986, that includes therocephalians and cynodonts; the close relationship between therocephalians and cynodonts has been recognized for many years, as they are thought to have diverged in the Middle Permian, and each group independently evolved mammal-like features, including a secondary palate and the loss of the postorbital bar, both of which were retained in mammals, which are considered a derived group of cynodonts; mammalian features that both groups inherited from a common ancestor include loss of teeth on the palate, expansion of the epipterygoid bone at the base of the skull, and narrowing of the skull roof to a narrow sagittal crest running between large temporal openings;
- Clade Cynodontia (sinn-oh-DON-tee-uh) [Owen, 1861] — therapsids with “dog teeth” that first appeared in the Late Permian, some 260 million years ago; includes modern mammals, including humans, as well as their extinct ancestors and close relatives; non-mammalian cynodonts spread throughout southern Gondwana and are represented by fossils from South America, Africa, India, and Antarctica; in northern continents, fossils have been found in eastern North America as well as in Belgium and northwestern France; one of the most diverse groups of therapsids;
- Clade Mammaliamorpha (muh-may-lee-uh-MOHR-fuh) — the clade originating with the last common ancestor of Tritylodontidae and the crown group mammals, and as such a wider group than mammaliaformes, such that it includes some families that trait-based taxonomy does not include in Mammalia, in particular Tritylodontidae and Brasilodontidae;
- Clade Mammaliaformes (muh-may-lee-uh-FOR-mees) [Rowe, 1988] — a clade containing the crown group mammals and their closest extinct relatives; the group, which radiated from earlier probainognathian cynodonts, is defined as the clade originating from the most recent common ancestor of Morganucodonta and the crown group mammals; the latter is the clade originating with the most recent common ancestor of extant Monotremata, Marsupialia, and Placentalia; besides Morganucodonta and the crown group mammals, it includes Docodonta and Hadrocodium as well as the Triassic Tikitherium, the earliest known member of the group; Mammaliaformes is a term of phylogenetic nomenclature; by contrast, the assignment of organisms to Mammalia has traditionally been founded on traits and, on this basis, Mammalia is slightly more inclusive than Mammaliaformes; trait-based taxonomy generally includes Adelobasileus and Sinoconodon in Mammalia, though they fall outside the Mammaliaformes definition;
- Class Mammalia (muh-MAIL-yuh) [Linn. 1758] — from the Latin noun mamma = “breast”, a clade of endothermic amniotes distinguished from reptiles and birds by the possession of a neocortex region in the brain, hair, three middle ear bones and mammary glands; includes the largest animals on the planet, the great whales, as well as some of the most intelligent, such as elephants, primates and cetaceans; basic body type is a terrestrial quadruped, but some mammals are adapted for life at sea, in the air, in trees, underground or on two legs; the largest group of mammals have a placenta, which enables the feeding of the fetus during gestation; mammals range in size from the 30–40 mm (1.2–1.6 in) bumblebee bat to the 30-meter (98 ft) blue whale; except for the five species of monotreme (egg-laying mammals), all modern mammals give birth to live young; most mammals, including the six most species-rich orders, belong to the placental group; the three largest orders in number of species are Rodentia: mice, rats, porcupines, beavers, capybaras and other gnawing mammals; Chiroptera: bats; and Soricomorpha: shrews, moles and solenodons; the next three biggest orders, depending on the biological classification scheme used, are the Primates including the great apes and monkeys; the Cetartiodactyla including whales and even-toed ungulates; and the Carnivora which includes cats, dogs, weasels, bears and seals;
- Magnorder Boreoeutheria (boh-ree-oh-yew-THEE-ree-uh) — from the Greek noun βόρειο = “north” + the Greek adjective ευ = “good” + the Greek noun θεριό = “beast”; a magnorder, which the International Code of Zoological Nomenclature (ICZN) uses to designate a clade of unusually important significance, of placental mammals comprised of the sister taxa Laurasiatheria (most hoofed mammals, most pawed carnivores, and several other groups) and Euarchontoglires (Supraprimates); this magnorder is now well supported by DNA sequence analyses, as well as retrotransposon presence or absence data; the earliest known fossils belonging to this magnorder date to about 65 million years ago, shortly after the K-Pg extinction event, though molecular data suggests they may have originated earlier, during the Cretaceous period; with the exception of rhinoceroses and cetaceans, male members of the clade share the distinction of external testicles
- Superorder Laurasiatheria (larr-ay-shuh-THEE-ree-uh) — a superorder of placental mammals that originated on the northern supercontinent of Laurasia some 99 million years ago, and that includes shrews, pangolins, bats, whales, carnivorans, odd-toed and even-toed ungulates, among others; Laurasiatheria was founded on the basis of the similar gene sequences, and retrotransposon presence or absence data, that are shared by the mammals that belong to it; as no anatomical features have yet been found that unite the group, Laurasiatheria is a clade, without a Linnaean rank, but with the cladistic rank of superorder; the name reflects the theory that these mammals evolved on the supercontinent of Laurasia, after it split from Gondwana when Pangaea broke up; it is a sister group to Euarchontoglires (or Supraprimates) with which it forms the clade Boreoeutheria;
- Clade Scrotifera (skrow-TIFF-er-uh) — a proposed clade of mammals within Laurasiatheria, consisting of six orders and their common ancestors, arranged within the two subgroups Chiroptera (the bats) and Ferungulata; the name derives from the word scrotum, a pouch in which the testes permanently reside in the adult male; thus all members of the group have a postpenile scrotum, often prominently displayed, except for some aquatic forms and pangolin (for which the testes lie just below the skin); it appears to be an ancestral character for this group, yet other orders generally lack this as an ancestral feature, with the probable exception of Primates;
- Clade Ferungulata (feer-un-gew-LAH-tuh) — a traditional clade within the cohort of placental mammals; established by George Gaylord Simpson in 1945, it includes the extant Carnivora, Perissodactyla and Artiodactyla as well as Tubulidentata and a superorder, Paenungulata, plus a number of orders known only as fossils; though Simpson placed whales (Cetacea) in a separate cohort, recent evidence linking them to Artiodactyla would mean that they belong here as well; Simpson established the grouping on the basis of morphological criteria, but this traditional understanding of Ferungulata has been challenged by a more recent classification, relying upon genetic criteria, in which his ferungulate orders are divided between two distinct cohorts, Afrotheria and Laurasiatheria; advocates of this newer system redefine Ferungulata as a clade within Laurasiatheria, comprising the larger portion of the former Ferungulata and including ‘true’ ungulates (Perissodactyla and Artiodactyla), whales and Carnivora, with the addition of pangolins (Pholidota), but excluding Tubulidentata and paenungulates; a newer clade name, Scrotifera, described above, has thus been proposed;
- Clade Pegasoferae (pegg-uh-soh-FEER-ee) — a proposed clade of mammals based on genomic research in molecular systematics by Nishihara, Hasegawa and Okada; to the surprise of the authors, their data led them to propose a clade that includes bats (order Chiroptera), carnivores such as cats and dogs (order Carnivora), horses and other odd-toed ungulates (order Perissodactyla) and pangolins (order Pholidota) as springing from a single evolutionary origin within the mammals; the name Pegasoferae was coined from the name of the mythological flying horse Pegasus to refer to bats and horses, and the term Ferae, encompassing carnivorans and pangolins; according to this, the odd-toed ungulates’ closest living relatives are the carnivorans; earlier theories of mammalian evolution have aligned bats with the insectivores (order Eulipotyphla) and horses with the even-toed ungulates (order Artiodactyla); some subsequent molecular studies published shortly afterwards have failed to support the authors’ conclusions, in particular, two recent studies, each combining genome-wide analyses of multiple taxa with testing of competing alternative phylogenetic hypotheses, conclude that Pegasoferae is not a natural grouping;
- Clade Zooamata (zoh-ah-MAH-tuh) — a clade of mammals consisting of Ferae (carnivores and pangolins) and Perissodactyla (odd-toed ungulates); together with Cetartiodactyla (even-toed ungulates and whales) and chiroptera (bats) it forms Scrotifera (formerly Ferungulata), and is part of Laurasiatheria; the name is constructed from Greek and Latin to mean “animal friends”, a reference to the inclusion of cats, dogs, and horses; a conflicting proposal links the Perissodactyla and Cetartiodactyla in a clade named Euungulata; both proposals are based on molecular evidence, but neither of these clades is fully supported;
- Clade Ferae (FEER-ee) — a clade of mammals, consisting of the orders Carnivora (over 260 species worldwid) and Pholidota (eight species of pangolins in tropical Africa and Asia); pangolins do not look much like carnivorans (wolves, cats, seals, and so on), and were thought to be the closest relatives of Xenarthra (armadillos, sloths, and so on), but recent DNA research found a close relationship to carnivorans; Ferae were also thought to include Creodonta, extinct primitive carnivoran-like mammals, but it turned out to be a polyphyletic assemblage of unrelated mammal groups; several extinct orders, relatives of Pholidota, are members of the Ferae, as well; an alternate name, Ostentoria, has also been proposed for a grouping of the Carnivora and Pholidota; according to recent studies the closest relatives of Ferae are Perissodactyla (horses, tapirs, and rhinos) and Cetartiodactyla (which combines Artiodactyla—camels, pigs, ruminants and hippos—with Cetacea—whales and dolphins); an alternate phylogeny (less supported) holds that the closest relatives to the Ferae are the Perissodactyla and Chiroptera (bats), not Cetartiodactyla; Ferae together with Perissodactyla has been called Zooamata. Ferae, Perissodactyla, and Chiroptera together has been called Pegasoferae;
- Clade Carnivoramorpha (kar-nih-vor-ah-MOR-fuh) — a clade of mammals that includes the modern order Carnivora, but that also includes a paraphyletic superfamily that had been traditionally divided into two families of carnivores: Miacidae (the miacids) and Viverravidae; Miacoids were primitive carnivores that lived during the Paleocene and Eocene Epochs, about 33-66 million years ago; today Miacidae is recognized as a paraphyletic array of stem taxa that probably resulted in some “miacid” genera ending up just outside the order Carnivora, the crown-group within the Carnivoramorpha. Carnivoramorpha consists of both Miacoidea and Carnivora, but excludes the order Creodonta that existed alongside Carnivoramorpha; Miacoids are regarded as basal carnivoramorphs; the miacids are a paraphyletic group containing all miacoids that are not viverravids; the transition from miacids to Carnivora was a gradual trend during the Paleocene to late Eocene, with taxa from both North America and Eurasia involved; the miacids did not appear until the very end of the Paleocene and are characterized by their shorter skull, and loss of contact between the calcaneum and fibula in the ankle; Miacoids were mostly small carnivores superficially reminiscent of martens or civets. They probably fed on invertebrates, lizards, birds and smaller mammals like shrews and opossums, while others may have been insectivores. Some species were arboreal, others lived on the ground. Their teeth and skull show that the miacoids were less developed than modern carnivores.
- Order Carnivora (kar-NIH-vor-uh) [Bowdich, 1821] — from Latin carō = “flesh”, + vorāre “to devour”); a diverse order comprised of more than 280 species of placental mammals whose members are referred to as carnivorans, whereas the word “carnivore”, which is often popularly applied to members of this group, can more broadly refer to any meat-eating organism; carnivorans are more diverse in size than any other mammalian order; members range from the least weasel (Mustela nivalis), weighing in at 25 g (0.88 oz) and sized at 11 cm (4.3 in) in length, to the polar bear (Ursus maritimus), which can weigh up to 1,000 kg (2,200 lb), to the southern elephant seal (Mirounga leonina), whose adult males weigh up to 5,000 kg (11,000 lb) and measure up to 6.9 m (23 ft) in length; some carnivorans, such as cats and pinnipeds, depend entirely on meat for their nutrition; others, such as raccoons and bears, depending on the local habitat, are more omnivorous: the giant panda is almost exclusively a herbivore, but will take fish, eggs and insects, while the polar bear subsists mainly on seals; carnivorans have teeth and claws adapted for catching and eating other animals; many carnivorans hunt in packs and are social animals, giving them an advantage over larger prey;
- Family Procyonidae (pro-see-AWN-nuh-dee) — a New World family of the order Carnivora that includes the raccoons, coatis, kinkajous, olingos, olinguitos, ringtails and cacomistles; procyonids inhabit a wide range of environments and are generally omnivorous, and are relatively small animals, with generally slender bodies and long tails (though the common raccoon tends to be bulky); many procyonids have banded tails, and distinctive facial markings; like bears, procyonids are plantigrade, walking on the soles of their feet; most species have non-retractile claws; because of their general build, the Procyonidae are often popularly viewed as smaller cousins of the bear family; this is reflected in their German names: a raccoon is called a Waschbär (washing bear, as he “washes” his food before eating), a coati is a Nasenbär (nose-bear) while a kinkajou is a Honigbär (honey-bear); the Dutch follow suit, calling the animals wasbeer, neusbeer and rolstaartbeer respectively; however, it is now believed that procyonids are more closely related to mustelids than to bears; due to their omnivorous diet, procyonids have lost some of the adaptations for flesh-eating found in their carnivorous relatives; while they do have carnassial teeth, these are poorly developed in most species, especially the raccoons;
- Genus Procyon (PRO-see-awn) — a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae; the most familiar species, the common raccoon (P. lotor), is often known simply as “the” raccoon, as the two other raccoon species in the genus are native only to the tropics and less well known; genetic studies have shown that the closest relatives of raccoons are the ring-tailed cats and cacomistles of genus Bassariscus, from which they diverged about 10 million years ago;
- Species Procyon lotor (pro-see-awn LOH-torr) — the raccoon, sometimes spelled racoon, is also known as the common raccoon, North American raccoon, northern raccoon, and colloquially as coon, is a medium-sized mammal native to North America. The raccoon is the largest of the procyonid family, having a body length of 40 to 70 cm (16 to 28 in) and a body weight of 3.5 to 9 kg (8 to 20 lb). Its grayish coat mostly consists of dense underfur which insulates it against cold weather, two of the raccoon’s most distinctive features are its extremely dexterous front paws and its facial mask, which are themes in the mythology of several Native American ethnic groups; raccoons are noted for their intelligence, with studies showing that they are able to remember the solution to tasks for up to three years; the diet of the omnivorous raccoon, which is usually nocturnal, consists of about 40% invertebrates, 33% plant foods, and 27% vertebrates; 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 ranges vary from 3 hectares (7.4 acres) for females in cities to 5,000 hectares (12,000 acres) 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 1.8 to 3.1 years; in many areas, hunting and vehicular injury are the two most common causes of death.
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