Variation in demographic patterns and population structure of raccoons across an urban landscape

Raccoons (Procyon lotor) are considered synanthropic, with high densities reported from urban landscapes. However, little information is available on population density and demography within the urban matrix. To better understand how urban land-use patterns influence raccoon density and demographic patterns, we sampled raccoons at multiple, replicated sites across an urban landscape. Density differed by land-use type (F_2,17 = 4.66, P = 0.027): urbanized sites, = 4.96 ± 2.64 raccoons/km², range = 1.25–10.00 raccoons/km²; urban open sites, = 14.84 ± 6.35 raccoons/km², range = 3.00–29.25 raccoons/km²; rural open sites, = 15.50 ± 4.66 raccoons/km², range = 13.00–20.25. Although we found no clear patterns in sex ratio, reproductive condition, or body condition, we observed differences in age structure among urban open, rural open, and urbanized sites. The most striking difference was the absence of older animals at urbanized sites and relatively low numbers of young individuals at urban open sites. Raccoons were the dominant mesocarnivore in open fragments, but less so in the urban matrix. Spatial variation in density across urban landscapes is likely influenced by site level differences in abundance of anthropogenic resources and differences in habitat quality. Furthermore, the association between changes in land-use and population age structure may have reflected different mortality sources across the landscape. Our results illustrate that wildlife species considered synanthropic may have complex relationships with urban landscapes. © 2012 The Wildlife Society.     

Ultracytochemistry of glycoproteins in the eccrine nasolabial glands of the North American raccoon (Procyon lotor)

The distribution and quality of glycoproteins was studied by means of electron microscopic cytochemical methods, particularly lectin cytochemistry, in the secretory cells of the eccrine nasolabial glands of the North American raccoon (Procyon lotor). In the dark and clear glandular cells, complex glycoconjugates were demonstrable, predominantly, in secretory granules, the cisternae of the Golgi apparatus, the surface coat of the plasma membrane, and as glycogen particles. Secretory granules found in the dark cells contained a variety of saccharide residues, such as α-d-mannose, β-d-galactose, β-N-acetyl-d-glucosamine and sialic acid. Several sugars were also detectable in the surface coat of the plasma membrane and the Golgi apparatus.The results obtained may be helpful to understand the specific functions of the glandular secretions of the raccoon nasolabial glands. These could be, particularly, binding of water on the snout surface and protection against microbial hazards, to maintain the structural and functional integrity of the relatively thin snout epidermis in carnivores.     

Is the Guadeloupean racoon (Procyon minor) really an endemic species? New insights from molecular and chromosomal analyses

The Guadeloupean racoon has been chosen as the emblematic species of the Parc National de Guadeloupe because of its supposed endemic specificity. However, its taxonomic position is not clearly defined. At what period did this animal colonize Guadeloupe and how it reached the island remain unsolved questions. To clarify these points, insular and continental individuals (Procyon lotor), coming from five localities and belonging to three subspecies, were compared using molecular (sequencing of a 294-bp of the left domain of the mtDNA control region) and chromosomal (C, G and R karyotypes) analyses. Genetic distance between the Guadeloupean racoon and lotor subspecies from Virginia and Maryland was very short (mean sequence divergence between haplotypes equals to 1.46%). A four times higher distance was found between P. l. lotor and P. l. pallidus, a continental subspecies inhabiting Arizona than between P. l. lotor and Procyon minor. A neighbour-joining phenogram is proposed; the Guadeloupean haplotype is on a branch close to the one clustering P. l. lotor from the East coast whereas the haplotype from Arizona diverged earlier. These results strongly suggest that the Guadeloupean racoon is included in the P. lotor species. Moreover, no differences were found between P. lotor and P. minor karyotypes, again suggesting a high genetic homogeneity between the two taxa. Furthermore, comparison of the control region variability within Procyon with intra- and interspecific variability observed in other Carnivores, clearly strengthens the hypothesis that P. minor is conspecific with P. lotor. These results imply that the taxonomic status of the Guadeloupean racoon should be revised. In a biogeographic perspective, it is suggested that the racoon has been recently introduced in Guadeloupe by man with individuals coming from the east coast of the USA. The consequences of these results for conservation of the racoon in Guadeloupe, and more generally, the definition and the use of the subspecies as a unit of conservation are discussed.     

Diet of brown-nosed coatis and crab-eating raccoons from a mosaic landscape with exotic plantations in southern Brazil

We described the diets of two procyonids, the brown-nosed coati Nasua nasua and the crab-eating raccoon Procyon cancrivorus, through analysis of stomach contents of road-killed specimens in southern Brazil. We compared them with previously published dietary information for another syntopic mesopredator, the crab-eating fox Cerdocyon thous. The landscape of the study area includes native grasslands, forests, exotic tree plantations, and other crops. Food items were represented by frequency of occurrence (FO) and relative volume (RV). Stomach contents of 23 coatis were analyzed. Animal and plant items were equally frequent, although the volume of plants was greater. Exotic plant species were consumed more than native plants. Among prey items, invertebrates were more important than vertebrates, mainly because of the frequency of coleopterans and annelids and the volume of necrophagous dipteran larvae. Five specimens of raccoons were analyzed, in which animal items had the highest FO and plant items had the highest RV. Both invertebrate and vertebrate prey had the same FO, although vertebrates had a higher RV. Our data suggest that these procyonids are opportunistic hypocarnivores, utilizing anthropic sources, with diet overlap. The coatis also overlapped their diet substantially with the foxes. The stomach-contents analysis revealed the importance of fruit pulp biomass, soft-bodied animals such as larvae, and also soil, which might indicate feeding habits such as scavenging and geophagy.     

New insights on the geographical origins of the Caribbean raccoons

The introduction of species outside their natural range is one of the major threats to biodiversity and has often been identified as a menace to agricultural production and human health. The raccoon is recognized as a globally invasive species. However, several populations in the Caribbean were long considered native and endemic species. Although previous genetic studies have shown that raccoons from the islands of the West Indies belong to the northern raccoon Procyon lotor, the history and origin of these introductions remain poorly known. In this study, we investigated the geographical origin of Caribbean raccoon populations using newly available molecular genetic data. We used haplotype network analyses of two mitochondrial markers, Cytochrome b and Control Region, with new sequences and those from GenBank. We also specifically investigated the origin of the endangered endemic Cozumel raccoon, Procyon pygmaeus, by re-analyzing data. Our results confirmed that all Caribbean raccoon populations belong to the northern raccoon. Bahamian populations originated from two different sources in Florida, and the Lesser Antilles raccoons seem to originate from northern regions of the native range. In addition, our results question the taxonomic status of the Cozumel raccoon, as currently available genetic data support a conspecific status with the northern raccoon. These results have important implications in the context of conservation and ecosystem management. Identifying origins of introduced populations and understanding the history of their introductions will facilitate studies on the impact of the raccoon on insular ecosystems.     

Survival and Body Condition of Raccoons at the Edge of the Range

ABSTRACT We investigated the influence of intrinsic and extrinsic variables on overwinter survival of raccoons (Procyon lotor; n = 114) at the northern edge of their distribution. A Cox proportional hazard model identified winter severity as the variable with the greatest influence on raccoon survival (β = 1.08). Autumn body condition estimates (20.5 ± 0.46% total body fat) were relatively stable across years even though we observed large differences in autumn food indices. Variations in autumn body condition did not explain heterogeneity observed in overwinter survival nor the spring condition in which raccoons emerged. Relatively constant autumn body condition suggests reliable availability of anthropogenic food resources may negate variations observed in natural food items on which raccoons rely during hyperphagia. Conversely, spring body condition did vary among years and was highly correlated with winter severity. Accordingly, we also observed a strong inverse relationship with overwinter survival and winter severity. Our findings indicate winter climatic constraints are important factors governing the northern limit of raccoon distribution and changes in winter severity could have important implications in further range expansion of this species.     

Combining direct and indirect genetic methods to estimate dispersal for informing wildlife disease management decisions

Epidemiological models are useful tools for management to predict and control wildlife disease outbreaks. Dispersal behaviours of the vector are critical in determining patterns of disease spread, and key variables in epidemiological models, yet they are difficult to measure. Raccoon rabies is enzootic over the eastern seaboard of North America and management actions to control its spread are costly. Understanding dispersal behaviours of raccoons can contribute to refining management protocols to reduce economic impacts. Here, estimates of dispersal were obtained through parentage and spatial genetic analyses of raccoons in two areas at the front of the raccoon rabies epizootic in Ontario; Niagara (N = 296) and St Lawrence (N = 593). Parentage analysis indicated the dispersal distance distribution is highly positively skewed with 85% of raccoons, both male and female, moving < 3 km. The tail of this distribution indicated a small proportion (< 4%) moves more than 20 km. Analysis of spatial genetic structure provided a similar assessment as the spatial genetic correlation coefficient dropped sharply after 1 km. Directionality of dispersal would have important implications for control actions; however, evidence of directional bias was not found. Separating the data into age and sex classes the spatial genetic analyses detected female philopatry. Dispersal distances differed significantly between juveniles and adults, while juveniles in the Niagara region were significantly more related to each other than adults were to each other. Factors that may contribute to these differences include kin association, and spring dispersal. Changes to the timing and area covered by rabies control operations in Ontario are indicated based on these dispersal data.     

Hardwood management and restoration of longleaf pine ecosystems may affect raccoon daytime resting sites

Fire‐maintained Pinus palustris (longleaf pine) ecosystems are species rich and considered a top conservation priority in the southeastern United States. Ground‐nesting species such as Gopherus polyphemus (gopher tortoise) and Colinus virginianus (northern bobwhite) thrive in longleaf ecosystems. However, the generalist carnivore Procyon lotor (raccoon) is a significant predator of these endemic ground nesters. In forested ecosystems, raccoons prefer hardwood‐dominated habitats. Removal of hardwood trees, which is a common longleaf pine ecosystem restoration tool, affects habitat use of this predator. We examined 269 daytime resting sites (DRS) associated with 31 radio‐collared adult raccoons (18 M, 13 F) during 2014–2015 on a longleaf pine‐dominated site in southwestern Georgia. We developed 26 a priori models using an information theoretic approach to evaluate factors affecting use of DRS by raccoons. The top two models (ΔAIC < 2) had combined model weights of 0.75 and contained tree diameter, tree type, presence of nearby hardwood, and distances to pine, hardwood, mixed forest, and agriculture as predictors. However, the only informative variables were tree type and tree diameter. Raccoons used DRS in all available forest types, but were less likely to use pine trees (n = 7) relative to hardwoods (n = 247), and there was a positive relationship with tree diameter. Females used smaller trees farther from agriculture and primary roads, and were closer to wetlands than those used by males. Hardwood removal from within longleaf pine ecosystem affects habitat use of this predator, specifically DRS.