Comparison of Techniques for Estimating Age in Raccoons

Fiero, Brad C.; Verts, B. J.

doi:10.2307/1380894

Cited by 16 publications

(10 citation statements)

References 4 publications

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“…In a study comparing five techniques for estimating age in raccoons, accuracy based on pair-wise comparisons of aging methods for animals up to 4-years old varied from 31 to 100% (Fiero & Verts 1986). Therefore, age estimates for coatis and foxes provided by our method are at least as accurate as those offered by other methods for other carnivore species.…”

Section: Mean Number Of Correct Classificationsmentioning

confidence: 83%

Estimating age of carnivores from the Pantanal region of Brazil

Olifiers

Bianchi²,

D’Andrea

et al. 2010

Wildlife Biology

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Conservation and management of animal populations often require knowledge about the age structure, but this information is usually difficult to discern. We propose a method to estimate the age of carnivores based on dental condition and body size measurements, and we apply the method to populations of brown‐nosed coatis Nasua nasua and crab‐eating foxes Cerdocyon thous in the Brazilian Pantanal. We sexed, weighed and measured 31 coatis and 45 foxes of known‐age, and characterized and quantified their pattern of dental eruption and wear for the construction of a teeth condition index. Scores of the first factors of a principal component analysis including data on six body size measurements and the teeth condition index of the individuals were then used in a discriminant analysis to generate functions that can be used for estimating age of animals of unknown age. Models were validated using subsets of individuals of known age through a 3‐fold cross validation process. The first functions accounted for over 90% of the discriminatory power for both species. Whereas in coatis, the first function was mainly explained by the body size measurements, in crab‐eating foxes it was represented mainly by the teeth condition index. During model validation, individuals were on average classified with 88 and 80% average confidence for coatis and foxes, respectively. Our method is as accurate as other methods that are commonly applied to assess age, but less subjective. While it requires animal capturing, it is less invasive than methods requiring tissue removal such as analyses of teeth cementum annuli. The method we outlined can be used for age estimation of other populations, as long as the models are validated with a subset of animals from the region studied. It could also be useful as a model for estimating age of other carnivore species.

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Section: Mean Number Of Correct Classificationsmentioning

confidence: 83%

Estimating age of carnivores from the Pantanal region of Brazil

Olifiers

Bianchi²,

D’Andrea

et al. 2010

Wildlife Biology

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“…Animals in bad conditions as well as juveniles and lactating females were not handled but released immediately. Adult animals were defined by body weight (Fiero and Verts 1986;Stubbe 1989;Wandeler and Lüps 1993), putting the transfer box on a mobile scale. If animals were heavy enough, they were immobilized with an intramuscular injection of a ketamine-xylazine hydrochloride combination via a blowpipe.…”

Section: Live-trapping and Radio Trackingmentioning

confidence: 99%

Spatial interrelations between raccoons (Procyon lotor), red foxes (Vulpes vulpes), and ground-nesting birds in a Special Protection Area of Germany

2019

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In this study, we examine the spatial interrelation between different carnivore species (Carnivora, Mammalia) and ground-nesting birds in a Special Protection Area (SPA) in Brandenburg, Germany. Camera-and live-trapping of carnivores during an 18-month period revealed that the SPA hosts most mesocarnivore species that occur in Germany. Since raccoon (Procyon lotor), red fox (Vulpes vulpes), and domestic cat (Felis silvestris f. catus) showed highest abundance-activity indices, we used GPS telemetry for a detailed analysis of spatial behavior of nine raccoons and five red foxes over a 22-month period. Spatial distribution patterns showed a strong difference between both species: raccoons showed a clear preference for reed swamps and shrub swamps, clustering in high concentrations along the edges of water bodies. Although this behavior is likely due to the high and year-round availability of aquatic food sources, overlap of raccoon core areas with high densities of wetland birds likely results in a high level of sublethal predation effects particularly on waterfowl breeding in reed beds. Red foxes showed much more evenly distributed movement patterns and a high intraspecific variability in habitat preference, revealing a general preference for woodlands and an avoidance of wetlands. Thus, predation pressure by foxes on ground-breeders seems to be lower and focusing on grasslandassociated bird species in close proximity to woodlands. Consequently, our study highlights the need for a differentiated view on the predatory potential of particular mesocarnivore species on the endangered bird species in the SPA, leading to future management implications with a focus on swampland habitats.

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“…The method is useful only up to 10-13 months of age and only in male animals. Recent studies suggest the presence of darkly stained adhesion lines in the mandible of various mammals is a method of promise, although there are some animals that show no such lines and are known to be the young of the previous year (Costain & Verts, 1982;Fiero & Verts, 1986;Livezely & Verts, 1979;Sullins, et al, 1976). Although these methods are useful for differentiating between juveniles and adults, they are not sufficient to separate animals into more than these two age classes.…”

Section: Age Determinationmentioning

confidence: 99%

Studies of ecological factors that affect the population and distribution of the western gray squirrel in northcentral Oregon

Foster¹

2000

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Comparison of Techniques for Estimating Age in Raccoons

Cited by 16 publications

References 4 publications

Estimating age of carnivores from the Pantanal region of Brazil

Estimating age of carnivores from the Pantanal region of Brazil

Spatial interrelations between raccoons (Procyon lotor), red foxes (Vulpes vulpes), and ground-nesting birds in a Special Protection Area of Germany

Studies of ecological factors that affect the population and distribution of the western gray squirrel in northcentral Oregon

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