Food and Energy Use by Captive Coyotes

Litvaitis, John A.; Mautz, William W.

doi:10.2307/3808350

Cited by 36 publications

(28 citation statements)

References 11 publications

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“…This estimate of 1.75 kcal/g for animals has been empirically confirmed for snowshoe hares. Captive coyotes obtained 1.4 kcal/g FW of metabolizable energy from snowshoe hares (Litvaitis and Mautz 1980), which is equivalent to 80% of 1.75 kcal/g. To account for migration and hibernation, we multiplied feeding rates of ground squirrels and migratory avian predators and songbirds by one-third because these species are active at Kluane for only 4 months of the year.…”

Section: Consumption Per Biomass (Q/b)mentioning

confidence: 96%

Mass-Balance Analyses of Boreal Forest Population Cycles: Merging Demographic and Ecosystem Approaches

Ruesink

Hodges

2002

Ecosystems

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Using Ecopath, a trophic mass-balance modeling framework, we developed six models of a Canadian boreal forest food web centered around snowshoe hares, which have conspicuous 10-year population cycles. Detailed models of four phases of the cycle were parameterized with long-term population data for 12 vertebrate taxa. We also developed five other models that, instead of observed data, used parameter values derived from standard assumptions. Specifically, in the basic model, production was assumed to equal adult mortality, feeding rates were assumed to be allometric, and biomass was assumed to be constant. In the actual production, functional response, and biomass change models, each of these assumed values from the basic model was replaced individually by field data. Finally, constant biomass models included actual production by all species and functional responses of mammalian predators and revealed the proportion of herbivore production used by species at higher trophic levels. By comparing these models, we show that detailed information on densities and demographics was crucial to constructing models that captured dynamic aspects of the food web. These detailed models reinforced an emerging picture of the causes and consequences of the snowshoe hare cycle. The snowshoe hare decline and low phases were coincident with times when per capita production was relatively low and predation pressure high. At these times, ecotrophic efficiencies (EE) suggest there was little production that remained unconsumed by predators. The importance of both production and consumption implies that bottom-up and top-down factors interacted to cause the cycle. EEs of other herbivores (ground squirrels, red squirrels, small mammals, small birds, grouse) were generally low, suggesting weak top-down effects. Predation rates on these "alternative" prey, except ground squirrels, were highest when predators were abundant, not when hares were rare; consequently, any topdown effects reflected predator biomass and were not a function of diet composition or functional responses. Finally, several predators (lynx, coyotes, great-horned owls) showed clear bottom-up regulation, reproducing only when prey exceeded threshold densities. Taken altogether, these results demonstrate that ecosystem models parameterized by population data can describe the dynamics of nonequilibrial systems, but only when detailed information is available for the species modeled.

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Section: Consumption Per Biomass (Q/b)mentioning

confidence: 96%

Mass-Balance Analyses of Boreal Forest Population Cycles: Merging Demographic and Ecosystem Approaches

Ruesink

Hodges

2002

Ecosystems

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“…Previous studies [Kaufman and Kaufman, 1977;Bird and Ho, 1976;Litvaitis and Mautz, 1980] found that the crude protein levels in adult mice of four species range from about 55% to 63% of DM, whereas crude fat ranges from 19% to 24%. Our mice were somewhat fatter, containing 22-32% crude fat, which suggests that they were either still growing (juvenile mice contain a higher fat content compared to adults [Dierenfeld et al, 2002]) or were not food-limited.…”

Section: Nutrient Datamentioning

confidence: 99%

“…A number of studies have reported the proximate and mineral content of mice and rats fed to captive animals [Bird and Ho, 1976;Kaufman and Kaufman, 1977;Litvaitis and Mautz, 1980;Dierenfeld et al, 1996;Clum et al, 1996]. The vast majority of specimens analyzed were born and raised in a controlled environment, and fed commercially manufactured rodent diets.…”

Section: Introductionmentioning

confidence: 99%

Proximate, vitamins A and E, and mineral composition of free‐ranging cotton mice (Peromyscus gossypinus) from St. Catherines Island, Georgia

2004

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Although rodents are an integral part of numerous carnivore diets, there is little published information regarding nutrient composition in free-ranging mice for comparison with laboratory-reared prey. Cotton mice (Peromyscus gossypinus, n ¼ 6) were captured on St. Catherines Island, Georgia, and analyzed for water, ash, protein, and fat content (proximate constituents), as well as minerals and the fatsoluble vitamins A and E. The overall body composition (mean7SD: 65.8%71.9% water, 10.9%72.2% ash, 56.4%74.1% protein, and 27.2%73.9% fat) was similar to published values for adult laboratory mice (Mus domesticus). The macro-(Ca, K, Mg, Na, and P) and trace (Cu, Fe, Mn, and Zn) mineral levels were also similar to previously reported values for laboratory mice, and in general met or exceeded the established nutrient requirements for domestic carnivores. Vitamin E ranged from 77 to 170 IU/kg dry matter (DM) in these mice-again, similar to values previously quantified in laboratory mice. However, the vitamin A concentrations (21,94776,893 IU/kg DM) in the free-ranging mice were consistently and substantially lower than values reported for whole laboratory mice. To our knowledge, this is the first quantification of vitamin A in free-ranging mice used as prey by carnivores. While other nutrients measured were similar between captive-reared and free-ranging mice, the current data suggest the need for further investigation of vitamin A nutrition in the development of optimal diets for carnivores in captivity.

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“…Many carnivorous mammals commonly ingest fleshy fruits (Gittleman 1989). Nevertheless, the role of fruits on carnivore nutritional ecology and energetics has remained virtually unexplored (Vogtsberger & Barret 1973, Moors 1977, Litvaitis & Mautz 1980, Ball & Golightly 1992, McNab 1995, Welch et al 1997.…”

mentioning

confidence: 99%

Nutritional ecology and digestive response to dietary shift in the large South American fox, Pseudalopex culpaeus

Silva

Jaksic

Bozinovic

2005

Rev. chil. hist. nat.

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We tested the role of dietary shifts (from rodents to fruits and to mixed diets) on the nutritional ecology of the culpeo fox Pseudalopex culpaeus, a native canid of South America. We studied the effects of food quality on digestive processes, nutrition, and mass balance, and the implications of diet quality for fox survival. We observed at the end of the nutritional trials that body mass differed significantly between the three diet groups (fruits, rats and mixed diets), while percentage of body mass change differed significantly only in the fruit diet treatment. Foxes fed with fruits consumed more food to meet their dietary and metabolic needs. Across diets, dry-matter as well as energy digestibility increased significantly with diet quality. Also, mean retention time was negatively and significantly correlated with dry-matter intake. We put forth that mixed diet may yield higher assimilation efficiencies and hence higher nutrient intakes than those predicted from the ingestion and assimilation of pure diets (i.e,. only rats, only fruits). We hypothesize that during periods of low availability of mammalian prey, a mixed diet should yield a positive energy/mass balance for the fox. We conclude that temporal and spatial variation in nutrient, energy, and water contents of prey available in a given habitat could have an important effect on fox nutrition, energy use, and mass balance. Finally, we postulate that P. culpaeus could not survive on fruits only past seven days.Key words: nutritional bottleneck, fox, dietary shift, fruit consumption. RESUMENSometimos a prueba el papel del cambio de dieta (desde roedores a frutos y dieta mixta) sobre la ecología nutricional del zorro culpeo Pseudalopex culpaeus, especie nativa de Sudamérica. Estudiamos el efecto de la calidad del alimento sobre los procesos digestivos, nutrición, balance de masas y las implicancias de la calidad de la dieta sobre la sobrevivencia de los zorros. La masa corporal al final de los ensayos nutricionales difirió significativamente entre los tres grupos de dietas (frutos, ratas y dieta mixta), en tanto que el porcentaje de cambio en masa corporal solo fue significativo en el caso de la dieta de frutos. Los zorros alimentados con frutos consumieron más alimento para satisfacer sus necesidades dietarias y metabólicas. Tanto la ingesta de materia seca como la digestibilidad se incrementaron significativamente con la calidad de la dieta. Más aún, el tiempo de retención promedio estuvo negativa y significativamente correlacionado con la ingesta de materia seca. Pensamos que la dieta mixta puede entregar mayores eficiencias de asimilación y por lo tanto mayores ingestas de nutrientes que lo predicho por la ingesta y asimilación de dietas puras (i.e., solo ratas, solo frutos). Proponemos la hipótesis que durante períodos de baja disponibilidad de presas (micromamíferos) una ingesta de dieta mixta podría entregar un balance energía/masa positivo para los zorros. Concluimos que la variación temporal y espacial de nutrientes, energía y contenido d...

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Food and Energy Use by Captive Coyotes

Cited by 36 publications

References 11 publications

Mass-Balance Analyses of Boreal Forest Population Cycles: Merging Demographic and Ecosystem Approaches

Mass-Balance Analyses of Boreal Forest Population Cycles: Merging Demographic and Ecosystem Approaches

Proximate, vitamins A and E, and mineral composition of free‐ranging cotton mice (Peromyscus gossypinus) from St. Catherines Island, Georgia

Nutritional ecology and digestive response to dietary shift in the large South American fox, Pseudalopex culpaeus

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