The largest existing carnivore, the polar bear, is only around half a ton, while the largest known extinct carnivores, such as the short-faced bear, weighed around one ton. Thus, mammalian carnivores are relatively small compared with the largest extinct terrestrial herbivorous mammals, such as the Indricothere, which weighed around 15 tons. Analyzing the balance between energy intake and expenditure across a range of species, we predict that mammalian carnivores should have a maximum body mass of one ton. While carnivores around the size of a lynx or larger can obtain higher net energy intake by switching to relatively large prey, the difficulty of catching and subduing these animals means that a large-prey specialist would expend twice as much energy as a small-prey specialist of equivalent body size. Our approach provides a framework for understanding carnivore energetics, size, and extinction dynamics.Ĭarnivores fall into two dietary groups based on the energetic requirements of their feeding strategies: small-bodied species, which feed mostly on prey smaller than themselves, and large-bodied species, which prefer prey around their own size. Given predictions of expenditure and estimates of intake, we predict a maximum carnivore mass of approximately a ton, consistent with the largest extinct species. This suggests that carnivores at the upper limits of each group are constrained by intake and adopt energy conserving strategies to counter this. However, when each dietary group is considered individually they both display a shallower scaling. Across all species, energy expenditure and intake both follow a three-fourths scaling with body mass. However, because it requires more energy to pursue and subdue large prey, this leads to a 2-fold step increase in energy expenditure, as well as increased intake. We show that the transition from small to large prey can be predicted by the maximization of net energy gain larger carnivores achieve a higher net gain rate by concentrating on large prey. We develop a model that predicts the mass-related energy budgets and limits of carnivore size within these groups. In the analysis of each of these issues-and the role water plays in the overall economy, CGE models have made an important contribution to understanding and informed policymaking.Mammalian carnivores fall into two broad dietary groups: smaller carnivores (20 kg) that specialize in feeding on large vertebrates. Such issues range from aquaculture through pricing of water to virtual water-and many points in between. Considerations of environment and environmental regulation, inevitably involve a consideration of issues to do with water. More recently, the areas of environmental economics and regulation has attracted the attention of CGE modelers. This is particularly true of issues to do with tax and tariff reform, where CGE models first gained prominence. Many areas of economic analysis, reform, and policymaking have benefitted from scrutiny in a CGE context. The aim is to empirically solve for equilibrium demand, supply, and price levels across the markets in the economy. Computable general equilibrium (CGE) models add to this abstract point of view by calibrating models of the economy using actual economic data. General equilibrium theory thinks of the economy as a collection of interconnected markets, each of which, in isolation and in combination, is driven toward some sort of equilibrium. Scarcity of Water for Agriculture: A Case Study for China.Water Scarcity, Poverty, and Unequal Distribution of Income.Double (and Triple) Dividend Hypotheses.Economic Impacts of Hydrological Change.Case Study: Yellow River Irrigation District, China.An Overview of Multisectoral Water-Economy Interactions.Some Early Motivation for the Construction of WCGE Models.
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