Models of Optimal Size for Solitary Predators

Abstract

Models are presented which predict an optimal size, defined as that size which takes the least amount of time to satisfy its energy requirements, for several types of predators: I-predators which expend no time or energy in food search alone and which pursue their prey over varying distances; II-predators which expend time and energy while searching for items but none in pursuit; IIa and IIb-predators which expend time and energy both in search and pursuit. All predators are assumed to expend time and energy in handling and swallowing prey. In the simplest models considered, equations are constructed which combine to produce three major properties: (a) larger predators expend more energy in pursuing an item over a given distance than do smaller ones; (b) for most prey items, larger animals expend less time and for somewhat fewer items less energy in handling and swallowing than do smaller predators; (c) time and to a lesser extent energy lost while searching between two items are often not very different ...