Scavenging by vertebrates: behavioral, ecological, and evolutionary perspectives on an important energy transfer pathway in terrestrial ecosystems

Abstract

Carrion use by terrestrial vertebrates is much more prevalent than conventional theory implies, and, rather than a curiosity of animal behavior, is a key ecological process that must be accounted for. Human aversion to rotted substances and difficulties associated with identifying scavenged material in studies of food habits have contributed to the relative lack of information concerning scavenging behavior in vertebrates. Several lines of evidence, however, suggest that carrion resources are more extensively used by vertebrates than has been widely assumed: 1) a substantial number of animals die from causes other than predation and become available to scavengers, 2) a wide variety of vertebrate scavengers, rather than microbes or arthropods, consume most available carcasses, and 3) intense competition exists between vertebrate scavengers and decomposers, especially in warm climates. Although vultures are best adapted to use carrion, nearly all vertebrate predators are also scavengers to some extent. The costs and benefits associated with carrion use influences the evolution of scavenging behavior in vertebrates, resulting in a continuum of facultative scavengers that use carrion to varying degrees. The realized usage of carrion by a vertebrate species is influenced by the speed and efficiency with which it forages, its visual and olfactory abilities, and its capacity for detoxifying products of decomposition. A deeper understanding of carrion use by facultative scavengers will improve our knowledge of community and ecosystem processes, especially the flow of energy through food webs.

Microbial decomposition of skeletal muscle tissue (Ovis aries) in a sandy loam soil at different temperatures

“…Numerous studies have been conducted in order to examine decomposition processes associated with plant-derived organic residues (Chander and Brookes,cadavers and cadaver components (e.g. skeletal muscle tissue, hair, bone) although animals regularly die in terrestrial ecosystems (DeVault et al, 2003). Of these studies, the vast majority are concerned with the activity of arthropods (e.g.…”

Scavenging on sea turtle carcasses by multiple Jaguars in northwestern Costa Rica

“…As a result, most large mammalian carnivores shift facultatively between hunting and scavenging depending on seasonal and regional variation of prey availability (Wilmers et al 2003;Wilson and Wolkovich 2011;Pereira et al 2013). A clearer perspective on carrion use by mammalian carnivores will improve our understanding of critical ecological processes, particularly those associated with energy flow and trophic interactions between individuals and species (DeVault et al 2003).…”

“…Mammalian carnivores are traditionally labeled as predators, but they do not usually pass by opportunities to consume carcasses when encountered (DeVault et al 2003;Selva et al 2005;Wilson and Wolkovich 2011). No mammals have evolved into obligate scavengers and even the most well adapted mammalian scavengers, such as hyenas, kill the majority of their food (Cooper et al 1999).…”

“…By definition, scavengers feed on the remains of animals that have died (i. e. carrion), while predators kill animals in order to feed on the resulting carcasses . The carcasses can be consumed by an individual or shared by several individuals, depending on the behavior of the species and the abundance and availability of the prey and carcasses (DeVault et al 2003;Wilson and Wolkovich 2011;Pereira et al 2013). One of the challenges faced by most mammalian carnivores is to secure a regular supply of food, especially if the natural susceptibility of animals to die or to be killed varies seasonally and spatially (DeVault et al 2003).…”

“…The carcasses can be consumed by an individual or shared by several individuals, depending on the behavior of the species and the abundance and availability of the prey and carcasses (DeVault et al 2003;Wilson and Wolkovich 2011;Pereira et al 2013). One of the challenges faced by most mammalian carnivores is to secure a regular supply of food, especially if the natural susceptibility of animals to die or to be killed varies seasonally and spatially (DeVault et al 2003). As a result, most large mammalian carnivores shift facultatively between hunting and scavenging depending on seasonal and regional variation of prey availability (Wilmers et al 2003;Wilson and Wolkovich 2011;Pereira et al 2013).…”