A recipe for scavenging in vertebrates – the natural history of a behaviour

Abstract

Despite its prevalence, the importance of scavenging to carnivores is difficult to ascertain in modern day forms and impossible to study directly in extinct species. Yet, there are certain intrinsic and environmental features of a species that push it towards a scavenging lifestyle. These can be thought of as some of the principal parameters in optimal foraging theory namely, encounter rate and handling time. We use these components to highlight the morphologies and environments that would have been conducive to scavenging over geological time by focusing on the dominant vertebrate groups of the land, sea and air. The result is a synthesis on the natural history of scavenging. The features that make up our qualitative scale of scavenging can be applied to any given species and allow us to judge the likely importance of this foraging behaviour

The mesoscavenger release hypothesis and implications for ecosystem and human well‐being

“…It may be true that facultative scavengers reduce their search efficiency for carrion when carrion densities are low, and alternatively increasingly target live prey if more available, which is consistent with optimal foraging theory (Kane et al . ; Margalida et al . ).…”

Understanding how mammalian scavengers use information from avian scavengers: cue from above

“…The resulting population sizes were then halved because (i) vultures tend not to forage everyday especially during the breeding season where they exhibit biparental care (Mundy ) and (ii) the other species tend to be facultative rather than obligate scavengers (Kane et al . ). Given that the eagle numbers are extrapolated from transect counts, which may be biased by transient individuals, we ran each model again with half the predicted population for eagles (40 instead of 80).…”

“…Dominance was sized-based and the hierarchy from most dominant to least dominant was hyena, jackal, LFV, AWBV, eagle (Attwell 1963;Kendall 2013;Kruuk 1967;Mundy 1992 (Mundy 1992) and (ii) the other species tend to be facultative rather than obligate scavengers (Kane et al 2016). Given that the eagle numbers are extrapolated from transect counts, which may be biased by transient individuals, we ran each model again with half the predicted population for eagles (40 instead of 80).…”

The zooarchaeology and paleoecology of early hominin scavenging

“…Indeed, most large mammalian carnivores shift facultatively between hunting and scavenging depending on the regional, seasonal, and spatial variation in the susceptibility of their prey to mortality . Scavenging opportunities are dependent on the density, size, and quality of carcasses encountered, and species that rely on scavenging to sustain a significant portion of their diets must encounter enough carrion to meet their dietary needs . The encounter rate is in turn dependent on the ecology of the local carnivore and herbivore populations including carnivore species density and degree of sociality, carnivore feeding preferences and specializations, predator to prey ratios, and prey biomass and densities .…”

“…In fact, Bickerton and Szathmáry suggested that language and cooperation on a human scale are so distinct from behaviors in other primates that they required a trigger of some kind—and they suggest the only activity practiced by hominins that contained all the necessary components for that trigger was confrontational scavenging . The emergence of endurance running has even been proposed as an adaptation to securing sufficient access to scattered and ephemeral carcasses, or to signal the location of carrion to others, although this behavior is more often linked to hunting live prey …”