Predator size and prey size–gut capacity ratios determine kill frequency and carcass production in terrestrial carnivorous mammals

Abstract

Carnivore kill frequency is a fundamental part of predator–prey interactions, which are important shapers of ecosystems. Current field kill frequency data are rare and existing models are insufficiently adapted to carnivore functional groups. We developed a kill frequency model accounting for carnivore mass, prey mass, pack size, partial consumption of prey and carnivore gut capacity. Two main carnivore functional groups, small prey‐feeders versus large prey‐feeders, were established based on the relationship between stomach capacity (C) and pack corrected prey mass (iMprey). Although the majority of small prey‐feeders is below, and of large prey‐feeders above a body mass of 10–20 kg, both occur across the whole body size spectrum, indicating that the dichotomy is rather linked to body size‐related ecology than physiology. The model predicts a negative relationship between predator size and kill frequency for large prey‐feeders. However, for small prey‐feeders, this negative relationship was absent. When comparing carnivore prey requirements to estimated stomach capacity, small carnivores may have to eat to their full capacity repeatedly per day, requiring fast digestion and gut clearance. Large carnivores do not necessarily have to eat to full gastric capacity per day, or do not need to eat every day, which in turn reduces kill frequencies or drives other ecological processes such as scavenging, kleptoparasitism, and partial carcass consumption. Where ecological conditions allow, large prey‐feeding appears attractive for carnivores, which can thus reduce activities related to hunting. This is particularly so for large carnivores, who can achieve distinct reductions in hunting activity due to their relatively large gut capacity.

Early Pleistocene faunivorous hominins were not kleptoparasitic, and this impacted the evolution of human anatomy and socio-ecology

“…If meat-eating allowed for a high-quality diet impacting on higher hominin demographics, hominin expanding densities across landscapes could have pressured several competing carnivores and could have placed the latter at selective disadvantage. Such a demographic increase is also supported by much bigger sizes of Acheulian sites after 1.7 Ma and the conspicuous evidence of megafaunal exploitation (not necessarily through hunting) after this date by hominins, probably suggesting bigger group sizes 36 , 38 , 39 , given the ecological correlation between carcass size exploitation and number of carnivore commensals 80 – 84 . Body-size ecology (including total carnivore mass and pack size) determines targeting specific prey sizes in mammalian predators 80 – 84 .…”

“…Such a demographic increase is also supported by much bigger sizes of Acheulian sites after 1.7 Ma and the conspicuous evidence of megafaunal exploitation (not necessarily through hunting) after this date by hominins, probably suggesting bigger group sizes 36 , 38 , 39 , given the ecological correlation between carcass size exploitation and number of carnivore commensals 80 – 84 . Body-size ecology (including total carnivore mass and pack size) determines targeting specific prey sizes in mammalian predators 80 – 84 . The increase of hominin body size and anatomical robustness across the early and middle Pleistocene indicates a selection of physical strength, probably either reflecting predatory strategies that required force or an exaptation in this direction.…”

The dynamics of spawning acts by a semelparous fish and its associated energetic costs

“…Pelster 2015). This illustrates the potentially broad application of our acceleration-based approached, which, once refined, could be used to detect the many ecologically or behaviourally relevant changes in animal shape beyond slimming due to energy consumption, such as parturition, massive food intake in large predators (Cuyper et al 2019), inflammatory swelling (Duncan et al 2016), or inflation as a courtship or defence behaviour (Wainwright and Turingan 1997). Combined with dynamic acceleration, such data could be used to test whether these changes in shape are associated to global activity or to the expression of specific behaviours.…”

Canine Diet

“…Such dietary flexibility is also a survival advantage in changing environmental circumstances and in part likely accounts for the wide geographical distribution of canids. Many smaller species will undertake solitary hunting/scavenging behaviors and ingest to gut capacity, whereas larger species will have reduced frequency of predation, mitigated by both digestive system capacity and prey size (De Cuyper et al 2019).…”