When prey provide more than food: mammalian predators appropriating the refugia of their prey

Abstract

Some mammalian predators acquire both food and shelter from their prey, by eating them and using the refugia the prey construct. I searched the literature for examples of predators that exhibit this behavior and summarize their taxonomic affiliations, relative sizes, and distributions. I hypothesized that size ratios of species involved in this dynamic would be near 1.0, and that most of these interactions would occur at intermediate and high latitudes. Seventeen species of Carnivorans exploited at least 23 species of herbivores as food and for their refugia. Most of them (76.4 %) were in the Mustelidae; several small species of canids and a few herpestids were exceptions. Surprisingly, the average predator/prey weight ratio was 10.51, but few species of predators were more than ten times the weight of the prey whose refugia they exploit. This may be why the long and thin Mustelines commonly exploit this habit. A number of predators appropriate the refugia of their key prey during winter when their prey occupies thermally secure nests. Indeed, most of the predator–prey pairs that engage in this relationship occur in intermediate and high latitudes, though there may be a reporting bias. Predators that depend on prey as food and for shelter, and whose fates are linked strongly to a few key prey species, may be particularly vulnerable to changes in climate that affect the subnivean habitats of their prey. Mammals that create refugia that can be used by other species (among them predators) may play disproportionately important roles in their communities.