Spatial positioning of individuals in a group of feral horses: a case study using drone technology

Abstract

Spatial positioning of individuals in animal groups has been studied from numerous perspectives. However, although many studies have focused on spatial position in flocks of birds and schools of fish, relatively few studies have been conducted in mammals with high accuracy. Because some mammal species form societies, we wondered how social relationships among mammals within a group influence each individual’s spatial position. To address this issue, we used drones to obtain accurate positioning of individuals in a feral horse group on the Serra D’ Arga mountain in Portugal. The results of our study revealed the following characteristics: (1) the male in between social and spatial relationships indicated that they are independent from each other. The present study is the first to reveal the characteristics of spatial positioning in a mammalian group using drone technology. The harem group was located in the periphery; (2) as in other species, individuals had areas of repulsion and attraction, and (3) nearest neighbors were located more toward the sides than to the back or front. We also measured the social relationships between individuals in terms of grooming frequency. Social network analyses of the correlation between social and spatial relationships indicated that they are independent from each other. The present study is the first to reveal the characteristics of spatial positioning in a mammalian group using drone technology.