Different Forms of Vigilance in Response to the Presence of Predators and Conspecifics in a Group-Living Mammal, the European Rabbit

Authors


Raquel Monclús, Unidad de Zoología, Dpto. Biología, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
E-mail: raquel.monclus@uam.es

Abstract

In group-living mammals, the major functions of vigilance are to detect the presence of predators and to monitor the movements of conspecific competitors, i.e. of potential opponents in agonistic encounters. The minimum distance to such a conspecific competitor that an animal considers safe is usually lower than to a predator, whereas the frequency of encounters with conspecifics is higher. Therefore, the acquisition of information about a predator or about a conspecific could lead to the existence of at least two different modes of vigilance behaviour. The aim of the present study was to describe and compare different forms of vigilance behaviour that European rabbits, Oryctolagus cuniculus, display in anti-predator and social contexts. We conducted an observational study on individually marked animals from a field enclosure population. We recorded social interactions of the animals, the presence of aerial predators (common buzzard Buteo buteo), and the vigilance behaviour of the rabbits. We distinguished between two forms of vigilance of different intensity: subtle and overt. The frequencies of both forms of vigilance displayed by the rabbits differed significantly in occurrence, duration, and distribution over time. Females and males showed higher frequencies of overt but not subtle vigilance when buzzards were present. In contrast, the presence of conspecifics in close proximity affected the display of subtle but not overt vigilance: males increased the frequency of subtle vigilance when other males were close. Females increased subtle vigilance in proximity of males and females; however, this effect was only apparent in females with a more unstable social situation. In conclusion, European rabbits differentially increased two different forms of vigilance behaviour in social and anti-predator contexts.

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