Introduction

Pheromones in the form of scent marks have a particularly important role in the territorial behaviour of mammals and other terrestrial vertebrates including lizards and salamanders. Territories can be broadly defined as defended areas (Stamps 1994). They are often for feeding, but can include other resources such as a den site, which is valuable for the owner or for attracting mates. Depending on the species, the territory might be owned by one male, such as a small antelope, or by a group, as in badgers. Many social insects are also fiercely territorial but they generally use scent marks in different ways from vertebrates (Box 5.1).

Pheromone or scent marking is one of the most conspicuous behaviours of many mammals. Mammals have an enormous variety of specialised scent glands but a common pattern of scent marking: glandular secretions, and often faeces and urine, are placed at conspicuous places in their home ranges or territories, often in lines along paths or boundaries (Fig. 5.1) (Gosling & Roberts 2001). Males tend to mark more than females, and dominant males or territory holders mark more than others. Scent marking forms a central part of many ritualised contests between territorial males or between competing groups, for example ‘stink fights’ between neighbouring groups of ring-tailed lemurs (Fig. 5.2).

One benefit of scent marks comes from the unique separation of signaller and signal: unlike other signals, pheromones ‘shout’ even when the animal is not there. However, while producing pheromones takes less energy than sound signals, scent marking nonetheless can involve significant costs in time and risk.