The Rum Goats
The Rum Goat Project was started in 1980 and has run intermittently since then (continuously since 2000). The main focus of the project has been on population regulation, and in particular the ways in which the animals cope with both the thermal costs of living at high latitudes and the disruptive effects of the summer rut. In addition, we have been particularly interested in modeling male mating strategies and the fission-fusion aspects of social grouping.
The behaviour and population dynamics of the feral goats living on the Isle of Rum are interesting as they present the opportunity to study how a population of originally tropical mammals have adapted to persist in an extreme temperate environment.
It is not known exactly how or when goats first came to be on the island but the most widely accepted and feasible explanation is that they were brought to the island as domestic stock some time before the highland clearances in 1828. It is thought that domestic goats of the people living on Rum at that time may have been left behind after the clearances and that they are the ancestors of the feral goats present on the island today. The goats are thought to have been free ranging on Rum for at least 200 years and yet have failed to colonise inland areas of the island in the way that the red deer population have done. The feral goats on the Isle of Rum today are confined to the steep cliffs along the coastline of the island from Dibidil to Kilmory (fig 1).
The project is based at Harris in the west of the island. The feral goats on Rum are strongly hefted and the study concentrates on three neighbouring hefts located at different points around the coast line of the island. The study hefts have been named corresponding to their location, these are, Harris, GnP and Wreck Bay (red dots fig 1).
The population of goats on the island at present is believed to be a little over 400 individuals. The number of goats in the study area fluctuates at around 200 individuals from year to year. Each goat in the study area is individually known to the researchers. The goats are not tagged but are easily identified by the differences in coat colour and pattern and horn shape that are widely variable between individuals.
Feral goats are social animals and live in social units known as hefts. These hefts are widely believed to be a matriarchal social organisation although there is no quantitative evidence to support this idea. 
A heft consists of a group of closely associated females and their kids and a similar number of loosely associated males (there tends to be a 1:1 sex ratio). Females are strongly hefted to a particular area although goats are not territorial and therefore do not actively defend these areas. Male goats are also hefted although not as strongly as females and they are known to interact with individuals from other hefts especially during the rut. Females on the other hand do not interact with females from other hefts and very rarely are they found within the home range of a heft that is not their own. Males and females are sexually segregated for most of the year and stick to different areas within the heft range usually only coming together a few months in the year during the rut.
The Rum feral goat project is co-ordinated by Professor Robin Dunbar of the University of Liverpool (evolutionary psychology and behavioural ecology research group) and currently consists of one PhD student and two research assistants.
For further information or to discuss research ideas or volunteering opportunities email: lesley12@liv.ac.uk or rimd@liv.ac.uk
Text © Liverpool University
images © Laurie Campbell
