Keeping silver fox in groups influences social behaviour

Janne Karin Brodin

When several silver fox cubs are kept in the same cage, it is clear that the placement of feed trays, platforms and boxes they can hide in influences their behaviour and the choices the animals make. The social status of the individual animal is also influential.

Anne Kathrine Akre Photo:

These are some of the conclusions PhD candidate Anne Kathrine Akre has drawn in her doctoral thesis.

Traditionally, adult farmed silver fox are kept in individual wire mesh cages with a resting and climbing platform, activity objects and a nest box or other furnishing where the animal can seek shelter.

Several animals together
Keeping animals in groups or in pairs is often suggested as an alternative way of increasing the animals’ possibility for species specific behaviour and also for stimulation to more movement and exploratory behaviour.

Group stalling can, however, lead to increased competition for the resources within the cage, such as feedstuffs, shelving and boxes, and it can lead to escalated aggression.

The starting point for this doctoral work was the need to investigate how factors such as familiarity with other individuals, age, social status and allocation of resources in the cage influence the choices the animal makes (their social preferences) and other social behaviour. Four different tests were carried out.

Play seems to be the motive for contact among the youngest pups
In the first test, the social preferences of young silver fox vixens were examined. The pups were put in cages separated by netting screens, and their behaviour was observed over a period of time.

The results showed that young silver fox pups sought out social contact with other pups, and that familiarity did not influence the time they spent in front of the other pups. The pups showed a tendency to play more in front of unfamiliar pups than in front of familiar ones. This may indicate that the motive for pups’ seeking contact was not so much related to aggression as to play.

At age six months, vixens showed no clear preference for a familiar or an unfamiliar vixen, but they displayed more aggressive behaviour towards the unfamiliar ones. This result shows that the vixens’ motivation for competitive behaviour is increased at this age.

The choice test apparatus (2.4 × 1.8 × 0.75 m) seen from a bird’s perspective. It comprised of a choice arena (2.4 × 0.8 m) and three stimulus compartments (0.8 × 1.0 m each) where the middle one was an empty compartment, with no stimulus animal. Cage measurements are given in m. ___ = solid walls, _ _ _ = wire mesh walls, ..……..= water stations. Photo: Akre

Social status counts
In the second test, young silver fox vixens’ social preferences were examined as related to the social status of the animals. The results indicate that low status vixens tend to avoid high status vixens. This form of avoidance of a particular social partner was not seen in high status vixens.

Placement of resources such as food and boxes is important

The effect of the distribution of resources on behaviour and competition in paired silver fox vixens was the theme of the third test.

The results showed that keeping vixens in an environment where resources – feeding tray and box – were placed closely together increased competitive behaviour. The vixens kept in this environment had a higher frequency of physical aggression at feeding time, and a lower body weight than vixens stalled in environments where the resources were distributed over a larger space. However, during the days after the vixens were paired, aggressive interactions among the vixens decreased and positive reactions increased as measured throughout the day.

Silverfox Photo: Anne Kathrine Akre

Mice as model animals
To shed more light on the effect of environmental factors on social behaviour among caged animals, mice were used as a model animal in the fourth experiment. The social system of mice is comparable to the one found in groups of foxes, hence mice were chosen as a model animal.

The results showed that familiarity with the cage partner had no effect on the behaviour of paired female mice. The results also showed that mice kept in the environment where resources were placed closely together displayed increased aggression, increased tendencies to drive each other away from the resources and increased stereotypic behaviour than mice kept in an environment where resources were distributed over a larger space.

Increases understanding of social behaviour
This doctoral work will contribute to an increased understanding of how animals’ social behaviour is affected by their physical and social environment. The experiments showed that, in order to avoid increased aggression, it is important to take familiarity, age and social status into account as well as the distribution of resources when housing animals together.

Anne Kathrine Akre is 29y ears old and form Fredrikstad municipal. He took his Master degree in ethology in 2005 at The Norwegian University of Science and Technology (NTNU).The trail lecture and public defence took place April 30th at IHA. Title of the thesis: The role of social and physical environments on behaviour in silver fox (Vulpes vulpes) vixens and female mice (C57/BL/6J). Prescribed subject of the trial lecture:How can lessons about social behaviour in wild animals be applied on domesticated animals?

Akre’s main supervisor has been Professor Morten Bakken. Assistant supervisors have been Post doc Anne Lene Hovland, IHA, Associated professor Inger Lise Andersen, IHA and Professor Georgia Mason, University of Guelph, Canada.

The project has been financed by The Norwegian Research Council

Updated: 04.05.10
Printerfriendly version

Del med en venn:

Department of Animal and Aquacultural Sciences

P.O. Box 5003
N-1432 Ås

Phone: +47 64 96 51 00
Fax: +47 64 96 51 01

E-mail: iha@umb.no

Webmaster: Janne Karin Brodin