Ecology and behaviour: Mating

Behavioural observations

A close up of two foxes one on a wall and the other sniffing it
A pair of foxes; © Everything is permuted

For a long time, foxes were generally thought to be monogamous - a male pairs with a female fox and the pair stay together for life. There are many reasons why researchers came to this conclusion.

First, by observing foxes it was seen that the area over which a male fox roams, and which he defends against other foxes (his territory), largely overlaps the area occupied by the female. During the mating season, the pair are often seen together because the male follows the female closely. Also, once the female has given birth to the cubs, she spends the majority of her time in the den nursing them. During this period the male can be observed making frequent trips to and from the den to provision his mate. He then does the same to provision the cubs once they start eating solid food at about four weeks of age.

Other evidence, however, suggests that fox mating behaviour is not so straight forward. For example, during the mating season, female foxes are sometimes seen surrounded by several male foxes. Also, some studies have shown that, during the mating period, male foxes leave their home territories - and therefore their mate - and wander in search of other females. Also, in both Europe and North America, communal dens have been recorded where two or more litters of cubs are raised together.

The genetic study in Bristol

A DNA strand superimposed on the image of a graph

Recent genetic studies have helped unravel the mating system of foxes. Half of the DNA in an individual comes from his father, the other half from his mother. So, by examining DNA, it is possible to ascertain an individual's parents. Examining the DNA of cubs and adult members of urban fox social groups in Bristol, UK, revealed quite a complex picture. Dominant males mated with their own female but also with females from their own and other fox groups. Subordinate males (males further down the group hierarchy) did not mate with the dominant female in their group but mated with females from other groups. Bristol foxes were definitely not monogamous!

What happened after mange hit the population

The study described above was carried out between 1990 and 1994 when fox density in Bristol was one of the highest recorded for any fox population. In 1994, however, sarcoptic mange reached Bristol and the vast majority of foxes were infected and died. A second genetic study was then undertaken to find out whether the mating behaviour of foxes was different because fox density was so much lower.

This study showed that, at lower density, foxes were less promiscuous: dominant males mated with the dominant female in their own social group and with females from neighbouring groups, but to a lesser extent than at higher fox density. Subordinate males (males further down the group hierarchy) were not present. So, with fewer foxes and hence less competition, male foxes were less promiscuous but still not monogamous.

Question & Answer

TopAre foxes monogamous?

Foxes have a complex mating system. In some areas they are monogamous (one male paired with one female). In other areas they are polygynous (one male paired with two or more females). One study has also found promiscuous foxes. In short, foxes may or may not be monogamous.

 

References

  • Baker, P.J., Funk, S.M., Bruford, M.W. & Harris, S. (2004) Polygynandry in a red fox population: implications for the evolution of group living in canids? Behavioral Ecology 15, 766-778.
  • Lloyd, H.G. (1980) The red fox. Batsford, London.