July 21, 2011

Urban Fox Mothers Are The Decision Makers

New research has found that in urban fox families, the mothers are the ones who decide which cubs stay and which must leave.

Red foxes have successfully established themselves in urban areas, living in family groups with a dominant male-female pair and a varying number of subordinate adults, according to the researchers.

Some of the cubs remain in the family group for the rest of their lives, while others leave to search for another family to join.

Scientists have hypothesized what drives these individuals to leave the safety of their family.

Researchers have been studying the urban foxes in Bristol since 1977, giving a rare glimpse into their normally secretive lives.  The Bristol University's School of Biological Sciences spends nights following radio-collared foxes.

The researchers have successfully created extensive fox family histories through field observation with DNA paternity testing in labs.  They found that the cub's genetic relationships with female family members determine its dispersal strategy.

According to the findings, male cubs with dominant mothers disperse to avoid inbreeding while their sisters remain to enjoy the benefits of living with their dominant mother.  The opposite pattern is found for cubs born to subordinate mothers.

The researchers said the comparison of the dispersal strategies of cubs fathered by dominant males with those fathered by males outside of the family demonstrates that fathers appear to play no role in this decision.

Helen Whiteside, lead author of the study said in a statement: "There is a limited cost to the dominant male fox in allowing unrelated males to stay in the family group. Moreover, sneaky matings outside the family mean that dispersal is not a reliable mechanism for preventing inbreeding between fathers and daughters."

According to the researchers, control of cub dispersal is much more important for mothers than fathers.

"These findings have important implication for the evolution of dispersal and group living in social mammals, and provide a unique opportunity to advance our understanding of the key biological process of dispersal."

The team's paper was published in the journal PLoS One.


On the Net: