A one-year study of gastro-intestinal parasitism in a free-ranging
population of maras at
Whipsnade Wild Animal Park,
UK, revealed a strong relationship between membership of social units and
both intensity and
prevalence of infection.
The mara, a hystricomorph rodent from southern Argentina, has a social
organization including both
monogamy and communal denning of the young, an apparently unique combination
among mammals. From
October 1992 to September 1993, strongyloid parasite loads were estimated
from faecal egg counts.
A minimum adequate model was fitted to the data
using the Genstat statistical package. This showed that family membership
had a highly
significant effect on the intensity
of egg shedding in faeces, and a significant effect on the prevalence of
infection. After
controlling for both extrinsic
environmental and intrinsic demographic factors, homogeneity of infection
was greater within than
between families and adult pairs.