Rb. Lanctot et Lb. Best, Comparison of methods for determining dominance rank in male and female prairie voles (Microtus ochrogaster), J MAMMAL, 81(3), 2000, pp. 734-745
Dominance ranks in male and female prairie voles (Microtus ochrogaster) wer
e determined from 6 measurements that mimicked environmental situations tha
t might be encountered by prairie voles in communal groups, including agoni
stic interactions resulting from competition for food and water and encount
ers in bur-rows. Male and female groups of 6 individuals each were tested a
gainst one another in pairwise encounters (i.e., dyads) for 5 of the measur
ements and together as a group in a 6th measurement. Two types of response
variables, aggressive behaviors and possession time of a limiting resource,
were collected during trials, and those data were used to determine cardin
al ranks and principal component ranks for all animals within each group. C
ardinal ranks and principal component ranks seldom yielded similar rankings
for each animal across measurements. However, dominance measurements that
were conducted in similar environmental contexts, regardless of the respons
e variable recorded, ranked animals similarly. Our results suggest that ind
ividual dominance measurements assessed situation- or resource-specific res
ponses. Our study demonstrates problems inherent in determining dominance r
ankings of individuals within groups, including choosing measurements, resp
onse variables, and statistical techniques. Researchers should avoid using
a single measurement to represent social dominance until they have first de
monstrated that a dominance relationship between 2 individuals has been lea
rned (i.e., subsequent interactions show a reduced response rather than an
escalation), that this relationship is relatively constant through time, an
d that the relationship is not context dependent. Such assessments of domin
ance status between all dyads then can be used to generate dominance rankin
gs within social groups.