NOTES TO CHAPTER 4 15111 For example, DeVries et al. (1997) claimed that in their lab prairie voles devel-
oped partner preferences through cohabitation, regardless of the sex of each
vole. In one study the researchers placed same- sex voles in close proximity for
twenty- four hours and observed that the voles developed attachments to each
other similar to attachments observed in opposite- sex couplings. The researchers
identified these attachments as “social bonds” rather than pair bonds, since by
standard definition pair bonds must be heterosexual. They also reported that
the reproductively naïve females, when given a choice, preferred other females
to males. This preference disappears only among females who have reproduced
when a male stranger is introduced. To make sense of these findings, DeVries et
al. hypothesized that same- sex “social bonds” are important for group formation.
This research opens up the recognition of relational variation among voles, while
also affirming a heteronormative hierarchy in the context of evolutionary theory.