comparative approach, and to discuss not only the behav-
ior of their subjects but also that of ecologically similar and
phylogenetically related species. We instructed authors to
differentiate proximate (mechanistic) from ultimate (evolu-
tionary) causes of behavioral phenomena, and to emphasize
the usefulness of integrating results at different levels of
analysis. Finally, we encouraged authors to highlight the
roles of experimentation and hypothesis testing in advanc-
ing our understanding and in developing the next genera-
tion of predictive models.
All chapters were peer reviewed, sometimes by authors of
related chapters, in an attempt to enhance integration. The
resulting volume attests not only to the authors’ expertise,
good humor, and willingness to revise and reconsider their
work in light of constructive criticisms and new informa-
tion, but also why these contributors have made studying
rodent societies their life’s work. We hope that after diving
between the covers of this volume, you too will be struck by
rodentophilia!
We begin this anthology with a summary of the evolu-
tion, phylogeny, and biogeography of rodents, to provide
an historical context and a basis for comparative analyses.
We divided the subsequent 39 chapters into seven major ar-
eas that characterize rodent societies. These include sexual
behavior (chaps. 3 –7), life history (chaps. 8 –15), behav-
ioral development (chaps. 16 –19), social behavior (chaps.
20 –25), antipredator behavior (chaps. 26 –28), compara-
tive socioecology (chaps. 29 –37), and conservation and
disease (chaps. 38 – 41). Although each section focuses on
a particular aspect of rodent social biology, several central
themes reemerged throughout each chapter and the entire
volume, enabling us to identify some universal components
of rodent societies.
Universal Components of Rodent Societies
A basic understanding of behavior quickly reveals patterns
that recur in various taxa. And in that rodents have been
studied extensively in many areas of behavior, ecology, and
evolution, authors have been able to synthesize theory with
empirical studies to develop conceptual models to explain
many aspects of rodent societies. It is these predictable pat-
terns that we attempt to emphasize in this anthology.
Regarding reproductive strategies, we deviated from the
conventional approach of chapters on monogamy, polyg-
yny, and promiscuity, in favor of examining sex-specific
mating strategies. Thus there are chapters on male mating
strategies (Waterman, chap. 3) and female mating strategies
(Solomon and Keane, chap. 4), and these focus on indi-
vidual reproductive behaviors rather than the species- or
population-level mating system. Our authors demonstrate
how sex-specific mating and reproductive tactics maximize
fitness; similar tactics also occur among males and females
of other mammalian taxa. Carroll and Potts (chap. 5) use
house mice as models to demonstrate the importance of fe-
male choice in selecting for genetically compatible mating
partners. The ideas, mechanisms, and results are applicable
to sexual selection theory in that they provide evidence for
the “compatible genes” hypothesis for mate choice. In a
phylogenetic analysis of breeding systems in Neotomine
and Peromyscine rodents, Kalcounis-Rüppell and Ribble
(chap. 6) examine a series of behavioral and ecological pa-
rameters to develop a model that predicts mating systems.
Koprowski (chap. 7) also uses a comparative approach in
describing alternative sexual behaviors in male tree squir-
rels, which reveals how male tactics are dependent in part
on female tactics. All these authors remind readers of the
evolutionary arms race between the sexes, and their chap-
ters demonstrate how the behavioral strategy of one sex of-
ten is dependent on the behavior of the other sex. Mating
systems are thus a consequence of alternative mating tactics
used by males and females.
All animals must communicate with each other at some
time, especially during intrasexual conflict and for mating
and defensive purposes. Important aspects of communica-
tion that have been well studied in rodents include chemical
factors in urine that accelerate and suppress reproduction
(Drickamer, chap. 9), express dominance and territoriality
(Roberts, chap. 22), and serve as cues of genetic compati-
bility in mate choice (Carroll and Potts, chap. 5). Vocal
communication, especially alarm calling, has also been well
studied in rodents (Blumstein, chap. 27, and Hoogland,
chap. 37), as has nepotism (assisting kin) more generally
(e.g., Holmes and Mateo, chap. 19).
A major theme that unites this volume is the importance
of genetic relatedness in modulating the social behavior of
rodents, as showcased, for example, in the chapters on
general topics such as social learning (Galef, chap. 18), kin
recognition (Holmes and Mateo, chap. 19), parental care
(McGuire and Bemis, chap. 20), alarm calling (Blumstein,
chap. 27, and Hoogland, chap. 37) as well as in chapters fo-
cused on specific taxa, including beavers (Busher, chap. 24),
mole-rats (Nevo, chap. 25; Faulkes and Bennett, chap. 36),
ground squirrels (Hare and Murie, chap. 29), and marmots
(Armitage, chap. 30). Social groups of kin most often re-
sult from philopatry of daughters (Solomon and Keane,
chap. 4), which in turn creates advantages for males that
disperse to seek unrelated females for mating and to avoid
inbreeding or reproduction competition in the natal site
(Nunes, chap. 13). Coloniality, sociality, and especially eu-
sociality depend on kinship (Lacey and Sherman, chap. 21)4 Chapter One