General Issues in Behavioral Development
In an epigenetic approach to development, ontogeny is
viewed as a series of interactions between an organism and
its environment (Lehrman 1970; Johnston 1987). In ad-
dition to this epigenetic or interactionist view of develop-
ment, some researchers have viewed development as a series
of ontogenetic adaptations, with each stage functionally
complete for that period of development and contributing
to later stages (Williams 1966; Galef 1981b; Owings and
Loughry 1985; Alberts 1987). These two approaches to the
study of development should be considered complementary
rather than competitive, however, as their interpretations
focus on different levels of analysis (Tinbergen 1963; Sher-
man 1988). That is, proximately, what experiential factors
influence the development of traits, and ultimately, are the
behaviors exhibited at each stage of development adap-
tive for that stage? Note that we should not think of young
animals as small adults, but as organisms with age-specific
needs and adaptations. Indeed, young have very different
selective pressures than do adults, and thus what is func-
tional for one age group may not be for another.
I will first discuss some examples of social, hormonal,
and environmental influences on rodent behavioral devel-
opment (fig. 17.1), and next discuss in detail one behavioral
system — anti-predator strategies — that can be affected pro-
foundly by interactions with parents, heterospecifics, and
physical environments. The richness of the subject at hand
forces me to be selective in the topics I present here. More
in-depth treatment of social development in other con-
texts can be found throughout this volume, including terri-
toriality (Krebs et al., chap. 15), natal dispersal (Nunes,
chap. 13), the altricial-precocial continuum (Dobson and
Oli, chap. 8), timing of puberty (Drickamer, chap. 9), and
the specific roles of parenting styles on offspring develop-
ment (McGuire and Bemis, chap. 20).Prenatal environmental and social influences
on development
Development, of course, necessarily begins at conception,
and the uterine environment of developing fetuses influences
their later morphology, physiology, and behavior. Sensory
and perceptual development in rodents begins in utero. The
onset of sensory function across development is remark-
ably consistent in birds and mammals, with the perceptual
senses showing the following order of onset: tactile, vestib-
ular, chemical, auditory, and visual. In altricial rodents, the
latter two systems may not be functioning until after birth,
and all systems continue to develop and form cortical con-196 Chapter Seventeen
Figure 17.1 Relationships among social, physical, and ecological factors that can influence rodent
development in a context-dependent fashion. Each factor can also moderate reciprocally the effects of
the other factors on development, such as when the local microhabitat and current weather impact the
potential for social influences on behavioral development.