150 
Crews 
MALE 
FEMALE 
and its structural and social environments 
has become one of the major themes in be- 
havioral endocrinology today. 
LIZARDS AS EXPERIMENTAL ANIMALS 
IN PSYCHOBIOLOGICAL RESEARCH 
Much of my own research has been con- 
cerned with this interaction of behavior and 
hormones and how their interrelationship 
might influence another animal’s behavior 
and reproductive physiology. Although this 
interest was first stimulated by Lehrman’s 
work with the ring dove, it seemed to me 
that further insight into the generality and 
possible evolutionary and adaptive signifi- 
cance of principles arising from Lehrman’s 
and others’ psychobiological research would 
come from work with species other than the 
laboratory birds and mammals that are com- 
monly used. While inbred laboratory species 
are useful for certain physiological studies 
and for elucidating complex psychoneuro- 
endocrine relationships (e.g., the milk ejec- 
tion reflex in mammals), it is necessary to 
study feral animals in nature or in carefully 
controlled, simulated habitats to understand 
how these interrelationships adapt animals 
to their particular environments. 
Although present-day reptiles cannot be 
considered to be more primitive than extant 
birds or mammals, their common ancestry 
and similarities with the so-called “higher” 
vertebrates make reptiles an important ver- 
tebrate class with which to investigate the 
