Behavior and Neurology of Lizards 
N. Greenberg and P. D. MacLean, eds. 
NIMH, 1978. 
Ethological Considerations in the Experimental Study of 
Lizard Behavior 
Neil Greenberg* 
Laboratory of Brain Evolution and Behavior 
National Institute of Mental Health 
SUMMARY. The importance of an ethological approach to the experimental study of an un- 
familiar species is described and several of its problems discussed. The selection of units of be- 
havior is a crucial first step in the development of a behavior inventory. The correlation of a 
behavioral unit with a particular context is necessary to ascribe function to that unit and to de- 
velop an ethogram. Methods of studying lizards under controlled conditions are described and 
discussed. Constraints on behavior that must be considered in an experimental study include the 
microclimate and its thermal qualities, food and water, shdter utilization, and social behavior. 
Ritualized display patterns are proposed as sources of hypotheses about the neurophysiological 
control of social communications. 
INTRODUCTION 
This report -will first discuss some issues 
in an ethological approach to the study of an 
unfamiliar species and Avill then describe 
some observations that bear on the develop- 
ment of an experimental design for the study 
of lizard behavior in the laboratory. 
The observations described, both my own 
and those gleaned from the literature, are 
presented to indicate the complexity of the 
environmental constraints on lizard behavior. 
They constitute something of a guide for re- 
searchers — be they students of reptiles de- 
voted to a favorite group or those who see 
lizards as a possible model for experimentally 
testing hypotheses about the causation and 
function of behavior. 
THE ETHOGRAM AND UNITS 
OF BEHAVIOR 
Naturalistic observation is the essence of 
ethology and the fountainhead of hypotheses 
about the causation and function of behavior 
as well as the foundation on which experi- 
mental tests of these hypotheses must be 
built. 
*Present address: Department of Zoology, Univer- 
sity of Tennessee, Knoxville, TN 37916. 
The importance of the ethogram in the 
interpretation of an experimental study of 
a species is stressed by most ethologists (e.g., 
Lorenz, 1935, trans. 1970:111; Tinbergen, 
1951; Thorpe, 1973). Failure to consider all 
aspects of normal behavior has diminished 
the usefulness of many experimental studies 
(Adams, 1973; Eibl-Eibesfeldt, 1970; 
Thorpe, 1973). 
Units of Behavior 
A problem in developing ethograms has 
proven to be the objective delineation of 
separate units in what is a continuum of 
behavioral patterns. To minimize the arbi- 
trary nature of behavioral classification, the 
investigator attempts to identify reliable, 
easily recognizable diagnostic features. 
Ideally, behavioral units should be of the 
type that a neurophysiologist could deal with. 
Barlow (1968) asserts that, in this regard, 
only quantifiable behavior is of interest be- 
cause the behavior must be mathematically 
modeled if it is to be considered in neuro- 
physiological terms. But preoccupation with 
quantification can be hazardous, interfering 
with the Gestalt perception of a phenomenon 
203 
