Behavior and Neurology of Lizards 
N. Greenberg and P. D. MacLean, eds. 
NIMH. 1978. 
Behavioral Differences Between Reptiles and Mammals: 
An Analysis of Activity and Mental Capabilities 
Philip J. Regal 
Museum of Natural History 
University of Minnesota 
SUMMARY. In the following discussion I have attempted to develop an ecological and evolu- 
tionary perspective in which behavioral capacities of reptiles can be isolated from one another 
and analyzed as adaptive tactics and strategies. I will discuss new information in cellular and 
cardiovascular physiology, as well as in behavioral and population ecology. My goal is to provide 
an appreciation for the difficulties and rewards one may encounter as he tries to understand the 
occupation of different adaptive zones by reptilesand hence the adaptive functions of their nerv- 
ous systems. 
ACTIVITY IN REPTILES 
Foraging 
Descriptive accounts of reptile activity 
rarely reveal the foraging strategy, or se- 
quence of behaviors leading to an encounter 
with prey. The following accounts of forag- 
ing strategies are based on my own observa- 
tions on the reptiles of the New World 
tropics and North American deserts, on 
discussions with colleagues, and on the frag- 
mentary literature. 
I wish to identify, for discussion, points 
within a spectrum and not to imply categories 
with boundaries. 
Sit-and-wait Predators occupy a perch 
while active. Here diurnal reptiles bask 
and watch for prey to emerge or wander by, 
only occasionally rushing out to catch a 
passing insect, drive off an intruder, mate, 
or change position. Some sit-and-wait preda- 
tors change perches occasionally, others 
frequently. 
Cruising Foragers may move about their 
home range slowly, alert and responsive to 
prey but not obviously “searching for” prey. 
Such reptiles are more likely to find hetero- 
geneously distributed prey species. 
Intensive Foragers are characterized by 
the rapidity with which they move about over 
a relatively large home range, but they also 
appear to visually scan the environment with 
frequent jerks of the head and examine the 
substrate with frequent tongue flicks. Dig- 
ging and poking the snout into holes and 
under litter are also frequent. Intensive 
foragers may spend much energy in hunting 
for food and thereby gain access to concealed 
and/or heterogeneously distributed food re- 
sources unavailable to the sit-and-wait preda- 
tor or even the cruising forager (Schoener, 
1971). 
The Iguanidae, Agamidae, Chameleonidae 
and Gekkonidae — members of Camp’s (1923) 
Ascalabota — provide some of the best ex- 
amples of the sit-and-wait predatory 
strategy. As described by Cogger (1967) 
the agamid {Amphibolurus inermis) is 
usually seen on its perch, even in the very 
hottest part of a summer’s day, from which 
it makes forays to catch passing insects 
(also Heatwole, 1970). Similar observations 
are seen in the iguanids Uta (Tinkle, 1967) 
and Crotophytus (Fitch, 1956). Similarly the 
geckos I have seen are quite active if insects 
are abundant; otherwise they sit-and-wait 
for prey. At least some of the gecko-related 
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