Log^Q Average Number of Lines Crossed in 5 Minutes 
Reptile Activity 
185 
FIGURE 1 
Figure 1. Rates of spontaneous activity in three lizard species and a mammal. Leiocephalus schreibersi 
(Iguanidae) is a sit-and-wait predator. The behavior in nature of the secretive Klauberina riversiana 
(Xantusidae) is poorly known. Ameiva chrysolaema (Teiidae) is possibly typical of the intensive forager 
teiids. Here in a laboratory open-field test, the rates at which Ameiva crosses lines are comparable to those 
for a “gerbil” (Meriones unguiculatus) . 
After 15 minutes in the open field, the number of lines crossed was recorded for the next 15 minutes. Each 
individual was studied once in the morning and once in the afternoon, and these data were pooled and 
reported as a 5-minute average. n=6(L.s.), 8(K.r.), 9(A.c.), 2(M.u.). 
nrrthe number of individuals in each sample. The range and one standard error are indicated on each side 
of the mean. Analysis of variance procedures showed a highly significant species effect (F=39.5, Degrees 
of Freedom 2, 20, p <<.001). Further, multiple comparisons based on the F-statistic showed that means 
for all lizard species were significantly different at the 0.1 percent level. Statistics were performed for log- 
transformed data. 
may be engaged in the energetic function of 
basking. Often, basking lizards appear alert 
and responsive to moderate stimuli. And, at 
other times, they are somewhat refractory to 
visual, auditory, or tactile stimuli (Green- 
berg, 1973). The immobility of some lizards 
may also result from their sit-and-wait 
strategy of predation. So for this reason, too, 
their level of arousal may not be clear from 
simple behavioral observations. 
Electroencephalography 
The literature shows that the arousal 
spectrum of the brains of reptiles may not 
be described by any simple set of criteria. 
Information is available on 14 species of 
reptiles (Table 1). The interpretation of 
EEGs is confusing because it is difficult to 
know if a reptile is “sleeping.” In only a few 
of the studies has any attempt been made to 
correlate EEGs with changes in arousal 
thresholds. 
“Behavioral arousal” may be accompanied 
by an increase in the amplitude of the EEG. 
I have observed it in Tupinambis. Hunsaker 
and Lansing (1962) reported a decrease in 
amplitude in Sceloporus. 
