Behavior of Varanus Komodoensis 
309 
Figure 5. Fecal pellet of large adult monitor 
(19W) placed on open sand of dry creek bed. 
Visual Communication 
Visual cues include color, pattern, position, 
and form. Colors and patterns of potential 
communicative importance include the vivid 
juvenile body pattern, bright eyelid yellow 
of adults, and the bright yellow tongue in 
specimens of all sizes. Generally, however, 
color cues are probably not as important in 
this species as they are in others of the genus. 
Form and posture also play a role in com- 
munication. Components of possible import- 
ance are: raising the roach (crest); tail 
position (e.g., held straight and stiff, as 
opposed to lashing it or bowing it to one 
side) ; head posture (at angle to ground, 
sometimes also turned to side) ; and 
Schragstellung (the positioning of the body 
so that the greatest surface area is shown, 
lateral body compression, hyoid expansion, 
mouth open, and body raised high on legs). 
The Schragstellung is associated with de- 
fensive tactics and part of the threat dis- 
play. It is common in several species of 
Varanus (Mertens, 1946; Murphy and Mit- 
chell, 1974; Honegger and Heusser, 1969). 
Preceding and during an attack, the head and 
anterior parts of the body are usually 
lowered. A lateral sigmoid curve in the neck 
is often associated with an impending attack, 
as in snakes. 
During a threat display, many Varanus 
species, including V. komodoensis, commonly 
lower the head and arch the back (Mertens, 
1946). Typically, the head is turned slightly 
to one side so that the dorsal surface is pre- 
sented to the offending object. The eyes peer 
out from beneath their protruding brow and 
a defensive or offensive attack is usually 
imminent. The arching of the back and tail 
is a conspicuous visual cue used particularly 
by smaller individuals when approaching 
other monitors, or by large individuals when 
approaching or being approached by humans. 
It is often accompanied by a stereotyped, 
slow, stiff -legged walk in which the body is 
slowly thrown from side to side in exagger- 
ated lateral undulations (Fig. 6). 
Often accompanying such movements, but 
sometimes independent of them, is a 
display in which the throat is visibly en- 
larged (Fig. 8). This is accomplished by an 
anterior, lateral, and posterior movement 
of the hyoid apparatus so that the bottom 
of the throat looks like a slightly inflated 
balloon. It has been described in many Va- 
ranus species (e.g., Mertens, 1946; Cowles, 
1930). It is often associated with lateral 
body compression. To make the body appear 
even larger, the roach is often raised along 
the vertebral line of the neck and anterior 
half of the body. 
The multiplicity of contexts in which the 
roach is raised, hyoid expanded, and head 
held at an angle suggest that these mani- 
festations represent a stress reaction. This 
reaction does not appear to communicate a 
specific message but, rather, represents a 
general state of being to which other cues 
may be added. Together the entire complex 
constitutes a specific display, (see Table 5 
and Fig. 7). 
Visual display in particular provides sev- 
eral examples of behavioral scaling (varia- 
