Table 2.

Behavioral indicators of arousal.

Behavior	Description
Hiding	Entire body concealed in the hidebox. Animal’s head and up to an additional head’s length of neck may be visible. Mutually exclusive with Exposed. State.
Exposed	Body is visible outside of the shelter. Mutually exclusive with Hiding. State.
Locomotion	Active movement of any part of body (except for tongue, see below). State.
Tongue Flick	Each discrete instance of tongue exiting mouth and re-entering mouth. Event.
Head out of sight	Snake’s head is not visible, such that the front of its mouth is unseen. State.