Vigilance involves basic information gathering (Bekoff 1995). It is the active act of deliberate watchfulness and monitoring of potential threats caused by predators and even conspecifics. Heightened vigilance in animals is usually based on specific environmental circumstances, such as a noise or a movement that may warrant careful assessment. Heightened vigilance may also be indicated if an environment is unfamiliar and/or if visibility is poor and could potentially hide an ambush predator. Vigilance is associated more with prey species than with predators" at least the need for vigilance may be ongoing in prey species but be rare or intermittent among predators unless a competitor is nearby. In addition, vigilance is associated with the protection of nest sites (Yasukawa et al. 1992) and dens (Santema and Clutton-Brock 2013) (Figs. 1 and 2).