Predation is a powerful selection force which has lead to evolution of bewildering array of defensive structures and behaviors in various animal groups. Take for instance the body armor in sticklebacks, spine helmets in Daphnia, or fearful ‘lets-not-move’ type of behavior in many species, populations and life stages subject high risk of predation.
According to a report in the last week’s Helsingin Sanomat (HS 3.3.2009 kaapo.pdf), a jackrussel terrier Kaapo from Kuopio appears to know something about predation. In a late evening walk on the ice of a lake, he became a subject to attacks of an eagle-owl (Bubo bubo). The owl grabbed Kaapo twice, but due to his cunning synthetic armor, Kaapo escaped both predation attempts and managed to hide in reeds.
Happily and physically intact, Kaapo appears to express also adaptive phenotypic plasticity: he refuses to go out and does his things indoors. Rational behavior I would say: I guess that the risk being killed by your owner for indoor pooping is smaller as compared to what might happen outdoors.