as defined by dictionary.com is:
"performance by an animal of an act inappropriate for the stimulus or stimuli that evoked it."
or to put it in human terms:
performance of an act: updating my blog
the evoking stimulus: the looming deadline for completing my tax return
appropriateness: i'll let you be the judge of that, i'm off to panic over my tax return!
you can read a very good post about the above on sanctuary's blog