"For decades, animal behaviorists have argued that play -- like all instinctive behaviors -- must have some deeper reason behind it. Citing the theory of natural selection, they say that if play behavior was completely frivolous, it would be a waste of time and energy and would have been eradicated over time. Clearly, these researchers need to get out and have fun more often." -- Dr. H. Ellen Whiteley, How to Solve Cat Behavior Problems (p. 2, "Understanding Cat Behavior")