Comment by delichon

  Perhaps not surprising, working breeds – many of which are known to have been artificially selected for high toy or predatory motivation – were overrepresented in the sample.

This is the vibe I get from my golden retriever. Chasing the tennis ball is more than play, it's a justification for life, her contribution to the pack. Actually eating food has a higher priority than chasing the ball, but not much else does. When I got her I thought that the "retriever" part was optional but it turns out to be obligate. As in I'm obligated to throw the damn ball.