"Zhuangzi was right. So was June Thunderstorm. Our minds are just a part of nature. We can understand the happiness of fishes—or ants, or inchworms—because what drives us to think and argue about such matters is, ultimately, exactly the same thing."
Perhaps, but also it might just be that what we call "play" in ourselves is actually also "an expenditure of energy...directed toward some goal, whether it be obtaining food, securing territory, achieving dominance, or maximizing reproductive success". It's a more comforting thought to accept "animal" play because that helps confirm our "free will" illusion.