Two ring-tailed lemurs, perhaps a pair, perhaps just two guys out to catch a few rays, sit side by side tilted back as if in beach chairs, their white bellies exposed, knees apart, feet splayed to catch every last drop of the Madagascar sun. All they need are cigars to complete the picture.
There’s a perfectly good evolutionary explanation for this posture. Scientists use the term “behavioral thermoregulation” to describe how an animal maintains a core body temperature. But as the animal behaviorist Jonathan Balcombe points out in his exuberant look at animal pleasure, “The Exultant Ark,” they are also clearly enjoying themselves. A scientist through and through, Dr. Balcombe can’t help giving the study of animal pleasure a properly scientific name: hedonic ethology.
Dr. Balcombe offers three primary arguments in support of the case that animals feel pleasure. First, pleasure is adaptive: Just as “pain discourages animals doing things that risk harm or death, which are not good outcomes in the evolutionary stakes,” he writes, pleasure “is nature’s way of improving survival and reproductive output.” ...
