The idea that humans alone have the capacity for intelligence, self-awareness, and emotions has a long history. Early in the scientific revolution, René Descartes helped establish the perception of animals as stimulus-response machines, driven purely by instinct and lacking any capacity for reason. Generations of scientists have subsequently been influenced by this viewpoint, with only the occasional dissenter.

One of the contrarians was none other than Charles Darwin, who recognized the emotional similarities between humans and animals, noting that “the difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind.” In 1872, he wrote an entire book on the subject (The Expression of the Emotions in Man and Animals). But despite Darwin’s scientific prominence, he failed to dislodge the prevailing viewpoint that emotions are the exclusive domain of humans.

In his latest book, Mama’s Last Hug, primatologist Frans de Waal joins Darwin and others in documenting the emotional continuity between animals and humans. Having studied primates for the past 50 years, de Waal is an authority on the topic of animal behavior. His research is published in top academic journals and he has written several popular books, including Chimpanzee Politics. In Mama’s Last Hug, de Waal constructs a compelling case for the rich intellectual and emotional lives of animals. In doing so, he refutes the simplistic Cartesian view of animals.

Mama’s Last Hug is loosely structured around de Waal’s experiences with Mama, a charismatic chimpanzee that lived in the Burgers’ Zoo in the Netherlands. Mama was a remarkable ape that wielded tremendous social influence within her colony. Weak and crippled from arthritis, she died just prior to turning 59 years old, but not before sharing an emotional reunion with a researcher she knew for 40 years. Mama’s tender expressions during this final embrace are a remarkable anecdote, one that serves as a springboard for de Waal to regale us with other fascinating tales of animal behavior. But his book is filled with more than just anecdotes. He also offers insights gained from experiments and observational studies of captive and wild animals (an extensive bibliography is provided). Topics include empathy, guilt, laughter, and free will.

It does not escape de Waal that many scientists find it difficult to accept emotional behavior in animals, and he tackles this issue directly. There are probably few among us who were not warned during our scientific training of the dangers of anthropomorphizing. To assign human attributes, especially emotions, to other animals was perceived as a grievous scientific faux pas. But denying commonality between humans and animals results from a culture of human exceptionalism, de Waal writes, adding, “I, myself, consider the rejection of similarity between humans and other animals to be a greater problem than the assumption of it. I have dubbed this rejection anthropodenial.”

It is reasonable to assume that there are similarities between the minds of humans and those of other animals because evolution has shaped the brains and minds of both, de Waal contends. In other words, evolution does not stop at the neck. If nonhuman animals possess brain anatomy that is fundamentally like that of humans, why would we expect their brains to function radically differently? Voltaire once said, “Has nature arranged all the means of feeling in this animal, so that it may not feel?”

Does de Waal argue that animals have human emotions? Not necessarily. While chimpanzees and humans might both demonstrate joy or envy, for example, that does not imply that their minds experience these feelings in the same way. To help us understand this, de Waal explains the differences between emotions and feelings: emotions are displays that can be observed and measured, whereas feelings are internal states and immeasurable (at least currently).

Mama’s Last Hug is easy reading due to its lack of jargon and esoteric scientific precepts. This explains why de Waal’s books are so widely popular. My main critique is that de Waal can sometimes take readers on a tangent without any clear direction. But he is careful to offer concise and poignant summaries at the end of each chapter.

Those interested in animal behavior will benefit from reading Mama’s Last Hug. It reflects the emerging realization that animals are not mindless automata, but instead can be intelligent, social, and emotional beings. It appears that such traits of the mind were adaptations that evolved long ago, and humans are just one of many species endowed with such gifts.

Matthew R. Fisher
Biology Faculty
Oregon Coast Community College
Newport, OR 97366