Next to intelligence, another claim to fame that whales and dolphins can make is that of possessing culture. After the authors have clarified that they, too, wish to stay far from unsupported claims of higher intelligences and pseudoscientific attempts at cross-species communication, the book kicks off with definitions. Because, as with Justin Gregg’s book on dolphin intelligence, the proverbial devil is in the definition.

So what is culture? Whitehead & Rendell settle for the broad definition of culture being information or behaviour that is acquired from conspecifics through some form of social learning and which is shared within a community. Social learning, in turn, is learning influenced by observation of, or interaction with, another animal or its products, and community is a collection of individuals that is behaviourally self-contained and within which most individuals interact. This has bristled the hairs of scholars of human culture who dismiss such a definition as too inclusive, but, argue Whitehead & Rendell, it is a useful one, as it can shed light on the evolution and spread of culture in humans. Once you have culture, everything changes: new ideas are developed, superseding old ones, things are produced (technology, art, political systems) leading to complex societies. And, like it or not, it is what has made humans have an overbearing influence on the planet, subjugating it in the process some would say.

The thesis of this book is that whales and dolphins show a plethora of behaviours that spread through populations through social learning, that knowledge is passed on from generation to generation, and that evens fads and other short-lived phenomena can be observed. With a dispassionate and factual approach Whitehead & Rendell make their case.

First off, the ocean forms a habitat where having culture is potentially really useful. By its very nature, it is a world that is highly variable and three-dimensional. This has effects all the way up the food chain, making resources concentrated in local patches, rather than evenly distributed, encouraging cooperation. Since the ocean is so vast, it’s hard for one animal to make sense of it, and the accumulated knowledge of conspecifics can be a great resource.

Second, when cetaceans returned to the sea in their evolutionary history, brought some unique adaptations with them: breathing air allowed them to become large and fast-moving in oxygen-scarce waters. Air passages are well suited to producing loud and complex sounds, and the sense of hearing they inherited from their mammal ancestors exploits this. They arrived in the ocean with large and complex brains that grew even larger. And whale mothers care intensively for a small number of offspring, which is an excellent vehicle for social learning.

After setting the stage, the evidence is laid out, most of it from observations in the wild. Culture, so claim the authors, can be seen in the songs of baleen whales, which are fixed but change over timescales shorter than population turnover can account for, suggesting a role for social learning. In the diversity of dolphin foraging strategies around the globe, such as sponge carrying by Australian dolphins, and dolphin-human fishing cooperatives in Brazil and Burma. In the orcas, which show variation between different groups in vocalisations and foraging tactics. And in the vocalisations of sperm whales which similarly differ between groups. Finally, experiments on captive dolphins show that they are very adept at imitating both humans and each other, including learning to imitate sounds. There is also limited evidence of orcas and spotted dolphins teaching.

“We have a responsibility to err on the side of caution. Because, if anything emerges from this book, it is how much this field is still in its infancy.”

Whitehead & Rendell give ample room to their critics in the last part of their book, as their ideas are not free from controversy. Although the observations are undisputed, many scholars question if this is sufficient evidence of culture. The critics have two major bones of contention.

First, none of the cetacean behaviour observed in the wild has been experimentally demonstrated to rely on cultural transmission and could have an ecological or genetic component to it. Whitehead & Rendell are at the cutting edge of thinking about data analysis though, something which many biologists struggle with. Following traditional dichotomous hypothesis testing means you would have to rule out genetic and ecological influences, which is hard to do definitively. They argue a more Bayesian approach is required, trying to understand the relative contributions of each factor. Based on this they divide the above evidence in things that are definitely, likely and plausibly culture.

Second, the anthropological wing of the animal culture debate is critical of the whole idea of nonhuman culture, believing Whitehead & Rendell’s definition to be too simplistic and so too broadly applicable. They disagree and are comfortable with this broader definition, as it allows us to ask questions about what is going on in cetaceans, how it compares with other species, and how culture has evolved in different ways in different species. And it allows us to make the right decisions on how to coexist with whales and dolphins. I see no fault with their reasoning, and the observations that have been made are fascinating.

The book ends with a few further musings on the implications of accepting cetacean culture, such as whether a notion of culture should affect conservation efforts. Whitehead & Rendell make the case that, yes, it should. Indiscriminately catching whales can remove individuals from the population that are repositories of knowledge. And although culture can allow cetaceans to rapidly adapt to a new threat posed by humans, cultural species can experience a cultural bottleneck if reduced to low numbers.

We have a responsibility to err on the side of caution. Because, if anything emerges from this book, it is how much this field is still in its infancy. Observing whales and dolphins is incredibly laborious and time-consuming, and their habitat requirements pretty much preclude experimental work. Our knowledge so far is gleaned from a small number of species, while for the remaining 84 species of whales and dolphins we know next to nothing.

This book is a commendable effort to support the idea of whales and dolphins having cultural lives. The reading is at times be fairly dense, and certainly a few notches above pop-science reading, but in my opinion the book is accessible for a wide audience. And though Whitehead & Rendell feel passionately about their ideas, they clearly separate the facts from their interpretation of it, lending an ear to their critics. If cetaceans or animal behaviour are your thing, this is a must-read.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.