This book explores two questions:

  1. What kind of beings are dolphins? That is, what does scientific research reveal about their cognitive and affective abilities, and what are the philosophical implications of these findings?
  2. In light of the kind of beings they are, is the current state of human/dolphin interaction ethically acceptable? This book argues that dolphins have intellectual and emotional abilities sophisticated enough to grant them “moral standing”; they should be regarded at least as “nonhuman persons”; and the current state of human/dolphin interaction (characterized by the deaths and injuries of dolphins in connection with the human fishing industry and the use of captive dolphins by the entertainment industry for therapeutic purposes and by the military) is ethically indefensible. Accordingly, this book lays the foundation for the claim that the current relationship between humans and dolphins is, in effect, equivalent to the relationship between whites and Black slaves two centuries ago.


Dolphins: consciousness, intelligence, personhood and moral standing

Dolphins possess the sophisticated cognitive and emotional abilities characteristic of the type of consciousness that is the foundation of humans’ claim for moral standing. If individual humans are entitled to special consideration, then so are individual dolphins.

Dolphins possess the “biological hardware” to support such abilities. Like the human brain, the dolphin brain has a large cerebral cortex and a substantial amount of associational neocortex. Most anatomical ratios that assess cognitive capacity (brain weight/spinal cord, encephalization quotient) place the dolphin brain second only to the human brain. However, the fact that dolphins have a different and longer evolutionary history than humans has probably produced important differences in how the brains of these two mammals operate. For example, limbic or emotional information may play a larger role in the dolphin brain than it does in the human brain. And the human brain may emphasize detail, while the dolphin brain may emphasize speed.

Scientific research into the “inner world” of dolphins reveals signs of an advanced consciousness that have traditionally been thought to be unique to humans: selfawareness; emotions; self-conscious reflection on the contents of consciousness; solving problems by using abstract thought; grasping the causal structure of one’s environment; innovative and creative thinking; operating in “foreign cognitive environments”; and using tools. Dolphins have also demonstrated the ability to work with the basic elements of human language: vocabulary; grammatical rules and grammatical categories that assemble symbols into meaningful sentences; sentences as complex as 5- word commands that include modifiers and both direct and indirect objects; and questions as well as commands.

Most evidence for dolphin intelligence, however, points to a high level of social intelligence. Dolphins cooperate with each other—even forming second-order alliances in some communities—in handling the most important tasks for survival. They keep aggression from getting out of hand. They appear to have both acoustic and nonacoustic ways to communicate vital information to members of their school. And they devote a good deal of time and energy to developing and maintaining strong relationships with other members of the group. Indeed, the centrality of relationships in their lives probably means that on a daily basis they process more emotional information and are called on to use emotional skills more than humans do. It is difficult to look at all of this and not conclude that there is an impressive level of intelligence behind it.

Dolphins, then, clearly qualify as “nonhuman persons” with a moral standing equivalent to humans. “Persons” are traditionally regarded as beings who: are alive and aware of their environment; have the capacity for pleasure and pain; have emotions and a sense of self; control their actions; recognize other persons and treat them appropriately; and have a variety of higher order intellectual skills (including abilities to learn, to communicate, to solve complex problems, and to engage in abstract thought). Scientific research on dolphins shows that they have all of these traits. That is, dolphins are unquestionably a “who,” not a “what.” They are persons, not objects or property.

However, a special challenge that our species faces in fashioning the basis of an interspecies ethic is to avoid anthropocentrism. Philosophers may use the concept of “personhood” to avoid species-bias, but the way that the concept gets defined still amounts to saying that other beings deserve special consideration only if they’re “just like us.” This is apparent, first, in the way that the issue of whether nonhumans have “language” takes a central place in discussions of cognitive abilities in nonhumans. Like “intelligence,” however, “language” is best understood as a species-specific trait related to the survival imperatives of the particular environment in which a specific species evolved. (In this regard, the claim that language is a function of the “co-evolution” of the human brain and the human hand is particularly important.) The second problem with the traditional definition of personhood is that it fails to recognize some of the key cognitive and affective differences between humans and dolphins that may arise from the fact that cetaceans evolved in the water, e.g., a fundamentally “social self” and the suppression of individuality in dolphins. All of this suggests fundamental differences in the inner worlds of our different species—a fact that is particularly relevant to the question of what counts as ethically acceptable treatment of dolphins.

Interspecies ethics

The two industries whose behavior currently puts dolphins at greatest risk are the fishing and entertainment industries.

  • Purse-sein fishing for tuna in the eastern tropical Pacific still kills and injures thousands of dolphins each year. Particularly since there are other (and possibly more profitable) ways to catch tuna, it’s hard to imagine how fishing “on dolphin” (and other fishing practices that harm dolphins, e. g, drift nets and the Japanese “drive hunts”) can be defended.
  • More than 1500 dolphins are used in captive entertainment facilities in different parts of the world. These dolphins typically live with a small number of other dolphins in small concrete tanks. Defenders of captivity cite benefits to humans and dolphins. Humans are entertained, and our curiosity about dolphins is satisfied through scientific research. Captive dolphins receive food and medical attention; even wild dolphins may benefit from the increased appreciation that humans may develop for dolphins after seeing them; captive and wild dolphins alike can benefit in various ways from what we learn through research; successful captive breeding programs have virtually ended the practice of capturing wild dolphins for use in entertainment facilities. However, even the best facilities are not ethically defensible. Dolphins do not consent to their situation, and the barren social conditions in which they live make it unlikely that their personalities can develop in a full and healthy fashion. The benefits do not outweigh the harms; the benefits flow mainly in one direction (to humans); and the dolphins involved are not being treated in a way consistent with their advanced traits and needs. Moreover, the idea of treating a species of selfaware beings with a sophisticated consciousness as “property” not “persons,” and breeding them with an eye toward the traits that will make them most useful commercially has chilling similarities with the practice of human slavery. Capturing, selling, buying and/or breeding is inconsistent with the dignity due any self-aware being.
  • The same critique can be made of dolphins being used for therapeutic or military purposes.

In view of the unacceptability of these practices, what do we do?

  • Humanity’s most pressing obligation is to find ways to discontinue fishing practices that harm individual dolphins.
  • Captive facilities should cease all of the current captive breeding programs. (Given the entertainment potential and cost effectiveness of video technologies like IMAX movies that portray dolphins in the wild, theme parks that begin integrating such technologies into their operation should be able to remain profitable.)
  • There is no perfect solution for the hundreds of dolphins who currently live in captivity. There is little likelihood that many (if any) could be trained to live in the wild. So, realistically, they should probably remain where they are for the rest of their lives. The current captive generations will then die out over the next 40 to 50 years.
  • In view of the predictable end of a pool of captive dolphins for research, new dolphin researchers should be steered by their mentors into research in the wild.