Dolphin Brain vs Human Brain: What Are the Differences?

Humans and dolphins are often compared to one another since it was discovered that dolphins possess a high level of intelligence. Dolphins are mammals capable of problem-solving and engaging in highly social behaviors. That has made many people, including scientists, wonder: what are the differences between a dolphin brain vs human brain?

These brains are very different in some ways but also similar in others. We’re going to show you how our brains are different from dolphin brains and the impact that these differences have upon each species. For the sake of our comparison, we will be using the brain of a bottlenose dolphin as a contrast to the average human brain. That particular species has been studied most thoroughly, so data about them is more widely available.

Comparing a Dolphin Brain and a Human Brain

The Key Differences Between Dolphin Brain vs Human Brain

The greatest differences between human brains and dolphin brains are their overall size, hippocampus, and cerebral cortex. Dolphin brains are larger than human brains, weighing 1,600 grams compared to the human brain that weighs 1,300 grams.

Human brains have a highly developed prefrontal cortex, the largest of any primate, but the dolphin’s prefrontal cortex is small and underdeveloped. Lastly, humans have a larger hippocampus area in the brain compared with dolphins.

These are the three greatest differences in the human brain and dolphin brain, and they can help explain the disparity in intelligence between the two species.  

Dolphin Brain vs Human Brain: Size

Dolphins’ brains are larger than humans’ brains. The average dolphin brain weighs about 1,600g and the average human brain weighs about 1,300 grams.

However, when we consider the size of a human brain vs a dolphin brain, it’s not enough to say that the bigger brain is the more intelligent creature. In fact, humans have a larger brain than dolphins relative to their body size. Even though dolphins have the largest brain-to-body weight ratio, they still fall behind humans in terms of intelligence.

Dolphin Brain vs Human Brain: Prefrontal Cortex Development

The human brain’s prefrontal cortex (PFC) is highly developed and the largest of any primate while the prefrontal cortex of a dolphin is limited in size. The PFC is the key to planning behaviors, making decisions, and engaging in social behaviors with others.

In human beings, the PFC is in charge of executive functions, allowing us to work towards specific goals and determine potential outcomes. The lacking PFC in a dolphin could help explain why they’re not as outwardly intelligent as human beings.

Dolphin Brain vs Human Brain: Hippocampus

The human brain has a far more developed hippocampus than the dolphin brain. The hippocampus is a somewhat small region in the human brain that is shaped like a seahorse. The hippocampus is responsible for the elements of memory, learning, motivation, emotion, and more.

In the human brain, the hippocampus is most often considered in terms of how it impacts memory. Having a better-developed hippocampus allows humans to have better long-term memory than dolphins. This might explain another reason that humans are capable of more complex cognitive tasks than dolphins. We can learn and retain information and then recall it later.

Dolphin Brain vs Human Brain: Cerebral Cortex

A dolphin brain has a greater level of encephalization in the cerebral cortex than a human brain. Dolphin brains have 40% more cerebral cortex than human beings. In particular, dolphin brains have more folds and ridges (gyri and sulci) in their cerebral cortex than humans.

Humans still have a highly developed cerebral cortex, though. However, our brains are not just smaller in terms of mass, but they have less overall surface area than a dolphin’s brain. Thus, we have not truly plumbed the depths of their intellectual capabilities.

The cerebral cortex is used to control higher-level thinking, motor functions, and other forms of information processing.

Dolphin Brain vs Human Brain: Encephalization Quotient

Human brains have a higher encephalization quotient than dolphin brains. The encephalization quotient is the ratio between the real and predicted brain mass of an animal-based on its body size.  

For human beings, the encephalization quotient is higher than any other animal at 6.56. Dolphins are not too far behind at 4.0 EQ.

However, some studies suggest that the EQ might not be the best way to measure cognitive abilities across non-human primates, meaning that measure might not be as significant as earlier studies have indicated. That is not to say that it’s not an important or insightful form of measurement.  

Why Aren’t Dolphins as Smart as Humans?

We’ve mentioned that dolphins have a larger brain than humans and they also possess greater encephalization in the cerebral cortex. So, why aren’t dolphins as smart as humans? Many reasons exist for this intellectual disparity.

For one thing, dolphins have a relatively small prefrontal cortex and even a small hippocampus. That means dolphins’ brains are limited in some rather significant ways. They don’t have the higher-level thinking, memory, the ability to set goals, and many other brain processes as human beings.

All in all, dolphins have incredible brains that we have only just now started to understand. Much of their brain processes remain a mystery to human beings. Although many differences between human brains and dolphin brains exist, the truth is that they are quite possibly the second-smartest creatures on Earth.

While that is very useful information and allows humans to learn about how brains and cognition work, it raises some ethical questions about keeping these animals in enclosures so they can be exhibited. Moreover, it raises further questions about what it means to kill a creature with this level of cognition. These disputes are important to consider now and require greater thought in the future.