Recent scientific discoveries highlighting the intelligence of a dolphin brain have sparked the dolphin brain vs human brain debate.
To the disbelief of many, scientific research has proven that dolphins, like humans, have an advanced problem-solving capability.
These cetaceans are also highly social, exhibiting complex social behaviours, and are known for their strong bonds. Their social nature allows them to live in groups that have defined social hierarchies.
Within these social groups, they hunt, nurture their young ones, and play and protect each other from threats. There are about forty-two known dolphin species in the world. This article will base our comparison on the bottlenose dolphin species.
The bottlenose dolphin is the most extensively studied species with plenty of known facts, making it ideal for this contrast.
So, which one is supreme in the dolphin brain vs. the human brain?
Dolphin Brain Vs Human Brain
While the dolphin brain is more developed than that of many mammals, it is not nearly as powerful as that of humans. Though smaller, the human brain has a superior Encephalization Quotient of about 7 with a more developed prefrontal and cerebral cortex.
These developments in the human brain empower it to function better than any other organism regarding executive execution, decision making and general intelligence.
Differences Between Dolphin Brain And Human Brain
Even though the dolphin brain is somewhat comparable to the human brain, the two have some distinct features setting them apart. Some of the variations between the two brains include;
1. Size & weight
The dolphin brain weighs about 1,600 grams on average compared to the human brain, which weighs 1,300 grams and is also considerably larger than that of humans.
However, when considering relative brain size concerning body size, human beings have bigger brains than dolphins. The size of the dolphin brain may vary depending on the species.
2. Cerebral Cortex
The cerebral cortex is the brain’s outermost layer, consisting of a highly convoluted sheet of neural tissue covering the entire cerebrum.
This part of the brain is responsible for many complex cognitive processes that distinguish humans from other animals with well-developed brains.
The human brain has a more developed cerebral cortex than a dolphin. In humans, this section of the brain is well-developed to handle complex functions like reasoning, language and conscious thought.
On the other hand, the cerebral cortex in a dolphin’s brain is less developed, making it less suited to process complex functions like in humans.
Regarding size and structure, dolphins have a 40% bigger cerebral cortex than humans. Their brains also have more encephalization levels with more folds and ridges (gyri and sulci) in the cerebral cortex than human brains.
3. Prefrontal Cortex Development
The Prefrontal Cortex is a region within the cerebral cortex in front of the brain, behind the forehead. This brain region is crucial for planning, problem-solving, impulse control, and working memory tasks.
The human brain’s prefrontal cortex is the most advanced of all primates. A superior prefrontal cortex makes humans shine regarding executive control, decision making and emotional control.
In contrast, dolphins’ brains have a small, underdeveloped prefrontal context that significantly limits their intelligence.
4. Hippocampus Size
The hippocampus is a seahorse-shaped part of the brain responsible for memory and spatial navigation in humans and dolphins. While there are some similarities in the function and structure of the hippocampus in both species, there are also notable differences.
For instance, the human brain’s hippocampus is relatively more prominent and more developed than that of dolphins. A more developed hippocampus gives humans better long-term memory compared to dolphins.
This variation in the hippocampus also explains why humans can handle complex tasks requiring more cognitive capabilities.
5. Encephalization Quotient (EQ)
The Encephalization Quotient (EQ) is a measure that compares the actual brain size of an organism to the expected brain size of an animal of a given body size.
Humans have one of the highest Encephalization Quotients among all species, with an average EQ of around 7 to 7.5. Such a high EQ means the human brain is significantly larger relative to body size than most other animals.
In contrast, the EQ of bottlenose dolphins is estimated to be around 4 to 5, which is relatively high compared to other non-human animals. This indicates that dolphins have a larger brain relative to their body size than many other mammals.
6. Sensory Systems
Since humans have evolved to live on land, our brains are highly developed for visual and auditory processing. In contrast, dolphins have relatively small visual cortices compared to humans.
Their brains are specialized for echolocation, a sophisticated form of sonar that allows them to navigate and detect prey underwater.
Similarities Between Dolphin Brain and Human Brain
Despite the evolutionary divergence of humans and dolphins, there are commonalities in the organization and development of specific brain structures. Some similarities worth mentioning are;
1. Denser Region of Cells in the Thalamus
The thalamus is a part of the brain responsible for relaying sensory information to different areas of the cerebral cortex. There is a denser region of cells in the thalamus in human and dolphin brains. This suggests that the thalamus plays a significant role in sensory processing in both species.
2. Cortical Development
The development of the cortex in dolphins is parallel to that of the human brain, suggesting that the two brains have evolved similarly. Both species have developed a relatively large and complex cortex in their respective lineages.
What Makes Dolphins Mammals?
Although dolphins have ‘fish-like’ features and live in water, they are still considered cetaceans (marine mammals), not fish.
Scientific research indicates that dolphins and hippopotamuses share a common ancestry, although the two species underwent divergent evolution to become what they are now.
Fossil evidence discovered in Pakistan over 45 years ago confirms that dolphins evolved from land to sea mammals. According to scientists, this evolution was necessitated by rapid environmental changes that required them to adapt to the aquatic environment.
So, what features make dolphins mammals?
1. Presence of Mammary Glands
Like all mammals, female dolphins have mammary glands for lactating. Dolphins nourish their calves by feeding them milk produced by the mammary gland for two to four years after birth.
Calves can suckle their mother’s teats underwater by curving their tongues into straw shapes, forming a seal over the mothers’ nipples!
2. Dolphins Have Hair
Although dolphins are primarily hairless, calves are born with hair covering their rostrum. These vestigial hairs are evidence of their mammalian heritage. The rostrum hairs eventually fall off as the calves age, leaving behind hair follicles through their adulthood.
However, its distinctive attribute is that, unlike other mammals, dolphins don’t need their hair to keep warm. Instead, they have a layer of fat underneath their skins called blubber that keeps their organs warm. This is the same layer of fat present in other sea mammals like seals and sea lions.
3. They Give Birth to Offspring’s
Dolphins give birth to live offspring after a gestation period of twelve months rather than laying eggs. This is a hallmark of mammals. After giving birth, female dolphins care for and nurse their young for over two years.
Sexual maturity in dolphins is pegged on the animal’s size instead of age. On average, dolphins’ reproductive maturity occurs when a dolphin attains 85%-95% of the species’ adult body size. This usually takes between five to twelve years.
4. Dolphins are Warm-Blooded
Dolphins, like many other mammals, are warm-blooded. This means they can regulate their body temperatures internally through metabolism, allowing them to live in warm and cold environments.
5. Dolphins Breath Through Their Lungs
Unlike fish, dolphins breath through the lungs instead of the gills. Their dependence on the lungs for respiration is why they often travel to the water’s surface to breathe. Upon reaching the surface, dolphins exhale low water from their blowholes, allowing them to inhale fresh air.
Most people, however, subscribe to the popular misconception that the water blown from the blowholes originates from dolphin’s lungs!
It is important to note that dolphins only breathe through their blowholes. This clear separation between breathing and feeding channels allows them to feed underwater without drowning.
6. Dolphins Have Three Middle Ear Bones
Like other mammals, Dolphins have three middle ear bones (the malleus, incus, and stapes). These bones transmit sound vibrations from the eardrum to the inner ear. This is part of their advanced auditory system, essential for echolocation and communication.
Dolphins are some of the most intelligent mammals on earth but need to be more smart to win the dolphin brain vs human brain contest. Both species have undergone many evolutionary changes, impacting their brains’ functional and structural aspects.
And while the dolphin’s brain has evolved to become bigger than that of humans, it is relatively underdeveloped, limiting its cognitive abilities. This is why the human brain has proven to be more intelligent than any other mammal on earth.