Dolphins are perhaps the most intelligent aquatic mammal on Earth. With their self-awareness and abilities to communicate, reason, express emotions, adapt, and perform altruistic acts, they have spread across every ocean and many freshwater rivers in the same way humans have populated every continent. The cognitive abilities of dolphins are exceptional. Below is a close examination of this mammal’s brain size, structure and remarkable cognitive abilities.
I. Brain Size/Structure:
Dolphins have a large, folded brain with an exceptional intellectual capacity. As a result, they learn extremely quickly and possess the ability to produce creative responses.
Although their cerebral cortex is 40% larger than that of humans, it is shallower, resulting in a neocortical volume that is 80% of that of humans. Nonetheless, both possess comparative cerebral hemispheres and folding to process sensory information and stimuli.
The average bottlenose dolphin brain weighs 1.7 kg (.4 kg more than the average human brain). When comparing brain size to body size – the Encephalization Quotient (EQ), the average dolphin brain registers between 4 and 5 (second to the 7 EQ of the average human brain and significantly higher than the EQ of any other type of animal including the great apes). This indicates a close proximity to human cognitive abilities.
In comparison to humans and other land mammals, a dolphin’s brain has five versus six layers in their neocortex, with no functional segregation. This likely permits humans to focus on greater detail and dolphins to process sensory information at greater speeds, which may be more critical in a 3-dimensional water-based environment with few distinguishable landmarks where sound travels 4-5 times faster than on land.
In addition, relative to brain size, a dolphin’s brain has a significantly larger cerebellum than a human. This is likely since an aquatic environment places greater need on motor control. Furthermore, a dolphin’s cerebellum is also larger due to the absence of functional specialization, since it is likely used for cognitive processing monstruos marinos reales.
Unlike the human brain, a dolphin’s brain includes a paralimbic lobe to enhance integrated information and emotional processing. It is likely that emotions play a greater role in a dolphin’s life than a human life.
Dolphins generally sleep in a semi-alert state by closing one eye and resting one side of the brain at a time. They usually alternate, closing one eye for 5-10 minutes and then the other. Within a 24-hour period, dolphins generally rest each eye and each side of the brain between 3-4 hours.
This is necessary so that dolphins can keep a lookout for potential predators – usually large sharks and killer whales. Remarkably, many dolphins in captivity, having recognized the absence of potential predators, rest both sides of their brain simultaneously, sleeping with both eyes shut.