Reaching lengths of up to 67 ft. long, the sperm whale is the largest known whale within the toothed whale family. The sperm whale also happens to have the largest brain and cerebrum of any known mammal in existence today. In fact, the sperm whale’s brain weighs 5 times that of a human’s brain!
Although brain size has previously been used to correlate intelligence among various animal species, recent research has shown that brain size does not always equal high intelligence, so the sperm whales’ brain size cannot be used as the only determining factor of intelligence. However, despite whether or not their brain size has an impact on their intelligence, the cetacean family overall has displayed a high level of intelligence as a species.
For those who aren’t familiar with cetaceans, the cetacean species includes all whale, dolphin, and porpoise species. Most of what we know about cetacean intelligence has been gathered from research on dolphins. Unfortunately, most whale species are too large in nature to perform similar tests, so intelligence gathering is often limited to observations of large whales and tests performed on smaller cetacean species.
Among the dolphin population, researchers and trainers have performed various tests on their ability to learn comprehensive tasks, problem solves, and respond to various commands.
Dolphins have also shown the ability self recognize and observe markings placed on their body when facing a mirror, a characteristic that is common among only a few highly intelligent species. In fact, dolphins have even been trained by the military to locate underwater mines, and military personnel lost at sea.
Because dolphins and whales (such as the sperm whale) possess many of the same abilities and cognitive skills, it is likely that many of these same mental strengths also exist among the sperm whale species.
To help the sperm whale navigate the ocean and survive, these marine mammals are equipped with a pair of large retractable eyes and an enlarged auditory system to help find their way around. And because sound travels 4 times faster in water than it does on land, having excellent hearing can be essential to survival.
Furthermore, these whales possess excellent echolocation abilities. Some scientists believe the sperm whale’s large head and the waxy substance created from the spermaceti organ in their head may play a strong role in improving the whale’s echolocation by enhancing its ability to observe various acoustic sounds and measure its distance or direction about the whale’s position.
Echolocation allows these marine mammals to locate prey and navigate the ocean in complete darkness, which is especially useful for sperm whales since they often hunt for food in the dark.
Overall, sperm whales are considered intelligent marine mammals with highly specialized skills. However, the extent of their intelligence remains partially speculative due to a lack of our understanding of these amazing animals.
Brain Size and Intelligence
For a long time, brain size was correlated directly with intelligence. Even though considerably more is known about the brain than in the past, intelligence and brain size continue to be debatable among researchers and scientists. This continuing debate has to do with observations from different tests and case studies.
In one study, a group of city mice was compared to a group of country mice. They showed that mice that lived in the city had larger brains than those that lived in the city, which was believed to be a clear indicator of increased intelligence among city-dwelling animals that dealt with higher levels of cognitive stress. However, observations of other mammals showed little or no increase in brain size despite living in city/urban environments.
Interestingly several other animal species showed larger brain sizes in rural areas than those living in city environments, which challenged the nature vs. nurture theory and negated the idea that animals living in a city area are more intelligent than those in rural areas.
This research was considered compelling because there was a belief that animals that lived in areas where more intelligence is required for survival would grow larger brains to deal with the additional cognitive needs of living in such an area. However, this idea and others have since scrutinized more compelling arguments, and tests have been conducted.
Furthermore, while animals with larger brains such as elephants and whales show significant capacities for self-recognition, problem-solving, language, culture, and family, many researchers believe that they still have less cognitive capacities and intelligence than humans.
While there is no argument that these animals are intelligent, there are regular arguments regarding how intelligent they are and whether they are as intelligent as humans. Note: This article is created to show the arguments among the various theories and ideas related to intelligence and brain size and therefore is not created to be a biased opinion or argument of one side or the other.
Rather than basing intelligence on brain size alone, some researchers believe that a better correlate of intelligence or cognitive skill should be based on the size of specific parts of the brain and how they compare to the rest of the brain and overall body size.
Areas such as the frontal lobe, temporal lobe, parietal lobe, and visual/auditory systems, among others, may be measured separately to determine an animal’s level of performance related to that specif brain function.
Studies among children and adults show that when one part of the brain has abnormal growth/reduced size, it can alter the brain’s ability to function and enhance or reduce specific functions associated with that part of the brain. This can include sensory perception, emotional responses and capacity, motor skills, problem-solving, and memory, among other mental functions.
Individuals that suffer from mental disorders often show impairments in the specific regions of the brain where that specific skill is developed or used. By measuring the size of specific brain regions, researchers may better understand how a specific function performs compared to other species with smaller/larger regions.
To better understand the brain and its functions, tests are now often performed using MRI scans during specific activities to measure the brain’s response to certain impulses. Humans and monkeys are often the subject of MRI tests as their size, and cognitive capacities are often easy to compare and study.
From the research that has been performed on primates and other animals, some researchers believe that brain size, the size of the frontal lobes, gray and white matter, and overall thickness of the cortex may correlate with social bonding, culture, and interaction with other animals.
Under this theory, animals with larger and more developed brains can deal with a more complex social society and the stresses associated with bonding, culture development, and social interaction. Moreover, social intelligence may be associated with brain size and development as complex social interactions and culture result from higher intelligence. Finally, this idea suggests that brain size is correlated more with social development than motor skills.
If this theory is correct, then it can be concluded that brain size and development may have some correlation with intelligence, social bonding, and culture development among various animal species; however, this correlation only accounts for a portion of the animals level of intelligence as animals with smaller but more developed brains may show equal or higher levels of overall intelligence than those with larger brains.
When it comes to animals of the same species, brain size appears to be less of a correlate of intelligence as humans of various brain sizes have shown minimal correlations of intelligence relative to the size of their brain when compared to that of other human beings.