Dolphin intelligence

What is intelligence?

Intelligence can be defined as the ability to learn and apply knowledge; to understand new or challenging situations and the ability to think abstractly. Dolphins are notoriously talented mimics and quick learners; they demonstrate self-awareness, problem-solving, empathy, innovation, teaching skills, grief, joy and playfulness. It has become widely accepted that dolphins are highly intelligent animals which fascinates many people.

How intelligent are whales and dolphins?

Intelligence itself is hard thing to measure as we can’t use the same methods used to test humans, especially as they communicate very differently from us. A number of different approaches have been adopted to try and quantify the intelligence of dolphins, whales and other marine animals.

Ability to "learn"

One method that has been employed is the ease with which an animal can be trained. Dolphins and killer whales that learn tricks could be said to have intellect. The problem with assessing intelligence in this way is that we only have a human perspective. Tests on dolphins (or any other creature) are carried out to measure responses or reactions, which can be compared to humans. Therefore, the results are biased by the technique used, and may not accurately measure the original criteria of intelligence at all.

Brain size

Another method favoured by researchers to measure intelligence is to look at the brain. The picture below shows the comparative brains of a human, dolphin and cow.

Human (left), Dolphin (middle), Cow (right)

Whales and dolphins have large brains; brainy dolphins have a brain to body ratio second only to humans. The human brain is typically 3 times heavier than that of a cow, while sperm whales have brains more than five times the size of a human. As a percentage of body weight, the human brain accounts for 2.1% and the bottlenose dolphin 0.94%. Whales and dolphins have large brains. Large-brained creatures generally have a few things in common: they live long lives; they are sociable; their behaviour is complicated; females give birth to only a few offspring throughout their lives and take extraordinary care of each baby while teaching them life skills; the youngsters take their time to grow up, become sexually mature and independent of their mothers. However, brain size alone does not signify intelligence.

Brain complexity

Brain complexity has also been studied. Perhaps the most obvious difference between our brains and that of dolphins and all toothed whales is that they have an entire area dedicated to echolocation. Dolphins can “see” with sonar and this skill or superpower is called echolocation. Sound travels much better in water than light does and so it makes more sense for dolphins to "see" their surroundings with sound. Their echolocation abilities are phenomenal; they can determine extraordinary details about everything around them. They use echolocation to hunt and navigate even in dark or murky water. Dolphins can check out each other's pregnancies and eavesdrop on the echolocating clicks of other dolphins to figure out what they’re looking at.

Whales and dolphins have communication abilities that are superior to those of human beings. Dolphin communication is so great that there is a strong possibility that a dolphin can send a sound image of say a fish to other dolphins. They can communicate in ways we can’t even imagine

Whale and dolphin brains contain specialized brain cells called spindle neurons. These are associated with advanced abilities such as recognising, remembering, reasoning, communicating, perceiving, adapting to change, problem-solving and understanding. Also, the part of their brain which processes emotions (limbic system) appears to be more complex than our own.

Research into the human brain has revealed that the development of the cerebral cortex is also an important factor. This is where analysis of sensory information takes place and conscious responses to stimuli originate. The cerebral hemispheres in human and dolphins are both large and possess convoluted folding. However, the cerebral cortex is much thinner in dolphins than in humans and more closely resembles those found in cows and sheep. Whilst studies of dolphin brains have shown that they are less developed than a human brain they are more developed than other mammals such as chimpanzees.

Sense of self

The ability to recognise yourself in a mirror is often used by psychologists as a measure of intelligence and self-awareness. This skill is rare but besides humans, only bottlenose dolphins, chimpanzees, elephants and magpies have been shown to recognize themselves in a mirror. Human children start showing signs of self-recognition at about 12 months at the earliest and chimpanzees at 2 years old. Dolphins recognise themselves in a mirror even earlier, at only 7 months old.

Dolphins will inspect themselves and look at parts of their bodies in the mirror that they can’t usually see - such as inside their own mouths. They also muck about, twirling and posing in unusual ways, examining their own movements in the mirror. These behaviours indicate self-awareness of a highly intelligent species.

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