Considerations

• One dolphin can't represent the entire species (and there are about fifty species of dolphins). Just like with humans, some dolphins are smarter than other dolphins. Tests for species intelligence are usually done on many individuals in order to determine an average.
  
  

Identification

• Dolphin using a sponge as a nose protector. Image from Animalintelligence.org
  
  Signs of intelligence include communication skills, ability to learn, tool use and sense of humor. Dolphins use various combinations of sounds and body positions to produce communications with other dolphins. They learn patterns of behavior to help them survive, whether it's fishing for themselves or performing tricks to get fish given to them. Dolphins use tools (see Resources). Dolphins also exhibit a sense of humor, performing pranks on other dolphins and blowing water rings.
  
  

Significance

• Comparing human accomplishments (like going to the moon) to dolphin accomplishments (never built a rocket to the moon) is not an adequate way to measure intelligence. What survival need would a dolphin have that going to the moon would accomplish? The lifestyles of humans and dolphins are so different that it's hard to find commonalities to make comparisons. Perhaps dolphins are a lot happier than humans could ever be. But, as of yet, science cannot measure happiness in animal species.
  
  

Size

• Human brains and dolphin brains are about the same size, with the dolphin having a 25% heavier brain than the average person. Brain size is usually determined by a brain-to-body-size ratio. In that ratio, humans have the bigger brain. However, humans have two-lobed brains while dolphins have four-lobed brains. Both are very wrinkly, which indicates a capacity for memory storage.
  
  

Theories/Speculation

• Dolphins and humans are about equal in intelligence. They are both able to master their surroundings to maximize survival. They also communicate, manipulate objects to perform tasks and have an incredible ability to learn. Both dolphins and humans learn through imitation. According to zoologist Anuschka de Rohan, a nursing baby dolphin watched a human smoking, drank a mouthful of milk and than spat it out to mimic the smoker ("Deep Thinkers", The Guardian 3 July 2003).