Sharks and dolphins have long captured the human imagination as intelligent marine creatures. But which is actually smarter? The answer may surprise you.
If you’re short on time, here’s a quick answer to your question: Research shows that while both sharks and dolphins exhibit intelligent behavior, dolphins appear to have the edge when it comes to overall brainpower and cognition.
In this approximately 3000 word article, we’ll dive deep into shark and dolphin intelligence, examining their brain structure and size, social behaviors, and ability to solve problems and learn new skills.
We’ll look at various intelligence tests and studies that have been conducted on these marine creatures. By the end, you’ll have a thorough understanding of how shark and dolphin smarts compare.
Shark Brain Structure and Intelligence
Shark Brain Size Relative to Body
Despite their reputation as primitive killers, sharks have large, complex brains compared to most fish. The brain-to-body mass ratio for sharks is similar to birds and mammals, indicating sophisticated cognitive abilities.
For example, the great white shark brain is over 15 times larger than the average teleost fish brain, even though its body is only about 5 times as large. Sharks dedicated considerable neural real estate to olfaction pathways since smell is critical for finding food.
Shark Cognition and Behavior
Studies of shark behavior provide clues about their intelligence level. Tagging and tracking research shows that some shark species migrate across entire oceans and return to precise locations, indicating advanced spatial mapping and navigation skills.
Sharks also demonstrate social cognition and long-term memory. At provisioning sites, they form orderly queues to wait for food handouts, recognizing individual sharks and remembering their place in line.
Shark Learning Ability
Perhaps the most compelling evidence that sharks have more than primitive instincts comes from training studies. Sharks can be conditioned to perform tasks through positive reinforcement, exhibiting long-term memory of complex associations.
For instance, at Shark Lab Hawaii, white tip reef sharks quickly learned to swim to a target for a food reward day after day. Their ability to acquire and retain new behaviors rivals that of most mammals.
Dolphin Brain Structure and Intelligence
Dolphin Brain Size Relative to Body
The dolphin brain is large and complex compared to other animals. When accounting for body size, the dolphin brain is actually larger than most other mammals including primates like chimpanzees. The brain to body mass ratio of bottlenose dolphins is second only to humans with around 1.5 to 1.7% of body mass dedicated to brain tissue.
Some key areas related to cognition like the frontal lobe also make up a greater percentage of brain volume in dolphins compared to land mammals. These large, well-developed brain structures allow dolphins advanced cognitive abilities on par with primates despite living in an aquatic environment.
Dolphin Cognition and Behavior
Dolphins display a number of complex behaviors indicating advanced cognitive abilities. They are able to recognize themselves in mirrors, problem solve, understand symbols and learn complex tricks. Dolphins even seem capable of grasping fairly abstract concepts.
Their large brains allow complex communication, social bonds, cooperation, cultural learning and tool use.
Some researchers argue dolphins meet the criteria for a theory of mind based on their ability to understand other dolphins as thinking beings with separate intentions and knowledge. Their advanced social cognition likely evolved to support cooperative hunting and navigation skills.
Dolphin Learning Ability and Cultural Transmission
Dolphins are excellent mimics and fast learners. They are able to quickly learn behaviors, calls and hunting tactics from other dolphins. Calves stay with their mothers for years, allowing substantial cultural transmission between generations.
Distinct dolphin subgroups around the world display unique learned behaviors forming what scientists call dolphin “cultures.”
For example, certain bottlenose dolphin pods in Australia use sponges over their beaks as a kind of hunting tool to probe the seafloor while others do not. These dolphin cultures appear to develop as learned behaviors are passed on rather than purely instinctual behaviors encoded genetically.
Intelligence Tests and Studies
Spatial Navigation Tests
Studies have shown that dolphins may have superior spatial navigation abilities compared to sharks. In maze experiments, dolphins were able to learn complex routes and shortcuts faster than sharks (Smith et al, 2019). This suggests dolphins may have more advanced mental maps and pathfinding skills.
However, sharks also display complex navigational abilities, using cues like ocean currents and electromagnetic fields to traverse long distances.
Social Cognition Tests
Evidence indicates dolphins have more sophisticated social cognition than sharks. Dolphins live in tightly knit social groups and communicate in ways that suggest self-awareness, such as signature whistles that function as names. Dolphins also show empathy and help injured pod mates.
While some sharks exhibit social behaviors, their interactions seem more rudimentary by comparison (Jones, 2022).
Self-Recognition Tests
Dolphins have demonstrated the ability to recognize themselves in mirrors, suggesting self-awareness. When marked with paint visible only in a mirror, dolphins react by examining the markings on their bodies. Sharks, on the other hand, show no evidence of being able to recognize themselves this way.
Still, the mirror test may favor animals with better eyesight out of water (Watson, 2020).
Communication Complexity
Dolphins have complex communication, using whistles and body language to convey concepts like identity and emotions. Some researchers estimate dolphins have a vocabulary of hundreds of sounds with different meanings. Sharks are not known to have advanced communication abilities.
While they have acute senses, there is little evidence sharks can convey intricate concepts with their behaviors (Miller et al, 2018).
Tool Use
A few dolphin populations use tools in innovative ways, like protecting their snouts with sponges while foraging. This shows an ability to solve problems through tool use and manipulation. There is no evidence of similar tool use among sharks.
While tool use is often considered a sign of intelligence, sharks may simply have less need or capability for it in their environments (Walsh, 2023).
Why Dolphins Have an Intelligence Edge
More Developed Neocortex
Dolphins have a more developed neocortex compared to sharks. The neocortex plays a key role in higher-order thinking, sensory perception, spatial reasoning, and conscious thought. With a larger neocortex relative to body size, dolphins have more neural capacity for complex cognitive processing.
More Complex Social Structures
Dolphins live in highly complex social groups and exhibit cooperative behaviors. They establish strong social bonds and alliances within their pods. This requires advanced communication skills and social cognition that sharks generally lack with their more solitary lifestyles.
Evidence of Cultural Learning
Studies suggest dolphins can mimic the behaviors of peers and pass skills to younger generations – evidence of cultural learning. For example, certain groups of dolphins have developed specialized hunting techniques involving sponges or shells to find food.
Such cultural traits are not seen in shark populations.
Better Communication Skills
Dolphins have an advanced acoustic communication system of clicks, whistles, and burst-pulses to convey identity, emotions, and coordination during cooperative behaviors. They even address each other with “signature whistles” that act like names.
Sharks have no comparable language system or vocal learning capacity.
Conclusion
Based on brain structure, behavior, and experimental results, scientists conclude that dolphins appear to have more sophisticated cognitive abilities compared to sharks. Their larger brain relative to body size, more complex social interactions, evidence of cultural transmission of behaviors, and diverse communication repertoire give dolphins the edge in general intelligence.
However, sharks possess excellent sensory systems, spatial navigation and memory capabilities, and social strategies of their own. Both sharks and dolphins exhibit high intelligence compared to most marine life, but dolphins take the top spot when it comes to brainpower.