Dolphin

Dolphins belong to the order Cetacea and are highly social, intelligent marine mammals. They live in groups called pods and communicate using a sophisticated system of clicks, whistles, and body language. Dolphins have a large brain-to-body ratio and a highly convoluted neocortex — the region associated with advanced cognitive abilities, consciousness, and social behaviour. Their brains evolved in parallel with humans, developing similar complexity through a completely different evolutionary path.

The dolphin brain is remarkably complex. It has a highly folded neocortex similar to humans, which is associated with higher-order thinking, social behaviour, and communication. Dolphins also possess an enlarged limbic system, which plays a central role in emotional processing and empathy. Crucially, their brains are adapted for echolocation — a biological sonar system where the melon (a fatty organ in the forehead) focuses sound waves. The returning echoes are processed by large dedicated brain regions that build 3D acoustic images of their surroundings.

Dolphins demonstrate self-awareness — they can recognise themselves in mirrors, a test only a handful of species pass. They use tools (sponges to protect their snouts while foraging on the seafloor), solve puzzles, understand sign language syntax, and learn behaviours from each other — a rare form of cultural transmission. Each dolphin has a unique 'signature whistle' that functions like a personal name, and other dolphins call them by copying it. They have been observed grieving their dead and displaying altruistic behaviour toward injured pod members and even other species.