HideShark list
Intelligence is hard to rank, because animals are smart in different ways — social intelligence, tool use, memory, problem-solving, communication. This list gathers the species with the strongest evidence across those measures, and it is not limited to mammals.
Tool cultures, planning, and social politics
Chimps make and use a regional tool kit — termite rods, nut hammers, spears — that varies between groups like human culture. They plan ahead, deceive rivals, form political alliances, and appear to grasp what others can and cannot see.
Full chimpanzee guide →Self-recognition, names, and taught tool use
Dolphins pass the mirror self-recognition test, give themselves individual "signature whistles" that others copy to get their attention, cooperate in complex hunts, and — in Shark Bay — carry sponges as tools, a skill passed from mother to daughter.
Full bottlenose dolphin guide →Culture, dialects, and inherited hunting tactics
Separate orca populations have their own dialects, diets, and hunting methods — beaching to grab sea lions, wave-washing seals off ice — taught across generations. Post-reproductive grandmothers lead pods to food in lean years.
Full orca guide →Long memory, mirror self-recognition, and mourning
Elephants remember individuals and water sources for decades, recognise themselves in mirrors, use tools, distinguish human languages and age groups by voice, and show sustained interest in the bones and bodies of dead elephants.
Full elephant guide →Problem-solving and tool use — in an invertebrate
With most of its neurons in its arms, an octopus opens jars, navigates mazes, remembers solutions, recognises individual people, and carries coconut shells to reassemble as armour — the clearest tool use known in any invertebrate.
Full octopus guide →Tool-making, planning, and face recognition
Corvids bend wire into hooks, make and carry compound tools, save tools for future use, solve multi-step puzzles, plan hours ahead for a reward, and remember specific human faces for years.
Full crows and ravens guide →Sign language and abstract concepts in captivity
Gorillas use few tools in the wild but have shown, in captivity, large sign-language vocabularies, an understanding of concepts like "sad" and "later," and — in wild groups — the use of sticks to test water depth and as walking aids.
Full gorilla guide →Mirror use and joystick-controlled video games
Pigs use information from a mirror to find hidden food, learn their names, remember locations, and have been trained to move a cursor on a screen with a joystick to hit targets for a reward.
Counting, categories, and the concept of zero
The African grey parrot Alex learned to label around 50 objects, seven colours, and shapes, to count to eight, to answer questions about "same" and "different," and to grasp the idea of zero — cognition once thought unique to primates.
Tool use, probability, and cooperation
The New Zealand mountain parrot makes tools, works out which container is the better bet, and coordinates with a partner to operate a device neither bird can work alone — matching great apes on several tests.
Full kea guide →Symbolic communication and collective decision-making
A honeybee tells hivemates the direction and distance to flowers with a symbolic dance, can learn to associate "less" with "left," and a swarm reaches an accurate collective decision about a new home by a scout-and-vote process.
Full honeybee guide →After humans, chimpanzees are usually named the most intelligent animal, closely followed by bonobos, dolphins, orcas, and elephants. But "smartest" depends on the test — octopuses and crows outperform many mammals on tool-based problem-solving.
It is genuinely debated and probably unanswerable. Dolphins have larger brains relative to body size and excel at social and vocal intelligence; chimpanzees show richer tool use and are our closer relatives. Both pass the mirror self-recognition test.
The octopus, by a wide margin. It solves novel problems, uses tools, shows curiosity and possibly play, and has a nervous system organised completely differently from a vertebrate brain.