Intelligence is problem solving ability.  Intelligence is that faculty of Consciousness pertaining to the Mental Body.  The more highly developed the mental body, the greater the intelligence.  Intelligence can express itself in patterns of behaviour – e.g. ants building an ant-mound, or in problem-solving exercises – e.g. a chimpanzee poking a stick into the aforementioned ant-mound to get at the juicy ants.

Intelligence may be flexible and learned – in which case it is intelligence strictu sensu – for example primate (including human) intelligence, and pertains to an individual mental body.  Or it may be innate – e.g. the instinctive behaviours of ants, bees and termites, in which case it is refered to as instinct, and pertains to a collective or devic mental consciousness.

 Cephalopod brain size

 Evolution of Vertebrate Intelligence

 Social Insects

 Human Intelligence

 The Brain