Rio

Rio the Californian sea lion has been impressing scientists with her mental prowess for over 25 years and was the first non-human animal to demonstrate a level of logical thinking once found only in humans.

Rio was born at the Long Marine Lab, Santa Cruz, California in 1985 and reared by a human surrogate mother.

She’s learned to recognise numbers, the entire alphabet and gained notoriety when she became the first non-human to demonstrate what scientists call ‘equivalence classification’ - a level of logical thinking once found only in humans.

Having learned that A goes with B, and that B goes with C, Rio made a mental leap and deduced that A also goes with C. Using this logical reasoning Rio slowly built up a knowledge of the categories we recognise as numbers and letters.