The 5 Smartest Non-Primates on the Planet
Octopuses Neat human trick:
Credit: Mattias Kabel
If pigs are the most intelligent of the domesticated species, octopuses take the cake for invertebrates. Experiments in maze and problem-solving have shown that they have both short-term and long-term memory. Octopuses can open jars, squeeze through tiny openings, and hop from cage to cage for a snack. They can also be trained to distinguish between different shapes and patterns. In a kind of play-like activity one of the hallmarks of higher intelligence species octopuses have been observed repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them.
The octopus is the only invertebrate which has been shown to use tools. At least four specimens have been witnessed retrieving discarded coconut shells, manipulating them, and then reassembling them to use as shelter.