Kudos should go to the invertebrate with the strength and skill to screw a lid off a jar! No. 9 in our list is the octopus, one of the smartest creatures in the sea. This animal is still poorly understood, but scientists are constantly discovering new and impressive octopus abilities. They play, solve problems, navigate through mazes and have a respectable short-term memory. But how is an animal that belongs to the same class as the snail capable of such clever feats? It may be that the combination of strength, agility, curiosity and a lot of brainpower sets the octopus apart from its soft-bodied brethren.