Going on diet I'd say that the Koala is pretty brainless. Eucalyptus doesn't exactly stimulate the nervous system and the slow-moving, dopiness can only be attributed to this diet.

Yes, they can get vicious but that doesn't necessarily imply any higher plane intelligence.

Speaking of octopods my photography lecture last night was about Natural History and there was one interesting fact which came up. All living creatures on earth are carbon-based except for octopods which are copper based. This explains their ability to change colour so quickly. What I'd like to know is how the hell they managed to evolve!