[sandworm101]

>> can only judge brains by their impact on the world.

So bacteria? Plankton has a massive impact on the world too. Insects ... the planet is arguably dominated by insects.

Mammalian brains are, plus or minus a few percent, equally as dense/complex. There are aspects of dolphin brains that are far more complex than ours. A dog's brain has far more connections dedicated to smell than ours. There is some evidence that Orca brains have similarly more connections dedicated to emotions. Each brain is tuned slightly differently, ours perhaps more to vision and problem solving, but our biology isn't any more evolved or complicated.