Its pretty great that so many branches of life, at least currently, seem to be developing intelligence (mammals, birds, octopus, even some fish). I'd really be

Its pretty great that so many branches of life, at least currently, seem to be developing intelligence (mammals, birds, octopus, even some fish). I'd really be curious to know how intelligent multi-cellular species from the past were. In my mind this suggests that there is some serious selection pressure for intelligence in evolution, at least here on Earth. If pressures were similar on other planets, mammalian-level intelligence might be fairly common among multi-cellular life on other worlds.