Thanks. I can see that. However, I wonder if the study included fish and arachnids? :) At some point a line was drawn based on taxonomical definitions. It seems to me, the question is not whether or not animals sacrifice gut for brain, but whether 'gut for brain' was a niche that humans filled, or if the inverse change of the two was coincidence. It doesn't seem to be possible to answer that question by analogy unless all species included in the data set could explore the niche to begin with. Glad that I'm not an evolutionary biologist. :)At the same time I'm also weary of special pleading. The "refuting" paper noted that for the expensive tissue hypothesis to remain viable we must propose unique mechanisms operating in humans, which Occam's Razor doesn't like.