Regarding brain size, there is a very nice TED talk: http://www.ted.com/talks/suzana_herculano_houzel_what_is_so_special_about_the_human_brain.html http://www.

Regarding brain size, there is a very nice TED talk: http://www.ted.com/talks/suzana_herculano_houzel_what_is_so_special_about_the_human_brain.html http://www.ted.com/talks/suzana_herculano_houzel_what_is_so_... The speaker argues that while there are animals with brains bigger than ours, their neuron density is lower; overall, humans have the highest number of neurons. She goes on by noting that the energy that the brain consumes depends only on the number of neurons, not the size, thus making humans the species that has the most energy-hungry brain. This leads to some interesting theories on how the evolution of our brain is related to our nutrition habits, which I found quite mindblowing.