This book appeared to be excellent at first glance, but there are a number of factual errors on pages 77 and 78 concerning human quadrupedalism. Human quadrupedalism was discovered and described by me, Uner Tan, in 2005 (1), and was later given the name of Unertan syndrome (UTS), which is associated with quadrupedality, primitive language, and severe mental retardation. Yet chapter 4, which describes human quadrupedalism, does not even mention Unertan syndrome, even though it is described, and the references on page 77 do not include my original or later papers on the subject. Instead the references cite a 2005 paper by Humphrey, Skoyles, and Keynes, published by the School of Economics in London.

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