Recently, the Biology section of PF got a new thread, Cranial Size and Intelligence. One exchange in that thread concerned the 'intelligence' of species other than Homo sap. Clearly, not wearing a biologist's hat, each of us may be able to give a description of what we think the intelligence of another species might be, and these descriptions might have some common elements. But how do biologists use the term? For example, does it have a set of precise, technical meanings? Is there a set of standard techniques regularly used to measure the intelligence of species? Are there objective scales for intelligence (within the biological sciences)? Ernst Mayr, the famous evolutionary biologist, certainly used the term in his SETI debate with Carl Sagan. However, there he was addressing a non-technical audience, and likely used the word in its everyday meaning, not necessarily in any precise, biological sense. Can any biologist help here?