Features revisions of comprehensive coverage in previous editions on such topics as taxonomy, systematics, evolution, anatomy/morophology, behavioral and physiological ecology, and more, as well as new content on topics of anthropogenic concern and modern infomation on the results of emerging threats, such as ocean noise (including intensive navy, industrial and other sources), impacts of climate change and cutting-edge research and results on various aspects of evolutionary biology. Prev. ed.: 2008.