This is the only available paperback dictionary of zoology. This dictionary is a comprehensive and up-to-date reference work on all aspects of the study of animals. Now, with over 5,000 entries, it is ideal for students and will be invaluable to amateur naturalists and all those with an interest in the subject. It is illustrated with clear line drawings, and supported by useful appendices on the genetic code, endangered animals, and SI units. It features wide coverage, including animal behaviour, ecology, physiology, genetics, cytology, evolution, Earth history, and zoogeography. Full taxonomic coverage of arthropods, other invertebrates, fish, reptiles, amphibians, birds, and mammals is provided. It is completely revised to incorporate the discovery of 'extremophiles' - organisms living in environments formerly considered impossibly hostile - and the toxonomic reclassification that this has entailed. It features entires on genetics, evolutionary studies, and mammalian physiology.