Studied animal behaviour under Prof. Niko Tinbergen (FRS, Nobel Laureate) at Oxford. Co-founder of the Serengeti Research Institute, Tanzania, where he carried out research over seven years, before returning to Oxford, and later to the Institute of Terrestrial Ecology in Banchory, Scotland. After becoming Senior Principal Research Officer, he retired as emeritus in 1997. Awarded the scientific medal of the Zoological Society of London and the scientific medal of the British Mammal Society, he obtained a DSc from the University of Aberdeen and was made Honorary Professor, University of Aberdeen in 1998. He has carried out research projects on mammals and birds on all continents, published 6 previous books and some 120 scientific papers. He has studied otters in the field for over 20 years, and published about 40 papers and one previous book on the ecology of otters.