Bryan Shorrocks is an Honorary Professor in the Environment Department, University of York. He was previously Professor of Population Ecology at the University of Leeds, and is an Emeritus Professor of that University. For many years he was senior editor of the Journal of Animal Ecology, and for the past 5 years has been an editor for the African Journal of Ecology. He has twice been a member of the Council of the British Ecological Society, and has been on UK research committees for NERC and AFRC. He advises the Namibian Cheetah Project, is UK representative for the East African Wildlife Society, and is a Trustee of the East African Wildlife Trust. His current research at the Mpala Research Centre, in Laikipia, central Kenya focuses on reticulated giraffes in the region. He recently helped to supervise a giraffe project in Namibia, and was the script advisor for the Savannah programme in the BBC's 'Africa' series. During the last 26 years he has had 148 publications. William Bates studied initially at the University of Guelph followed by an MSc. in Zoology at the University of Western Ontario, and a Ph.D. in Zoology at University of Texas at Austin. He has held the following research positions: NSERC PostDoctoral Fellow at the University of Oxford, and Kyoto University, Assistant Professor at Carleton University 1989-1994, Research Scientist at Bamfield Marine Science Centre 1994-1999; Associate College Professor at Okanagan University College 1999-2005; Associate Professor at University of British Columbia 2005-2013; Emeritus Professor at University of British Columbia 2013-present. He has had over 50 publications and over $1 million in total of research support. He has had fourteen years of field work in Africa studying wildlife vocalizations.