Derek Yalden was one of the pillars of British mammalogy (the study of mammals) and one of the outstanding zoologists of his generation. He was president of The Mammal Society for 16 years from 1997 and editor of its journal, Mammal Review, for 22, from 1980 to 2002. He published over 200 papers in refereed journals on subjects ranging from the ecology of mountain hares to the flight ability of the first bird, Archaeopteryx.
Fit, tireless and regarded as a zoological polymath, he was completely dedicated to his subject while never over-intellectualising it and remaining down to earth; hence, as well as a leading academic, he was also a very good ambassador for mammal study. A paper in British Wildlife, on the decline to extinction of our little-known feral wallabies and based on many years of patient fieldwork in the Peak District, was published a few days after his death while he was on a short holiday in the Forest of Dean.
Yalden is widely known for his editorship with Stephen Harris of the massive fourth edition of Mammals of the British Isles, a seminal, highly readable book on The History of British Mammals and a companion volume on The History of British Birds, which chart the ever-changing scene from the Ice Age (or, in the case of birds, the Jurassic) to the present day.
Much of his fieldwork was done at weekends or when everyone else was on holiday. It was usually centred in the Peak District. With his wife, Pat, whom he married in 1972, he studied moorland ecology as well as the behaviour and ecology of hares, owls, plovers and waders and other species. His long-term studies there have been used by others to analyse the effects of climate change in the uplands, and by the National Trust in restoring eroded peatland. His other centre of expertise was on the mammals of Ethiopia, on which he contributed a number of major papers as well as a seven-volume catalogue of resident mammals. Two species, the tree-frog Leptopelis yaldeni and the mouse-like Yalden's Desmomys, were named in recognition of his work there.
The young Derek Yalden lived in Hersham, Surrey from where he cycled five miles to school at Surbiton County Grammar. As a schoolboy he was a keen aero-spotter and a member of the Royal Observer Corps. It was at school that he met his lifelong friend and fellow zoologist Pat Morris. Together they studied badgers, foxes and other species in the south-west London area and their first joint paper, on a newly discovered colony of Edible Frogs, was published in 1961, when Yalden was a student and Morris still at school.
Yalden passed four A-levels and went on to University College London, graduating in 1962 with one of the few first-class honours degrees in zoology awarded by UCL in those days. He studied the carpal bones (wrist bones) of mammals at Royal Holloway College under Percy Butler, obtaining his PhD in 1965. From there he took up a post as lecturer at the School of Biological Sciences in the University of Manchester, where he remained for the rest of his 40-year career, specialising in vertebrate zoology.
In 1963, Yalden and Morris became keen supporters of the Mammal Society's Bat Group, which later led to their jointly authored book, The Lives of Bats. Inspired by John Clevedon Brown's lectures at Royal Holloway on the history of British mammals, Yalden became deeply interested in the past and present distribution of mammals and birds, which in turn led to a broadening of the traditional boundaries of zoology to embrace place-name evidence and archaeology.
He once reconstructed the wildlife of Cheshire 1,000 years ago from hints and clues in the Domesday Book and other sources. He was able to show that the White-tailed Eagle was once widespread in Britain. He also elucidated the mystery of why the Pygmy Shrew but not the Common Shrew is found in Ireland: the former is more at home in wet, peaty environments, which would have characterised the short-lived land bridge between Britain and Ireland. Yalden was one of the movers behind the first atlas of British and Irish mammals. It led also to his interest in feral and introduced species, such as the Red-necked Wallaby, and to his enthusiasm for re-introductions of lost members of our fauna, such as the beaver, lynx and wolf.
He was fascinated with the problem of the first bird, Archaeopteryx, and the debate about whether or not it could fly. In a series of papers he established its probable weight (250g to 300g, between a jackdaw and a rook in size). In his interpretation it could fly, but rather clumsily, and could use its long, sharp claws to climb trees. Archaeopteryx probably spent a lot of time on the ground, running and flapping its wings in the way young game birds do to escape predators.
Derek Yalden was tall, good-humoured and likable. At the market in Addis Ababa in 1968 he spotted an elaborate embroidered cape, which he bought and wore about town despite the strange looks he received. It was in fact a ceremonial donkey coat. Yalden enjoyed the joke and frequently wore it at special occasions at the University of Manchester; he was never one to take himself too seriously. He will be remembered with gratitude and affection by his many students both in England and abroad.
Derek William Yalden, zoologist: born Surrey 1940; lecturer, University of Manchester 1965-2005; reader in Zoology 2005-2013; President, Mammal Society 1997-2013; Editor, Mammal Review 1980-2002; Linnaean Society Medal 2010; married Pat Brayley 1972; died Forest of Dean, Gloucestershire 5 February 2013.