My PhD supervisor, Michael Day, died on June 1st, 2018, aged 91. Until a few months before his death, from the complications of bowel cancer, he was fit and well. Indeed, the last time we saw each other was last year at his house in Kelsale, Suffolk, when I helped him retrieve one of his beloved Labradors from a mud-filled moat! He was on good form, so much so that he had not long before played real tennis1 with his long-standing tennis partners. What follows borrows very heavily from an obituary I prepared for publication in the American Journal of Physical Anthropology, but, for reasons beyond the control of the editor, its publication has been delayed.
After Michael Day retired from the Chair of Anatomy at St. Thomas’ Hospital Medical School in 1989 he remained active to the extent that he was affiliated with the Palaeontology Department of the Natural History Museum in London, and as recently as 2013 he was a keynote speaker, and a much appreciated contributor, at an international workshop on the Function and Evolution of the Human Foot we organized here at GW. Although he did stray into both fossil and extant primates beyond those closely related to modern humans, Day’s main, important, and lasting contributions were the interpretation of fossil evidence germane to our understanding of the evolution of bipedal locomotion within the hominin clade.
Day was born on March 8th in the North Kensington district of London. After attending Sevenoaks School in Kent he did his mandatory National Service in the Royal Air Force from 1945 until 1948. Day was posted to the Middle East where fortunately, given his life-long interest in -- and aptitude for -- all things mechanical, he serviced the engines of Lancaster bombers and Spitfire fighters.
After his National Service Day, he entered the Royal Free Hospital School of Medicine (RFHSM) where he earned his medical qualifications in 1954. His plan was to be an orthopaedic surgeon, so after four years of working as a clinician he joined the Anatomy Department of the RFHSM with the intention of re-taking the first part of the surgical fellowship, a necessary qualification for a career as a consultant orthopaedic surgeon. But by 1958, John Napier had established the Unit of Primatology and Human Evolution within the RFHSM Anatomy Department, and Day discovered that for someone interested in the mechanics of the skeleton the study of human evolution provided an alternative career. So he abandoned his plans for a career in orthopaedic surgery and instead registered for a PhD at The University of London, successfully defending his impressive thesis on The anatomy of the lumbo-sacral plexus with particular reference to the blood supply in 1962. Day’s first solo publication in 1960, describing a case of median nerve compression, combined his original interest in orthopedics with John Napier’s interest in the hand. In the following year he published a paper with Napier on one of the short muscles of the thumb. But from that point on, apart from a 1964 publication on the blood supply to the lumbar and sacral plexuses in the fetus (another indication of his dexterity), nearly all of Day’s publications were devoted to human evolution.
After WW2 the center of gravity of human evolution-related research in the UK was Wilfrid Le Gros Clark’s research group based in the Department of Anatomy in The University of Oxford. But by the early-1960s Solly Zuckerman, who had been appointed to the Sands Cox Chair in the University of Birmingham just as WW2 was beginning, but who remained in the Oxford department until 1946, had established his own rival research group in Birmingham. Zuckerman’s wartime involvement in what became known as operations research brought him in contact with newly-developed quantitative methods, so he recruited researchers and students with an interest in, and an aptitude for, morphometrics. Before long the Birmingham and Oxford groups were in not-so-friendly competition. Zuckerman’s publications2 do not try to hide his disdain for what he considered was Le Gros Clark’s more traditional and outdated approach.
Le Gros Clark, who had been impressed by John Napier’s work on peripheral nerve injuries and his interest in functional morphology, recruited him to help in the interpretation of the limb bones of Proconsul africanus that had been recovered by Louis and Mary Leakey from Rusinga Island, Kenya. So when Louis Leakey sought advice about whom he should invite to interpret the early hominin postcranial bones that he and Mary Leakey had been recovering from Bed I in Olduvai Gorge, it was not surprising that Le Gros Clark would recommend Napier. He, in turn, recruited two of his then junior colleagues at the RFHSM Anatomy Department, Day and Peter Davis, to help him.
Both hand and foot bones had been recovered from localities in Bed I at Olduvai, but the 1964 Day and Napier paper concerned only the latter. Their conclusion, that the OH 8 foot belonged to an individual that possessed “the structural requirements” … “for an upright stance and a fully bipedal gait” (Day and Napier, 1964, p. 10), was an important component of the argument that Leakey, Tobias and Napier (1964) advanced for including OH 8 in the hypodigm of a new species, Homo habilis, they had controversially decided to include in Homo, rather than assign it to Zinjanthropus boisei, which had been recognized just five years earlier. In 1966 Day collaborated with John Napier to describe a distal hallucial phalanx, OH 10, but that was to be their last joint publication. Although Day subsequently wrote about the taxonomic admixture within the OH 7 collection of hand bones, the interpretation of true- and ichno-fossils (i.e., footprint trails) of the foot would continue to be a major focus of his career.
By the mid to late 1960s Louis Leakey had effectively handed over research at Olduvai to Mary Leakey, and Day became in effect Mary Leakey’s “anatomist of choice,” so when more hominin limb bones were recovered, or recognized, at Olduvai Gorge he was the one she asked to describe and interpret them. Day’s 1969 paper showing that the OH 20 proximal femur matched the morphology Napier (1964) had identified on the SK 82 and 97 proximal femora from Swartkrans3 was crucial evidence linking the hominins recovered from eastern and southern Africa. Subsequently, his meticulous 1971 description and analysis of a femur and a pelvis (OH 28) from Bed IV at Olduvai Gorge led to an interest in the postcranial remains of Homo erectus from China and Java (Day and Molleson, 1973). When 3.66 Ma fossil hominin footprint trails were uncovered at Laetoli in 1978, predictably Mary Leakey turned to Day for their analysis. His 1980 report (together with Wickens) using photogrammetric methods to compare the fossil footprints with modern human footprints is a landmark paper that deserves more recognition than it has received judging from the number of times it has been cited. Day wrote elegantly and clearly, and his reviews of early hominin postcranial fossils (Day, 1976a, 1976b, 1978, 1986) are essential sources for anyone retracing the history of ideas about the evolution of hominin locomotion. A colleague recently suggested that Day’s descriptions of fossils were particularly valuable because he did not make the mistake of confusing evidence with interpretation, and when he did offer an interpretation he was careful to point out alternatives.
Day’s descriptions and analyses were not confined to the postcranial skeleton. His 1969 response to Richard Leakey’s invitation to reconstruct and analyze the Omo crania, which would turn out to be the earliest unambiguous evidence of modern human cranial morphology, and his 1980 analysis (with Cassian Magori) of the Ngaloba cranium from Laetoli, were seminal contributions. Later he collaborated with Chris Stringer in an attempt to specify acceptable ranges of morphometric variation for the cranium of Homo sapiens (Day & Stringer, 1991). Looking at his list of publications, it is astonishing how productive he was in the decade between the mid 1960s and 1970s.
In 1962 Day moved from the RFHSM to The Middlesex Hospital Medical School (MHMS), where he rose through the academic ranks, becoming a University Reader in Physical Anthropology in 1969. In 1972 Day was appointed to the Chair of Anatomy at St. Thomas’s Hospital Medical School (STHMS), where he remained until his retirement in 1989. It was a matter of quiet satisfaction to him that one of his predecessors at STHMS was Le Gros Clark. It was around the time of the move to the STHMS that Day was part of a small group of anatomists invited by Richard Leakey to help describe and interpret the hominin fossils that Leakey and his team were recovering from what was then called East Rudolf in Northern Kenya.
At a relatively early stage in his career Day recognized there was no English language publication that summarized the fossil evidence for human evolution in the manner of Vallois and Movius’ Catalogue de Hommes Fossiles. So he prepared his own highly successful version of Vallois and Movius, which he called the Guide to Fossil Man. The pace of discovery of hominin fossils was such in the 1970s and 1980s that Day prepared four editions of the guide, the last in 1986. The Guide to Fossil Man provided masterful summaries of both hominin sites and the major hominin fossils recovered from each site. It was deservedly popular.
Day played an active role in several professional organizations. He was elected President of the Primate Society of Great Britain (1976-1979) and the Royal Anthropological Institute (RAI) (1979-1983). It was unusual for the RAI to elect a biological anthropologist as its President, and even more unusual to elect one for two terms. In 1979, when he assumed the Presidency, the long-term future of the RAI was far from assured, but thanks to his hard work and pragmatism, by the time he relinquished the Presidency in 1983 its fortunes were substantially improved. Day was politically committed to enhancing inclusivity in scientific life, and in particular to opposing the apartheid regime in South Africa. He was the chair of the first World Archaeological Congress (WAC) held in Southampton in 1986, and in 1989 he led a campaign under the WAC to formalize a code of ethics for researchers and others who deal with skeletal remains (Vermillion Accord on Human Remains, 1989).
Day, who was one of my anatomy teachers at the MHMS, introduced me to human evolution. He encouraged my interest by suggesting I investigate the OH 8 talus for my undergraduate project, and he was the one who brokered my involvement with Richard Leakey’s 1968 expedition to East Rudolf. As befits his generation, his style, mentoring and otherwise, was formal and I regret I was unable to penetrate that formality to get to know him better. With the enormous benefit of hindsight, he taught me more than I was prepared to admit to him-- I just hope he understood how much I owe him.
Michael Day, uniquely, had close scientific connections with two generations of the Leakey family. His death not only brings to an end a distinguished career , but it also closes a chapter in a sequence of prominent British anatomists who played leading roles in interpreting the fossil evidence for human evolution.
4 Michael Day's list of publications
Day, M.H. (1969a). Femoral fragment of a robust australopithecine from the Olduvai Gorge, Tanzania. Nature, 221, 230–233.
Day, M.H. (1969b). Omo human skeletal remains. Nature, 222, 1135–1138.
Day, M.H. (1971). Post-cranial remains of Homo erectus from Bed IV, Olduvai Gorge, Tanzania. Nature, 232, 383–7.
Day, M.H. (1976a). Hominid postcranial remains from Bed I, Olduvai Gorge. In G.Ll. Isaac, & E.R. McCown, Human Origins: Louis Leakey and the East African Evidence (pp. 363-374). Menlo Park, CA., USA: Benjamin Inc.
Day, M.H. (1976b). Hominid postcranial remains from the East Rudolf succession: a review. In Y. Coppens, F.C. Howell, G.Ll. Isaac, & R.E.F. Leakey, Earliest Man and Environments in the Lake Rudolf Basin: Stratigraphy, Paleoecology and Evolution (pp. 507–521). Chicago, IL., USA: University of Chicago Press.
Day, M.H. (1978). Functional interpretations of the morphology of postcranial remains of early African hominids. In C. Jolly. Environment, Behavior and Morphology: Dynamic Interactions in Primates (pp. 311-345). London, UK: Duckworth.
Day, M.H. (1986). Functional interpretations of the morphology of postcranial remains of early African Hominid locomotion¾From Taung to the Laetoli Footprints. In P.V. Tobias. Hominin Evolution¾Past, Present and Future (pp. 115-127). New York, USA: Alan Liss Inc.
Day, M.H., Leakey, M.D., & Magori, C. (1980). A new hominid fossil skull (LH18) from the Ngaloba Beds, Laetoli, Northern Tanzania. Nature, 201, 55–56.
Day, M.H., & Molleson, T.I. (1973). The Trinil femora. In M.H. Day. Human Evolution. Symposia of the Society for the Study of Human Biology (pp. 127–54). London, UK: Taylor & Francis.
Day, M.H., & Napier, J.R. (1964). Hominid fossils from Bed I, Olduvai Gorge, Tanganyika: fossil foot bones. Nature, 201, 967–70.
Day, M.H., & Napier, J.R. (1966) A hominid toe bone from Bed I, Olduvai Gorge, Tanzania. Nature, 211, 929–30.
Day, M.H., & Stringer, C. (1991). The Omo Kibish cranial remains and classification within the genus Homo. L'Anthropologie, 95 (2–3), 573–94.
Day, M.H., & Wickens, E.H. (1980). Laetoli Pliocene hominid footprints and bipedalism. Nature, 286, 385–387.
Leakey, L.S.B., Tobias, P.V., & Napier, J.R. (1964). A new species of the genus Homo from Olduvai Gorge. Nature, 202, 7–9.
Napier, J.R. (1964). The evolution of bipedal walking in the hominids. Archives of Biology (Liege), 75, 673–708.