April 19, 2024
Dear Members of our Campus Community,
I write to share with you the sad news that Dr. John Damuth of our Department of Ecology, Evolution, and Marine Biology passed away on April 2.
A Research Biologist, he was known for his expertise in vertebrate paleontology and evolutionary biology, and especially for his pioneering research on the interspecific scaling of ecological population density with body mass among herbivorous mammals.
Our hearts go out to his wife, our colleague Professor Susan Mazer, and their family and friends, and to all who were fortunate to work with him and be inspired by him. He will be greatly missed by our university community. In his honor, our campus flag will be lowered on May 1.
I am honored to share the following tribute from his peers, provided by our Department of Ecology, Evolution, and Marine Biology.
John Damuth (1952-2024)
With great sorrow at the loss of a singularly sharp, clear-thinking, delightful, warm, witty, generous and wonderfully curious colleague and partner, we announce the passing of John Damuth, who died following 15 months of treatment to hold an insidious cancer at bay. John was an evolutionary biologist whose contributions included wide-ranging empirical, theoretical, and conceptual advances in the fields of comparative ecology, ecological allometry, levels of selection, macroevolution and paleontology.
John was a brilliant scientist whose wisdom extended not just to his academic endeavours, but also to his insights into people, culture and the world in general. John was born in Corpus Christi, Texas on August 18, 1952, and grew up in Prairie Village, Kansas, in Northport, Long Island and in Sewickley, Pennsylvania with his sister Laura and his parents John (John Douglas Damuth, Sr.) and Mary. John’s curiosity about the world was directed towards science and history as a young boy, when he began to develop what became particularly deep interests in the ancient world, physical anthropology, linguistics, evolutionary theory, and paleontology. In 1970 he went to Yale University to study for a B.A. in anthropology, and then in 1974 to the University of Chicago, where he earned his Ph.D. in evolutionary biology. John always considered himself to have been extremely lucky to have been Leigh Van Valen’s graduate student at Chicago, and he continued Leigh’s tradition of eclectic scholarship by combining vertebrate paleontology with theoretical evolutionary biology. In John’s own words, his approach was “to seek out and investigate general processes and mechanisms that can be used to make reliable inferences about the remote past, but are based on demonstrable regularities in the present day.” (see johndamuth.net)
While John was at the University of Chicago he first met Susan Mazer in 1977 through mutual friends at Yale; they soon became inseparable partners, living together in Davis from 1981 to 1985 while Susan completed her Ph.D. in plant evolutionary ecology at the University of California, Davis, and marrying in 1988. For 45 years, they were a devoted couple who took great delight in each other’s observations, critiques, and accomplishments.
Initially, John and Susan were both postdoctoral fellows at the Smithsonian Institution in Washington in the mid-1980s. They agreed that, no matter who first got a permanent faculty position at a research institution with a broad graduate program in evolutionary biology, the other would follow. Consequently, after Susan was offered a position at UC Santa Barbara in 1998, John accepted the position of Research Biologist in what was then the Department of Biological Sciences, and created a research career that worked for them both.
Although John began his career studying fossils, exploring the collections of Eocene and Oligocene mammals at the Field Museum, he soon found himself engrossed in the world of evolutionary biology, attracted to the challenge of finding and explaining regularities in community structure, specifically those relating to mammalian body size and population density (in both extant communities and fossil localities). John’s first publication, completed while a graduate student (Nature, 1981), on Population density and body size in mammals became an instant and lasting classic that continues to be frequently cited (1446 citations to date).
John’s most important and widely known ecological and evolutionary discovery, as first described in the 1981 paper, is widely referred to as Damuth’s Law. John’s characteristic humility prevented him from ever referring to this discovery as a “law”, but many other investigators have accepted this distinction, and a brief description of it will justify this level of recognition. John’s work on ecological allometries began with his discovery of the interspecific scaling of ecological population density with body mass among herbivorous mammals, which led him to realize that species’ energy use among these species (at the population level) is independent of body size within communities.
The math and logic underlying this realization are relatively simple. Among ecologically similar species (e.g., herbivorous mammals), population density scales as the negative 0.75 power of body mass. The astonishing significance of this relationship becomes apparent when one applies another well-known scaling relationship (Kleiber’s Law, discovered in the 1930s) to estimate, within communities, energy use by populations of species of different body sizes. Kleiber’s Law states that the interspecific relationship between individual basal metabolic rates scales with body mass to the power of positive 0.75; actual metabolic requirements of mammals living in nature similarly scale with body mass to the power of 0.75.
John realized that one could estimate species’ population-level energy use by multiplying a species’ population density (which scales as body mass to the power of negative 0.75) by its metabolic requirements (which scales as body mass to the power of positive 0.75). Given that the two exponents cancel each other out, this means that the energy used by, say, a local population of herbivorous mammals in a community is independent of their body size. This independence of species’ energy use and body size is called the “energy equivalence of species” and is the essence of Damuth’s Law, which has since been demonstrated in many habitats, guilds and trophic levels. John later published (2007, The American Naturalist) a macroevolutionary explanation and mechanism for maintaining energy equivalence in natural communities. One of the most important implications of Damuth’s law is that, with respect to the ability of a population to capture energy, there is no optimum body size. This conclusion helps to explain the enormous and persistent variation (and lack of convergence) among species in body size within communities, guilds, habitats, and higher taxa over millennia.
John’s later research included advances in the analysis of multilevel selection, contextual analysis, the size-scaling of metabolism and the geometry of transport networks. These complex and over-arching topics in evolutionary biology became his primary areas of research and publication, although he maintained a strong interest in the details of mammalian evolution, in particular: dental anatomy and the reconstruction of paleodiets, including the estimation of tooth wear rates and hypsodonty; the estimation of body mass in extinct species; life history allometry; and changing community structure in relation to Neogene climatic changes. Over the past few years, John worked with Lev Ginzburg to complete a book entitled “Nonadaptive selection: An evolutionary source of ecological laws”, which will be published later this year by the University of Chicago Press.
John was extremely efficient in quantitative analysis and computerized databases, especially in relational database design and implementation. John served in numerous advisory roles on a diversity of database issues. Perhaps most importantly, he was instrumental in the early days (early 1990s) of the Ecology of Terrestrial Ecosystems (ETE) project at the Smithsonian and designed their initial relational database. The ETE database is the foundation for the paleontological databases NOW (New and Old World Mammals) and the PBDB (the Paleobiology Database), both of which are vital to the present-day world of paleontology. John maintained his involvement with the NOW database, as an active member of their advisory board from 1995 until his death.
Although John was not a prolific publisher, his papers have been extraordinarily influential, largely due to his innovation, insights, and the clarity of his writing; at an early age (his 40s) he had already gained the accolade of “the granddaddy of macroevolution”. In the field of mammalian paleobiology, several contributions stand out. His 1990 book (co-edited with Bruce MacFadden), Body Size Estimation in Mammalian Paleobiology, has been cited over 500 times: it is still in print, and remains a vital resource for current researchers. In 1992, in the ETE book (Terrestrial Ecosystems Through Time: Evolutionary Paleoecology of Terrestrial Plants and Animals), John invented the notion of a “taxon-free” characterization of elements in past communities, a vital break-through in thinking in this area. In 1998 John also obtained funding for a National Center for Ecological Analysis and Synthesis (NCEAS) working group on Inferring Climate and Vegetation from Mammal Communities. This involved two group meetings in Santa Barbara, and set the scene for a splendid international collaboration.
John was always an insightful and colorful presence at scientific meetings, easily recognizable by his penchant for well-made hats and patterned shirts. In addition to science, John also had a keen interest in World War II history and memoirs as well as the Civil War; he was a voracious reader of many books on both and was an amateur expert with a steel-trap memory. John’s culinary skills were legendary, and he applied them to recreating dishes from the various countries that he and Susan visited (China in particular). His pastrami, brisket, ribs, and Peking duck rivalled those of any dedicated BBQ, domestic or foreign. Finally, he was also an expert mixologist, with a home bar containing all the necessary equipment, accessories, and ingredients (such as bitters), for making eclectic cocktails. The kind of detail, attention, enthusiasm, and generosity that John paid to his creation of meals and cocktails reflected the same attributes he applied to his scientific research.
John’s passing is a blow to evolutionary biology and paleontology, as well as a staggering loss to his family and friends.
Christine M. Janis, Honorary Professor, University of Bristol (UK), Professor Emerita, Brown University (USA)
Blaire Van Valkenburgh, Professor Emerita, University of California, Los Angeles, Fellow, American Academy of Arts and Sciences; Fellow, American Association for the Advancement of Sciences; Honorary Fellow, California Academy of Sciences
Susan J. Mazer, Professor of Ecology and Evolution, University of California, Santa Barbara
Lev R. Ginzburg, Professor Emeritus, State University of New York, Stony Brook; President, Applied Biomathematics
Sincerely,
Henry T. Yang
Chancellor