Skip to content

A reminder of how Raymond Cowles and Charles Bogert modified how the world considered physique temperature regulation in reptiles


    An offprint on the market caught my eye. Shortly afterwards I had my first snug take a look at an essential piece of analysis revealed in wartime USA that I had quoted in my final-year pupil seminar in February 1965. I say snug as a result of all I had then was an incomplete pre-xerox photocopy that was tough to learn. After I learn the paper and appeared on the pictures, I appeared up the authors each in Contributions to the Historical past of Herpetology and on Wikipedia. Exhibiting how appallingly dangerous many zoologically primarily based articles on the latter are, an important work of the 2 authors doesn’t even get a point out.

    Raymond Bridgman Cowles (1896-1975) and Charles Michill Bogert (1908-1992) discovered from their research of desert lizards that the poikilothermic animals, often described as ‘cold-blooded’, are  not merely on the similar temperature as their environment. As a substitute, by day they use behavioural mechanisms to realize and keep a most well-liked physique temperature. When cool they transfer into, and orientate their our bodies in direction of, the solar. When too scorching, they transfer into shade and/or into burrows. Later, the popular physique temperature of a selected species was proven by Paul Licht to correspond to the optimum temperature for the exercise of key enzymes within the tissues.

    Cowles and Bogert’s analysis was enormously influential not solely in altering the prevailing views of how poikilothermic animals work but additionally in opening up a brand new area of physiological ecology. Certainly Cowles modified the nomenclature.  Poikilothermic (i.e. variable physique temperature) was taken to suggest that physique temperature was not regulated whereas homoiothermic was the time period used for the internally regulated fixed physique temperature of birds and mammals. He argued that the time period ‘ectothermic’ for animals akin to reptiles that depend on exterior sources of warmth to keep up their physique temperature was extra acceptable, with ‘endothermic’ for mammals and birds which generate their very own physique warmth.

    Raymond B Cowles
    from Contributions to Herpetology
    see under

    Cowles began the entire thing off. He was born to an American missionary household in South Africa. There, as a boy, he developed an curiosity in birds and reptiles and again within the USA his PhD thesis was on the life historical past of the Nile Monitor. Appointed to the College of California at Los Angeles (UCLA) in 1929 he got interested within the extinction of the dinosaurs. He developed the unconventional thought, after seeing the work of two buddies on the significance of physique temperature on the exercise of reptiles at evening and on the warmth tolerance of lizards and snakes, that dinosaurs have been worn out not by a fall in temperature on the finish of the Mesozoic however by an increase. He realised that he ought to examine thermoregulation in reptiles each within the area and within the laboratory and to that finish established a area station close to Indian Wells in 1939.

    In addition to his work in physiological ecology, Cowles was horrified by the consequences of over-population and campaigned vigorously. He noticed the consequences when he returned within the Fifties to the valley in South Arica the place he had lived as a boy. The land was over-grazed, barren and ripe for erosion and flooding. I discover astonishing the truth that his trenchant views on the expansion of the human inhabitants brought about him to change into unpopular—even a pariah—in his personal establishment and among the many common American public.

    Cowles remained at UCLA from 1939 till his retirement in 1962; thereafter he labored on the College of California in Santa Barbara.

    Charles M Bogert
    from Contributions to Herpetology
    see under

    Charles Bogert was a pupil of Cowles at UCLA within the mid-Nineteen Thirties, and like Cowles had vast pursuits in pure historical past. By the point he was collaborating with Cowles on thermoregulation in reptiles he was on the American Museum of Pure Historical past in New York. Unable to afford development to a PhD at UCLA, he had been appointed as assistant to Gladwyn Kingsley Noble in 1936. On Noble’s demise on the age of 46 in 1940, Bogert was appointed to move the herpetology division. There he continued the classical ‘museum fashion’ systematic research however continued with laboratory and area work in numerous areas, most notably on frog vocalisations and their organic significance. In 1966 UCLA awarded him an honorary LLD. He took early retirement in 1968, persevering with to write down however a sequence of strokes from 1988 and extreme arthritis debilitated and depressed him. He killed himself in 1992 at residence in Santa Fe, New Mexico.

    It has been a pleasure studying Cowles and Bogert’s seminal paper which they described as a ‘preliminary research’. It described the primary 4 years of their work  within the Coachella Valley which they described as ‘a desert of maximum warmth and aridity, characterised by sporadically plentiful annual, and scanty perennial vegetation’. The fashion of the publication, which appeared within the Bulletin of the American Museum of Pure Historical past, is extra discursive than that of a scientific paper with pictures of the terrain, experimental housing and a number of the animals they studied.

    A lot as been added over the 80 years since Cowles and Bogert have been busy within the Coachella Valley however some basic questions nonetheless stay. For instance, though some ectotherms might obtain their most well-liked physique temperature for a part of the day, they’re nonetheless poikilothermic—their physique temperature does fluctuate over the course of a day. Since temperature impacts all chemical processes, then there are implications for such physiological mechanisms as the inner organic clock, for processes like reminiscence and the motion of hormones. As well as, questions of ectothermy and endothermy in dinosaurs—the issue that first attracted Cowles to the thermal physiology of desert reptiles—are nonetheless a scorching matter.

    Cowles RB, Bogert CM. 1944. A preliminary research of the thermal necessities of desert reptiles. Bulletin of the American Museum of Pure Historical past 83, 261-296.

    Anon. 2014. Cowles, Raymond B (1896-1975). In Contributions to the Historical past of Herpetology (Quantity 1, revised and expanded), Edited by Kraig Adler, pp 116-117. Society for the Examine of Reptiles and Amphibians.

    Anon. 2007. Bogert, Charles M (1908-1992). In Contributions to the Historical past of Herpetology (Quantity 2), Edited by Kraig Adler, pp 178-180. Society for the Examine of Reptiles and Amphibians.

    Turner JS. 1984. Raymond B Cowles and the biology of temperature in reptiles. Journal of Herpetology 18, 421-436.