Robert McNeill Alexander

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R. McNeill Alexander
Robert McNeill Alexander with Dinosaur.jpg
Demonstrating a biomechanics point with a dinosaur model
Died 21 March 2016 Edit this on Wikidata

Robert McNeill (Neill) Alexander, CBE FRS[1] (7 July 1934 – 21 March 2016) was a British zoologist[2][3][4] and a leading authority in the field of biomechanics. Until 1970, he was mainly concerned with fish, investigating the mechanics of swim bladders, tails and fish jaw mechanisms. Subsequently, he concentrated on the mechanics of terrestrial locomotion, notably walking and running in mammals, particularly on gait selection and its relationship to anatomy and to the structural design of skeletons and muscles.[1]

Education and early life[edit]

Born in Lisburn, Northern Ireland, Alexander was educated at the University of Cambridge (MA, PhD)[5] and the University of Wales (DSc).[4] His PhD research was supervised by James Gray.[2]

Career and research[edit]

After holding a lectureship at University College of North Wales from 1958 to 1969, he was Professor of Zoology at the University of Leeds from 1969 until his retirement in 1999, when the title of emeritus professor was conferred upon him.[6]

Alexander was secretary of the Zoological Society of London (1992–1999) which included supervising the management of London and Whipsnade Zoos. He was president of the Society for Experimental Biology (1995–1997), President of the International Society of Vertebrate Morphologists (1997–2001) and editor of the Proceedings of the Royal Society B (1998–2004).[7] Alexander specialised in research on animal mechanics and published numerous books and research papers in the field from 1959.

Dinosaur locomotion[edit]

Alexander was particularly interested in the mechanics of dinosaur motion.[8] He developed a formula to calculate the speed of motion of dinosaurs, the so-called 'dinosaur speed calculator,' mathematically derived from the Froude number:

"The key to deriving estimates of dinosaur gait and speed from trackways was provided by the zoologist R. McNeill Alexander (1976). From observations of modern animals he derived a general relationship between an animal's speed of locomotion (v) and its hip height (h) and its stride length (SL), which is
Alexander also pointed out that this formula could be applied to dinosaur trackways since the stride length can be measured directly and the hip height could be estimated from the size of the foot print."[9]

Originally, Alexander stated: "I have now obtained a relationship between speed, stride length and body size from observations of living animals and applied this to dinosaurs to achieve estimates of their speeds. The estimated speeds are rather low—between 1.0 and 3.6 ms−1."[10]

Modifications to the original formula gave rise to revised estimates, and "Alexander (1996) argued that based on the bone dimensions of Tyrannosaurus it is unlikely they could have travelled at more than 8ms−1."[11] Several calculations using variants of the formula indicate that dinosaurs probably travelled at around 3 ms−1 with a top speed of 8 ms−1. This translates to a speed range of roughly 6–20 mph.



  • Functional Design in Fishes, Hutchinson University Library, 1967, 1970
  • Animal Mechanics, Sidgwick & Jackson, 1968
  • Size and Shape, Edward Arnold, 1971
  • The Chordates, Cambridge University Press, 1975
  • Mechanics and energetics of animal locomotion, with G. Goldspink, Halsted Press, 1977
  • The Invertebrates, Cambridge University Press, 1979
  • Optima for Animals, Hodder Arnold, 1982
  • Locomotion of animals, Springer, 1985
  • The Collins Encyclopedia of Animal Biology, HarperCollins Publishers, 1986
  • Elastic Mechanisms in Animal Movement, Cambridge University Press, 1988
  • Dynamics of Dinosaurs and other Extinct Giants, Columbia University Press, 1989
  • Animals, Cambridge University Press, 1990
  • How dinosaurs ran, Scientific American, 1991
  • Animals, Cambridge University Press, 1991
  • The Human Machine, Natural History Museum, Stationery Office Books, 1992
  • Exploring Biomechanics: Animals in Motion, W H Freeman & Co, 1992
  • Bones: The Unity of Form and Function, Macmillan General Reference, 1994
  • Energy for Animal Life, Oxford University Press, 1999
  • Exploring biomechanics: animals in motion, Scientific American Library, 1992
  • Hydraulic mechanisms in locomotion, in Body Cavities: Function and Phylogeny, pp. 187–198, Selected Symposia and Monographs, 8, Mucchi.
  • Principles of Animal Locomotion, Princeton University Press, 2003
  • Human Bones: A Scientific and Pictorial Investigation, with Aaron Diskin, Pi Press, 2004
  • Knochen! Was uns aufrecht hält - das Buch zum menschlichen Skelett, Spektrum Akademischer Verlag, 2006


(This is a small sample from over 250 papers[12])

  • The Densities of Cyprinidae J Exp Biol 36, June 1959, pp. 333–340.
  • Visco-elastic properties of the body-wall of sea anemones J. Exp. Biol. 39, 1962, pp. 373–386.
  • Adaptation in the skulls and cranial muscles of South American characinoid fish[13]
  • Estimates of speeds of dinosaurs[10]
  • Bending of cylindrical animals with helical fibres in their skin or cuticle[14]
  • Tyrannosaurus on the run[15]
  • Dinosaur biomechanics[16]
  • Biomechanics: Stable Running[17]
  • Orangutans use compliant branches to lower the energetic cost of locomotion[18]
  • Incidence of healed fracture in the skeletons of birds, molluscs and primates[19]
  • Biomechanics: Leaping lizards and dinosaurs[20]

Film & TV work[edit]

  • Horizon (1976) TV series documentary
  • The Hot-Blooded Dinosaurs (1976)
  • Walking with Beasts (2001) TV series documentary (principal scientific advisor)
  • The Future Is Wild (2003) TV series documentary
  • Extinct: A Horizon Guide to Dinosaurs (2001) TV documentary[21]

Honours & awards[edit]

Alexander received several awards and honours during his career including:

Personal life[edit]

Alexander married Ann Elizabeth Coulton in 1961.[4][23] He died in 2016 at the age of 81.[24]


  1. ^ a b c "Professor McNeill Alexander CBE FRS". London: Royal Society. Archived from the original on 2015-11-17.  One or more of the preceding sentences incorporates text from the website where:

    “All text published under the heading 'Biography' on Fellow profile pages is available under Creative Commons Attribution 4.0 International License.” --Royal Society Terms, conditions and policies at the Wayback Machine (archived 25 September 2015)

  2. ^ a b Biewener, Andrew A.; Wilson, Alan (2016). "R. McNeill Alexander (1934–2016) Zoologist who pioneered comparative animal biomechanics". Nature. 532 (7600): 442–442. doi:10.1038/532442a. 
  3. ^ Portraits of (Robert) McNeill Alexander at the National Portrait Gallery, London
  4. ^ a b c ALEXANDER, Prof. (Robert) McNeill. Who's Who. 2016 (online Oxford University Press ed.). A & C Black, an imprint of Bloomsbury Publishing plc.  (subscription required)
  5. ^ Alexander, Robert McNeill (2015). The physical properties of the teleost swimbladder (PhD thesis). University of Cambridge. 
  6. ^ R McNeill Alexander academic homepage at Leeds
  7. ^ International Society of Biomechanics, Newsletter March 2011
  8. ^ The Pterosaur Database
  9. ^ Dinosaur speed calculator, University of Sheffield Archived 18 May 2012 at the Wayback Machine.
  10. ^ a b Alexander, R. McN. (1976). "Estimates of speeds of dinosaurs". Nature. 261 (5556): 129–130. doi:10.1038/261129a0. 
  11. ^ Dinosaur Gait and Estimates of Speeds, University of Bristol
  12. ^ "Robert McNeill Alexander, zoologist - obituary". The Daily Telegraph. 3 April 2016. Retrieved 3 May 2016. 
  13. ^ Alexander, R. McN. (1964). "Adaptation in the skulls and cranial muscles of South American characinoid fish". Journal of the Linnean Society of London, Zoology. 45 (305): 169–190. doi:10.1111/j.1096-3642.1964.tb00493.x. 
  14. ^ Alexander, R.McN. (1987). "Bending of cylindrical animals with helical fibres in their skin or cuticle". Journal of Theoretical Biology. 124 (1): 97–110. doi:10.1016/S0022-5193(87)80255-2. 
  15. ^ Alexander, R. McNeill (1996). "Tyrannosaurus on the run". Nature. 379 (6561): 121–121. doi:10.1038/379121a0. ISSN 0028-0836. 
  16. ^ Alexander, R. M. (2006). "Dinosaur biomechanics". Proceedings of the Royal Society B: Biological Sciences. 273 (1596): 1849–1855. doi:10.1098/rspb.2006.3532. PMC 1634776Freely accessible. PMID 16822743.  open access publication – free to read
  17. ^ Alexander, R. McNeill (2007). "Biomechanics: Stable Running". Current Biology. 17 (7): R253–R255. doi:10.1016/j.cub.2007.02.001. 
  18. ^ Alexander, R.McN.; Crompton, R.H.; Thorpe, S.K.S. (2007). "Orangutans use compliant branches to lower the energetic cost of locomotion". Biology Letters. 3 (3): 253–256. doi:10.1098/rsbl.2007.0049. PMC 2464692Freely accessible. PMID 17439848. 
  19. ^ Brandwood, A.; Jayes, A. S.; Alexander, R. Mcn (2009). "Incidence of healed fracture in the skeletons of birds, molluscs and primates". Journal of Zoology. 208 (1): 55–62. doi:10.1111/j.1469-7998.1986.tb04708.x. ISSN 0952-8369. 
  20. ^ Alexander, R. McNeill (2012). "Biomechanics: Leaping lizards and dinosaurs". Nature. 481: 148–9. doi:10.1038/nature10797. PMID 22217939. 
  21. ^ Robert McNeill Alexander at the Internet Movie Database
  22. ^ The University of Leeds, Reporter 455, September 2000
  23. ^ The International Who's Who 2004, Europa Publications
  24. ^ University of Leeds, obituary notice
Professional and academic associations
Preceded by
Barry Albert Cross
Secretary of the
Zoological Society of London

Succeeded by
Paul H. Harvey