# Robert McNeill Alexander

Robert McNeill Alexander, CBE, MA, PhD, DSc, FRS (born 7 July 1934, Lisburn, Northern Ireland) is a British Zoologist.

## Biography

Professor Alexander was educated at the University of Cambridge (MA, PhD) and the University of Wales (DSc). After a Lectureship at the then University College of North Wales (now Bangor University) 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.[1]

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 prestigious Proceedings of the Royal Society B (1998-2004).[2]

Alexander married Ann Elizabeth Coulton in 1961.[3]

Alexander has specialised in research on animal mechanics and apart from the books listed below, he has also published numerous research papers in this field since 1959. He is still an active research scientist and continues to publish papers regularly.

## Dinosaur locomotion

One particular area of his research interest has been into the mechanics of Dinosaur motion.[4] He contributed greatly to the development of a formula used to calculate the speed of motion of dinosaurs, the so-called 'dinosaur speed calculator,' which is in fact 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

${v}=0.25.{g^{-0.5}}.{SL^{1.67}}.{h^{-1.17}}$

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."[5]

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 m s−1."[6]

But 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."[7] 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.

## Publications

### Books

• Functional Design in Fishes, Hutchinson University Library, 1967, 1970, ISBN 0-09-104751-X
• Animal Mechanics, Sidgwick & Jackson, 1968
• Size and Shape, (Institute of Biology Studies in Biology), 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 H&S, 1982.
• Locomotion of animals, (Tertiary Level Biology), 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 Animal Biology Series), Oxford University Press, USA, 1999
• Exploring biomechanics: animals in motion, Nikei Saiensusha, ISBN 978-4-532-52017-5
• Hydraulic mechanisms in locomotion, In Body Cavities: Function and Phylogeny, pp. 187–198, Selected Symposia and Monographs U.Z.I., 8, Modena: Mucchi.
• Human Bones: A Scientific and Pictorial Investigation, with Aaron Diskin, Pi Press, 2004.
• Principles of Animal Locomotion, Princeton University Press, 2006
• Knochen! Was uns aufrecht hält - das Buch zum menschlichen Skelett, Spektrum Akademischer Verlag, 2006

### Papers

(This is merely a small sample from over 250 papers)

• 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, Zoological Journal of The Linnean Society, vol. 45, no. 305, 1964, pp. 169–190
• Estimates of speeds of dinosaurs, Nature, 1976;261:129–130. doi:10.1038/261129a0
• Bending of cylindrical animals with helical fibres in their skin or cuticle, J. Theor. Biol. 124, 1987, pp. 97–110.
• Tyrannosaurus on the run, Nature, 1996;379:121. doi:10.1038/379121a0
• Dinosaur biomechanics, Proc Biol Sci. 2006 August 7; 273(1596): pp. 1849–1855.
• Biomechanics: Stable Running, Current Biology, Volume 17, Issue 7, 3 April 2007, pp.R253-R255
• S. K. S. Thorpe, R. H. Crompton and R. McN. Alexander, Orangutans use compliant branches to lower the energetic cost of locomotion, Biology Letters, 2007
• A. Brandwood, A. S. Jayes, R. McN Alexander, Incidence of healed fracture in the skeletons of birds, molluscs and primates, Journal of Zoology, vol. 208, no. 1, 2009, pp. 55–62
• Biomechanics: Leaping lizards and dinosaurs, Nature, (2012), DOI: doi:10.1038/nature10797, 4 January 2012

## Film & TV work

• 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

[10]