The origin of snake feeding


Snakes are renowned for their ability to engulf extremely large prey, and their highly flexible skulls and extremely wide gape are among the most striking adaptations found in vertebrates1,2,3,4,5. However, the evolutionary transition from the relatively inflexible lizard skull to the highly mobile snake skull remains poorly understood, as they appear to be fundamentally different and no obvious intermediate stages have been identified4,5. Here we present evidence that mosasaurs — large, extinct marine lizards related to snakes — represent a crucial intermediate stage. Mosasaurs, uniquely among lizards, possessed long, snake-like palatal teeth for holding prey. Also, although they retained the rigid upper jaws typical of lizards, they possessed highly flexible lower jaws that were not only morphologically similar to those of snakes, but also functionally similar. The highly flexible lower jaw is thus inferred to have evolved before the highly flexible upper jaw — in the macrophagous common ancestor of mosasaurs and snakes — for accommodating large prey. The mobile upper jaw evolved later — in snakes — for dragging prey into the oesophagus. Snakes also have more rigid braincases than lizards, and the partially fused meso- and metakinetic joints of mosasaurs are transitional between the loose joints of lizards and the rigid joints of snakes. Thus, intermediate morphologies in snake skull evolution should perhaps be sought not in small burrowing lizards, as commonly assumed, but in large marine forms.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: The evolution of the highly flexible snake jaw system, superimposed on a simplified cladogram of snake relationships.4,5,6,14
Figure 2: The lower jaw of a mosasaur, Platecarpus.


  1. 1

    Gans, C. The feeding mechanism of snakes and its possible evolution. Am. Zool. 1, 207–227 (1961).

    Article  Google Scholar 

  2. 2

    Greene, H. W. Dietary correlates of the origin and radiation of snakes. Am. Zool. 23, 431–441 (1983).

    Article  Google Scholar 

  3. 3

    Cundall, D. in Snakes: Ecology and Evolutionary Biology (eds Seigel, R. A., Collins, J. T. & Novak, S. S.) 106–140 (Macmillan, New York, 1987).

    Google Scholar 

  4. 4

    Rieppel, O. Areview of the origin of snakes. Evol. Biol. 22, 37–130 (1988).

    Article  Google Scholar 

  5. 5

    Kardong, K. V., Kiene, T. L. & Bels, V. Evolution of trophic systems in squamates. Neth. J. Zool. 47, 411–427 (1997).

    Google Scholar 

  6. 6

    Lee, M. S. Y. Convergent evolution and character correlation in burrowing reptiles: towards a resolution of squamate phylogeny. Biol. J. Linn. Soc. 65, 369–453 (1998).

    Article  Google Scholar 

  7. 7

    Caldwell, M. W. Squamate phylogeny and the relationships of snakes and mosasauroids. Zool. J. Linn. Soc. 125, 115–147 (1999).

    Article  Google Scholar 

  8. 8

    Russell, D. A. Systematics and morphology of American mosasaurs. Bull. Peabody Mus. Nat. Hist. 23, 1–237 (1967).

    Google Scholar 

  9. 9

    Bell, G. L. J in Ancient Marine Reptiles (eds Nicholls, E. L. & Callaway, J.) 293–332 (Academic, New York, 1997).

    Google Scholar 

  10. 10

    DeBraga, M. & Carroll, R. L. The origin of mosasaurs as a model of macroevolutionary patterns and processes. Evol. Biol. 27, 245–322 (1993).

    Article  Google Scholar 

  11. 11

    Lee, M. S. Y. & Caldwell, M. W. Anatomy and relationships of Pachyrhachis problematicus, a primitive snake with hindlimbs. Phil. Trans. R. Soc. Lond. B 353, 1521–1552 (1998).

    Article  Google Scholar 

  12. 12

    Estes, R., Frazzetta, T. H. & Williams, E. E. Studies on the fossil snake Dinilysia patagonica Woodward: Pt 1. Cranial morphology. Bull. Mus. Comp. Zool. Harv. 140, 25–74 (1970).

    Google Scholar 

  13. 13

    Underwood, G. Acontribution to the classification of snakes. Br. Mus. (Nat. Hist.) Publs 653, 1–179 (1967).

    Google Scholar 

  14. 14

    Cundall, D., Wallach, V. & Rossman, D. A. The systematic relationships of the snake genus Anomochilus. Zool. J. Linn. Soc. 109, 275–299 (1993).

    Article  Google Scholar 

  15. 15

    Greer, A. The Biology and Evolution of Australian Snakes (Surrey Beatty, Sydney, 1997).

    Google Scholar 

  16. 16

    Frazetta, T. H. The origin of amphikinesis in lizards: a problem in functional morphology and the evolution of adaptive systems. Evol. Biol. 20, 419–461 (1986).

    Google Scholar 

  17. 17

    Arnold, E. N. Cranial kinesis in lizards: variations, uses, and origins. Evol. Biol. 30, 323–357 (1998).

    Google Scholar 

  18. 18

    Callison, G. Intracranial mobility in Kansas mosasaurs. Paleontol. Contr. Univ. Kansas 26, 1–15 (1967).

    Google Scholar 

  19. 19

    Lingham-Soliar, T. Anatomy and functional morphology of the largest marine reptile known, Mosasaurus hoffmani (Mosasauridae, Reptilia) from the Upper Cretaceous, Upper Maastrichtian of The Netherlands. Phil. Trans. R. Soc. Lond. B 347, 155–180 (1995).

    ADS  Article  Google Scholar 

  20. 20

    Pregill, G. K., Gauthier, J. A. & Greene, H. W. The evolution of helodermatid squamates, with description of a new taxon and an overview of Varanoidea. Trans. San Diego Nat. Hist. Soc. 21, 167–202 (1986).

    Google Scholar 

  21. 21

    Frazzetta, TH. Studies on the fossil snake Dinilysia patagonica Woodward. II. Jaw machinery in the earliest snakes. Forma Functio 3, 205–221 (1970).

    Google Scholar 

  22. 22

    Cundall, D. Feeding behaviour in Cylindrophis and its bearing on the evolution of alethinophidian snakes. J. Zool. 237, 353–376 (1995).

    Article  Google Scholar 

  23. 23

    Boltt, R. E. & Ewer, R. F. The functional anatomy of the head of the puff adder, Bitis arietans (Merr.). J. Morphol. 114, 83–106 (1964).

    Article  Google Scholar 

  24. 24

    Kardong, K. V. Kinematics of swallowing in the yellow rat snake, Elaphe obsoleta quadrivittata : a reappraisal. Jap. J. Herpetol. 11, 96–109 (1986).

    Article  Google Scholar 

  25. 25

    Young, B. A. The comparative morphology of the intermandibular connective tissue in snakes (Reptillia: Squamata). Zool. Anz. 237, 59–84 (1998).

    Google Scholar 

  26. 26

    Iordansky, N. N. Jaw apparatus and feeding mechanics of Typhlops (Ophidia: Typhlopidae): a reconsideration. Russ. J. Herpetol. 4, 120–127 (1997).

    Google Scholar 

  27. 27

    Kauffman, E. G. & Kesling, R. V. An upper Cretaceous ammonite bitten by a mosasaur. Contr. Mus. Paleont. Univ. Michigan 15, 193–248 (1960).

    Google Scholar 

  28. 28

    Russell, D. A. Intracranial mobility in mosasaurs. Postilla 86, 1–19 (1964).

    Google Scholar 

  29. 29

    Gregory, J. T. Convergent evolution: the jaws of Hesperornis and the mosasaurs. Evolution 5, 345–354 (1951).

    Article  Google Scholar 

  30. 30

    Massare, J. A. Tooth morphology and prey preference of Mesozoic marine reptiles. J. Vert. Paleontol. 7, 121–137 (1987).

    Article  Google Scholar 

Download references


We thank V. Wallach, G. Underwood, K. Karding, N. Kley, J. Scanlon and A. Greer for discussion and comments on the manuscript; J. Rosado and J. Cadle (Museum of Comparative Zoology, Harvard University), O. Rieppel and A. Resatar (Field Museum of Natural History), C. Holton, T.Trombone and L. Ford (American Museum of Natural History), S. Chapman and C. McCarthy (British Museum of Natural History) and B.Purdy and K. de Queiroz (National Museum of Natural History, Smithsonian Institution) for access to materials under their care; and the Australian Research Council, Fulbright Foundation and NERC (Canada) for funding.

Author information



Rights and permissions

Reprints and Permissions

About this article

Cite this article

Lee, M., Bell, G. & Caldwell, M. The origin of snake feeding. Nature 400, 655–659 (1999).

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing