A central role for venom in predation by Varanus komodoensis (Komodo Dragon) and the extinct giant Varanus (Megalania) priscus

Bryan G. Fry; Stephen Wroe; Wouter Teeuwisse; Matthias J. P. van Osch; Karen Moreno; Janette Ingle; Colin McHenry; Toni Ferrara; Phillip Clausen; Holger Scheib; Kelly L. Winter; Laura Greisman; Kim Roelants; Louise van der Weerd; Christofer J. Clemente; Eleni Giannakis; Wayne C. Hodgson; Sonja Luz; Paolo Martelli; Karthiyani Krishnasamy; Elazar Kochva; Hang Fai Kwok; Denis Scanlon; John Karas; Diane M. Citron; Ellie J. C. Goldstein; Judith E. Mcnaughtan; Janette A. Norman

doi:10.1073/pnas.0810883106

Edited by David B. Wake, University of California, Berkeley, CA, and approved April 16, 2009 (received for review October 28, 2008)

Abstract

The predatory ecology of Varanus komodoensis (Komodo Dragon) has been a subject of long-standing interest and considerable conjecture. Here, we investigate the roles and potential interplay between cranial mechanics, toxic bacteria, and venom. Our analyses point to the presence of a sophisticated combined-arsenal killing apparatus. We find that the lightweight skull is relatively poorly adapted to generate high bite forces but better adapted to resist high pulling loads. We reject the popular notion regarding toxic bacteria utilization. Instead, we demonstrate that the effects of deep wounds inflicted are potentiated through venom with toxic activities including anticoagulation and shock induction. Anatomical comparisons of V. komodoensis with V. (Megalania) priscus fossils suggest that the closely related extinct giant was the largest venomous animal to have ever lived.

Footnotes

¹To whom correspondence should be addressed. E-mail: bgf{at}unimelb.edu.au
Author contributions: B.G.F., S.W., and W.C.H. designed research; B.G.F., S.W., W.T., M.J.P.v.O., K.M., J.I., C.M., T.F., P.C., H.S., K.L.W., L.G., K.R., L.v.d.W., C.J.C., E.G., W.C.H., S.L., P.M., K.K., E.K., H.F.K., D.S., J.K., J.E.M., and J.A.N. performed research; B.G.F., S.W., W.T., M.J.P.v.O., and H.S. contributed new reagents/analytic tools; B.G.F., S.W., W.T., M.J.P.v.O., K.M., J.I., C.M., T.F., P.C., H.S., K.L.W., L.G., K.R., L.v.d.W., C.J.C., E.G., W.C.H., S.L., P.M., K.K., E.K., H.F.K., D.M.C., E.J.C.G., J.E.M., and J.A.N. analyzed data; and B.G.F., S.W., W.T., M.J.P.v.O., D.M.C., E.J.C.G., and J.A.N. wrote the paper.
↵²Present address: Fusion Antibodies Ltd., Belfast BT17 0QL, United Kingdom.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/cgi/content/full/0810883106/DCSupplemental.