ACADEMIA JOURNAL OF BIOLOGY 2019, 41(4): 25–30 DOI: 10.15625/2615-9023/v41n4.14581 25 A GIANT CROCODILE SKULL FROM CAN THO, NAMED “DAU SAU”, REPRESENTS THE LARGEST KNOWN SALTWATER CROCODILE (Crocodylus porosus) EVER REPORTED FROM VIETNAM Thomas Ziegler 1,2 , Nguyen Thien Tao 3,* , Nguyen Trung Minh 3 , Rainier Manalo 4 , Arvin Diesmos 5 , Charlie Manolis 6 1 AG Zoologischer Garten Köln, Riehler Strasse 173, D-50735 Cologne, Germany 2 Institute of Zoology, University of Cologne, Zülpicher Strasse 47b, D-50674 Cologne, Germany 3 Vietnam National Museum of Nature, VAST, Vietnam 4 Crocodylus Porosus Philippines Inc., Pag-asa, Kapalong, Davao Del Norte, Philippines 5 Philippine National Museum of Natural History, T.F. Valencia Circle, Rizal Park, T.M. Kalaw Avenue, Ermita, 1000 Manila, Philippines 6 Wildlife Management International, PO Box 530, Karama, NT 0813, Australia Received 4 November 2019, accepted 8 December 2019 ABSTRACT We report on a large crocodile skull recovered from a river bank in August 2010 near Dau Sau Bridge, in An Binh, Ninh Kieu District, Can Tho Province, in southern Vietnam. As the skull from Can Tho, named “Dau Sau” herein, is now deposited in the Vietnam National Museum of Nature, Ha Noi, we reinvestigated the circumstances surrounding its discovery and provide exact measurements. Skull length (dorsal mid-point) is 70.7 cm. The morphological features confirm it is from a Saltwater crocodile (Crocodylus porosus), and not a Siamese crocodile (C. siamensis), which historically also occurred throughout the Mekong Delta of Vietnam. Skull measurements are compared with those of other large C. porosus skulls for which reliable estimates of total length are available. We also provide measurements of the prepared skull of “Lolong” (69.8 cm), a 6.17 m long C. porosus captured in the Philippines in 2011. On the basis of known skull length:total length ratios the crocodile from Can Tho is estimated to be 6.3-6.8 m long. The skull of Dau Sau is likely to have been buried for at least 100 years. We discuss the origin of the local name Dau Sau, which has traditional and cultural significance, and provide historical reports of crocodiles in the area. Dau Sau is smaller than the largest known C. porosus skull (76 cm), but is the largest ever reported from Vietnam, and one of the largest C. porosus known. Keywords: Crocodylidae, Mekong delta, morphology, size, “Lolong”, Philippines. Citation: Ziegler T., Nguyen Thien Tao, Nguyen Trung Minh, Manalo R., Diesmos A., Manolis C., 2019. A giant crocodile skull from Can Tho, named “Dau Sau”, represents the largest known saltwater crocodile (Crocodylus porosus) ever reported from Vietnam. Academia Journal of Biology, 41(4): 25–30. https://doi.org/10.15625/2615-9023/v41n4.14581. *Corresponding author email: taont@vnmn.vast.vn ©2019 Vietnam Academy of Science and Technology (VAST)