Mindanao Water Monitor (Varanus cumingi) Family: Monitor Lizards (Varanidae) Orden: Squamates or Scaly Reptiles (Squamata)

Size:  Usually 100-130 cm, maximum 150 cm. Weight 800-1400 g, max. 2500 g. Distribution:  Southern Philippines (Basilan, Bohol, Leyte, Mindanao, Samar, and other nearby islands). Habitat:  Mangroves, along rivers and in cultivated areas. Whether the Mindanao Water Monitor is found also farther from the coast and at higher altitudes, is not known with certainty. Food:  Mainly smaller animals, such as worms, insects, and other invertebrates, but also fish, amphibians, reptiles, mammals, and possibly birds. Reproduction:  Probably not seasonal, due to the tropical range of the species. A highly pregnant female was found in November with 10 eggs. Most of what is known about the lizard is based on observations of captive specimens. The initial mating ritual begins on land, but the mating itself has only been observed under water and takes place about 4 weeks before the eggs are laid. Up to 5 days before the eggs are laid, the female begins searching for a suitable place for a nest. As many as three clutches are laid annually in intervals of 3½-5 months. The eggs measure 3.5-7.4 cm when they are laid and weigh 56g on average. During the incubation, the eggs are attended by the female, who also guards them against predators. It regulates the nest, so the incubation temperature initially is 27-28°C and later 28-30°C. The hatching period lasts 190-220 days. The youngs measure 28-31 cm when they hatch and weigh 26-42g. Atypically for monitor lizards, they differ from the adults by having darker and more obscure colours. The brighter colours develope as they grow older. In other monitor lizard species, the youngs most often have brighter pattern and colours than adults. Activity and behaviour:  Diurnal. As in other, closely related species, ritual combat has been observed, both between males and females, and females in between. During these fights, the animals force each other up on hindlegs, belly against belly. The fact that the fights are ritual means that they are not fought to the death of one of the animals. This behaviour is believed to influence rank or territories. Longevity:  Compared with other reptiles, monitor lizards grow relatively old, and the Mindanao Water Monitor will probably live to be 10-20 years, quite possibly even older. Variation:  The Mindanao Monitor Lizard occurs in two different subspecies: V. c. cumingi from Mindanao and Camiguin, and V. c. samarensis from Bohol, Leyte and Samar. The former has extensive, yellow pattern on head and body, while the latter has a darker, almost grey head and far less extensive yellow pattern on the back. Status for the populations on the remaining islands within the range of the species is unresolved. Status:  International trade in this species is regulated by CITES (Appendix II). Notes:  The Mindanao Water Monitor was until recently considered a subspecies (race) of the Asian Water Monitor (Varanus salvator), as was several other former subspecies, which are now also regarded as separate species (see Koch, Auliya, Schmitz, Kuch & Böhme 2007). It can be distinguished from the Asian Water Monitor by the more extensive yellow pattern on head and body. References: Alcala, A.C. 1976. Philippine land vertebrates: field biology. (A college textbook). New Day Publishers, Quezon City. 167 pp. Alcala, A.C. 1986. Guide to Philippine flora and fauna. Vol. 10. Amphibians and reptiles. Natural Resources Management Center, Ministry of Natural Resources & University of the Philippines, Manila. 195 pp. Bennett, D. 1998. Monitor lizards. Natural history, biology & husbandry. Edition Chimaira, Frankfurt am Main. 352 pp. (2nd revised and expanded edition of "A little book of monitor lizards". Edited by T. Wilms & B. Bartholemew). Böhme, W. 2003. Checklist of the living monitor lizards of the world (family Varanidae). Zoologische Verhandelingen (Leiden) 341: 1-43. Brown, W.C.; Alcala, A.C. 1970. The zoogeography of the herpetofauna of the Philippine Islands, a fringing archipelago. Proceedings of the California Academy of Sciences (Ser. 4) 38(6): 105-130. Carey, J.R.; Judge, D.S. 2000. Longevity records: life spans of mammals, birds, amphibians, reptiles, and fish. Odense University Press, Odense. 241 pp. Eidenmuller, B. & Philippen, H.D. 2008. Varanoid lizards. (Terralog vol. 6). Edition Chimaira, Frankfurt am Main / Rodgau. 148 pp. Eidenmüller, B. 2007. Monitor lizards: natural history, captive care, breeding. Chimaira, Frankfurt am Main. 176 pp. Gaulke, M. 1991. Systematic relationships of the Philippine water monitors as compared with Varanus s. salvator, with a discussion of dispersal routes. Mertensiella 2: 154-167. Gaulke, M. 1992. Distribution, population density, and exploitation of the water monitor (Varanus salvator) in the Philippines. Hamadryad 17: 21-27. Horn, H.G. 1994. Der Ritualkampf von Varanus salvator cumingi. Herpetofauna (Weinstadt) 16(92): 27-30. Koch, A.; Auliya, M.; Schmitz, A.; Kuch, U.; Böhme, W. 2007. Morphological studies on the systematics of South East Asian water monitors (Varanus salvator complex): nominotypic populations and taxonomic overview. Mertensiella 16: 109-180. Pianka, E.R.; King, D.R.; King, R.A. (eds.). 2004. Varanoid lizards of the world. Indiana University Press, Bloomington. 588 pp. Reptile Database. www.reptile-database.org Rese, R. 1986. Varanus salvator cumingi Martin, 1838. Sauria (Berlin) 8(3): 28. Wicker, R.; Gaulke, M.; Horn, H.G. 1999. Contributions to the biology, keeping and breeding of the Mindanao water monitor (Varanus s. cummingi). Mertensiella 11: 213-223. Text & layout: Rune Midtgaard

Gallery Home The conspicuous yellow pattern on head and body is characteristic for animals from Mindanao. Those from other islands have more obscure pattern and colours. © Rune Midtgaard.