Fejervarya cancrivora (Gravenhorst, 1829)
Family: Dicroglossidae Crab-eating Frog Status: Established The crab eating frog is a medium sized to large chunky frog with rugose skin. Coloration is variable but usually consists of a grey to brownish ground color with darker irregular blotches. A dorsal stripe may be present. The dorsal stripe can be narrow to broad and can vary in color from white to yellow to orange. There are prominent black bars on the lips. The bumps on the skin often form short longitudinal ridges. A second species of frog in the genus Fejervarya has been reported from Guam (Christy et al 2007). This frog, F. limnocharis, is very similar to F. cancrivora but differs in several ways. In general, adult F. cancrivora are a larger stockier frog. In adult male F. cancrivora the black markings on the throat are restricted to the sides with dusky coloration in between whereas in adult male F. limnocharis the black markings on the throat meet at midline. F. cancrivora also has more extensive webbing on the foot, generally extending to the last phalanx of the fourth toe. Despite intensive effort, and examining hundreds of specimens, the author has not found evidence of more than one species occurring on island (Wostl et al, 2016). The call is a rapid series of “eh-eh-eh” Biology: This frog is most often found in association with small permanent to semi-permanent bodies of water but can also be very common along small streams. It feeds on a wide variety of small invertebrates. It will also occasionally consume small vertebrates and on Guam, it has been observed eating a blind snakes, a Carlia, and a very large centipede in the genus Scolopendra (Pers. Obs). Unlike most other species of frog, the crab-eating frog is salt tolerant. It is common in brackish environments and has even been observed on small offshore karst islets. It seems to prefer breeding in small, marshy, semi-permanent puddles and ponds. On Guam males can be heard calling year round after it rains, but most breeding activity takes place during the wet season from June to October Distribution: Fejervarya cancrivora widely distributed throughout southern and eastern Asia. It was first detected in the Marianas on Guam in 2004 (Christy et al.2007). Since that time it has spread across the southern 2/3 of the island. Christy, M.T., C.S. Clark, D.E. Gee, D. Vice, D.S.Vice, M.P. Warner, C.L. Tyrell, G.H. Rodda, and J.A. Savidge. 2007. Recent Records of Alien Anurans on the Pacific Island of Guam. Pacific Science 61 (4) 469-483. Wostl, E., E. N. Smith and R. N. Reed. 2016. Origin and Identity of Fejervarya (Anura: Dicroglossidae) on Guam. Pacific Science 70(2): 233–241. DOI: https://doi.org/10.2984/70.2.9 |