Hong Kong Cascade Frog

Description: A medium-sized frog, up to 6.5 cm in length, with a ground colour of grey or greyish brown, but in a few localities the specimens are dark, almost black. Dorsum with neat, round spots that re well separated from each other. Numerous granules on the back, flanks and legs. Has a very short, rounded snout. Eyes large. Underside pale, with dark vermiculations on the throat. Large, well-developed adhesive discs on all digits.

Habits and Habitat: Lives in swift-flowing hill and mountain streams, especially those with cascading water. Is found both at low and high altitudes. Its protective coloration and flat body enable it to remain undetected while perching on the slippery rock face, with water splashing over its body. Its large suction discs enable it to obtain a firm grip on the rock. Occasionally seen inside water catchments and water tunnels. Is nocturnal.

Diet: Adults feed on small flies, grasshoppers and insect larvae. Tadpoles graze on algae growing on rocks in streams.

Reproduction: Breeds in the rainy season. Females lay 12 to 60 cream-coloured eggs, which are glued to steep slippery rocks, in the shade of crevices and under rock ledges. The eggs are concealed from direct sunlight and are kept moist by water splashing over them. The tadpole has a large head and dark tail bands, and can reach 4 cm in total length. Has an enlarged sucker with which it clings to wet rock.

Distribution: Was once believed to be unique to Hong Kong, where it was first recorded in 1950 from Tai Mo Shan. Has recently been discovered near Daya Bay in southern Guangdong. Some researchers think it also occurs in Fujian Province (China). In Hong Kong can be found in many localities on Hong Kong Island and in the New Territories, where it is usually quite common. It seems unusual that it is absent from Lantau Island, which is Hong Kong's largest island.

Diagnostic features: Body flat, arrow-shaped, tapering towards the vent; broadest at the shoulders; large eyes; short, blunt, rounded snout; all digits with conspicuous adhesive discs.