Amphibians and Reptiles in Kikuchi Gorge
Most amphibians such as frogs and salamanders begin their lives in or near water, grow up and spend their adulthood in damp forests, and return to the water to lay their eggs. Areas such as Kikuchi Gorge, where the two environments merge, are ideal habitats for them and also attract reptiles, some of which feed on amphibians. These are some of the common amphibians and reptiles that inhabit the gorge.
The Hynobius oyamai salamander (chikushibuchi sanshouo) dwells on the forest floor and in clear streams throughout the gorge. It hides under rocks during the day and comes out only at night to hunt for woodlice and other insects to feed on, making sightings rare. Adult salamanders are between 11 and 15 centimeters long and bluish-gray. The Hynobius oyamai lays its eggs in pouches underneath rocks in the water from April to May, and in summer its younglings can often be seen swimming in streams and pools where they hunt for aquatic insects. In autumn, the adolescent salamanders move to the forest, altering their diet. The Hynobius oyamai is thought to exist only in northeastern Kyushu.
The dark-brown tago frog (tagogaeru; Rana tagoi) is the most common frog in Kikuchi Gorge. About 5 centimeters long, it is usually seen near small pools and puddles by the river. The frog lays its eggs in underground streams because its pearly white tadpoles require complete darkness to grow, feeding solely on the nutrients in the egg from which they emerge. They develop a pigment gradually before rising from the water as adolescents. Another frequent sight in the gorge is the local species of common toad (Nihon hikigaeru; Bufo japonicus), which can grow up to 18 centimeters long, making it the largest frog in Japan. Its black tadpoles can be spotted swimming in pools along the gorge’s walking paths. Less easy to find is the kajika frog (kajikagaeru; Buergeria buergeri), which is noted for its melodic cry. This song, used by male frogs to call females during mating season from April to July, is cited as a symbol of early summer in Japanese poetry.
Two noteworthy residents of the damp forest floor, which is covered with decomposing fallen leaves, are the akahara fire belly newt (akaharaimori; Cynops pyrrhogaster) and the takachiho odd-scaled snake (takachihohebi; Achalinus spinalis). The former, a small lizard-like salamander often seen lounging in pools and puddles near the river, is distinguished by its red and black belly. The exact color pattern is unique to each individual and remains almost unchanged throughout the newt’s lifespan, which can be up to 25 years. Though the red hue is a sign of poison, this animal’s toxin is generally not dangerous to humans. The dark-gray odd-scaled snake, on the other hand, has no poison and tends to stay out of sight, moving about mainly at night in search of earthworms, its preferred food.