Buergeria japonica
Ryukyu Kajika Frog
family: Rhacophoridae
subfamily: Buergeriinae

© 2011 Mikhail F. Bagaturov (1 of 5)

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AmphibiaChina 中国两栖类.

Conservation Status (definitions)
IUCN (Red List) Status Least Concern (LC)
Other International Status None
National Status None
Regional Status None



View distribution map in BerkeleyMapper.

The body of this species is small and slender. The snout is thick and the canthus blunt. The hindlimbs have well developed webbing, but the forelimb has none. The mean snout to vent length for males is 28 mm (range 25-30) and for females it is 35 mm (range 27-37). There is a pair of slit-like vocal openings. In males, the nuptial pads are yellow. No dorsolateral fold exists, but the supratympanic fold is very prominent. The skin on the back is full of short tubercles and ridges.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Japan, Taiwan


View distribution map in BerkeleyMapper.
B. japonica is found in both Taiwan and Japan. In Japan, the species is specifically found on the Ryuku archipelago (or Nansei Islands). It can be found in a wide variety of habitats including, lowlands, near the seashore, and the forests in mountainous regions. The species usually lives on the ground or on rocks, and is seldomly found in trees.

Life History, Abundance, Activity, and Special Behaviors

Buergeria japonica has limited breeding sites. Tadpoles on this island were found in hot springs, and a new study (Komaki et al., Amphibia-Reptilia 2016) reports on the thermal tolerance of the species. The highest temperature of a pool occupied by tadpoles was 46.1 °C. Experiments show that this is very close to the critical thermal maximum of the species. Other frogs are known to inhabit hot springs but this is the highest temperature recorded in nature.

Possible reasons for amphibian decline

General habitat alteration and loss


Komaki, S., Lau, Q., Igawa, T. (2016). ''Living in a Japanese onsen: field observations and physiological measurements of hot spring amphibian tadpoles, Buergeria japonica.'' Amphibia-Reptilia, 37(3), 311-314. [link]

Maeda, N. and Matsui, M. (1990). Frogs and Toads of Japan, 2nd edition. Bun-Ichi Sogo Shuppan Co., Ltd., Tokyo, Japan.

Written by Ambika Sopory (shambika AT, UC Berkeley
First submitted 2000-10-16
Edited by Vance Vredenburg, updated by David Wake and Sierra Raby (2019-01-08)

Species Account Citation: AmphibiaWeb 2019 Buergeria japonica: Ryukyu Kajika Frog <> University of California, Berkeley, CA, USA. Accessed Aug 4, 2020.

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Citation: AmphibiaWeb. 2020. <> University of California, Berkeley, CA, USA. Accessed 4 Aug 2020.

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