Hyla japonica, commonly known as the Japanese tree frog, is a species of anuran native to Japan, China, and Korea. H. japonica is unique in its ability to withstand extreme cold, with some individuals showing cold resistance at temperatures as low as -30 °C for up to 120 days. H. japonica are not currently facing any notable risk of extinction and are classified by the IUCN as a species of "least concern". Notably, H. japonica have been sent to space in a study that explored the effect of microgravity on H. japonica. Hyla japonica is synonymous with Dryophytes japonicus. The Japanese tree frog lives in a variety of habitats such as wetlands, forests, rivers, and mountains. They are generally located near vegetation near water sources and forests. They are carnivores that prey on insects and spiders.Their average litter size is around 340-1500 eggs, and their lifespan is usually around six years. There is an estimated 100 million of these frogs in Japan, but the accuracy is limited due to difficulty in counting. Taxonomy Some authorities use the scientific name, Hyla japonica, in reference to the Japanese tree frog. The binomial name, Dryophytes japonicus, is also sometimes used. Studies have characterized the relationship between H. suweonensis and H. japonica. H. suweonensis is a closely related species to H. japonica. In general, H. suweonensis is smaller and more slender than H. japonica. The distance between nostril and upper lip (NL), distance between posterior corners of eyes (EPD), distance between semi-minor axis of the upper eye (LILe), angle between the two lines that connect the posterior corner of the eyes and ipsilateral nostrils (αEPD-N), and the angle between the two lines that connect the anterior corner of the eyes and the ipsilateral nostrils (αEAD-N) can all be used to differentiate between H. suweonensis and H. japonica. Description H. japonica are on average 32.81±0.96 mm in length. They have an average skull width of 12.02±0.36 mm and an average skull length of 9.38±0.14 mm. The dorsal body of H. japonica is green/brown and the ventral body is white. H. japonica is also characterized by a dark spot on the upper lip below the eye. Female H. japonica, on average, are larger in size compared to male H. japonica. H. japonica has a dark vocal sac. Abnormal coloration Some H. japonica are abnormally colored. Frogs observed in South Korea were found to be entirely blue,