Oriental fire-bellied toad

Species of amphibian

The Oriental fire bellied toad (Bombina orientalis) is a small semiaquatic frog species found in northeastern Asia, where they primarily dwell in slow moving bodies of water and temperate forests. Quite common throughout much of their range, these frogs have mild toxins that can be excreted through their skin, with their vibrant underbellies serving as a warning of this. While not a true toad, their green and black skin is covered in small tubercles, giving them a toadlike appearance. Their sounds, mainly produced by males during the mating season, are very unlike those of other frogs. While their population is in decline, their numbers are still high overall, with the International Union for Conservation of Nature (IUCN) rating them as a least concern species. They are commonly kept as pets in land and water vivaria, as a relatively easy to care for species. They are also frequently used in scientific research, with their behavior, vocalizations, and learning skills all moderately studied.

According to the American Museum of Natural History, the red bellied toad, Chinese bell toad, Oriental bell toad, eastern fire bellied toad, and Korean fire bellied toad are all common names that have been used to describe the species at one point or another.

The Oriental fire bellied toad was first described by George Albert Boulenger as Bombinator orientalis, who placed it within the same genus as the European fire bellied toad and the Apennine yellow bellied toad, noting their many similarities. He considered it an "intermediate" between the latter two species, although he thought it was closer to the Apennine yellow bellied toad overall. His research was based on 19 specimens housed in the British Museum. The three species have been moved into the genus Bombina in 1907 by Leonhard Stejneger. The toad was later divided into two subspecies in 1972, B. o. practicola and B. o. silvatica, with the former being more aquatic and the latter more terrestrial, although newer research has found them to display few genetic differences, despite some physical ones. These findings support their classification as a monotypic species, albeit one with multiple morphs that may have diverged rather recently. A population in Beijing, despite having existed for less than a hundred years, has shown signs of evolution at a molecular level, displaying genetic uniqueness from the original population. While genetic diversity is somewhat low, it is still high enough that the Beijing toads may continue to survive. In the late Quaternary, seismic activity at the Yilan–Yitong fault zone is believed to have split the toad into two subpopulations in its native range, with the much smaller western one having low genetic diversity. In more recent times, gene flow has begun to occur between the two.

Oriental fire bellied toads can be bright, grayish, or brownish green, with black mottling on their dorsal regions. Like other Bombina species, B. orientalis has a brightly colored ventral region, which can be yellow, red, or orange red, mottled with dark spots. The finger and toe tips are usually red. Although it is typically referred to as a toad, the fire bellied toad is not a true toad. They can reach a length of about , weighing about Males and females can be told apart by the males' nuptial pads on their first and second fingers.) and northeastern China, and possibly southern Japan, specifically Tsushima Strait, although the latter is very likely erroneous, as a team of Japanese researchers in the later half of the 20th century was unable to locate any. There is also a somewhat genetically distinct population in Beijing that was introduced from Yantai in Shandong in 1927 by Mr. Liu Cheng chao. About 200 were released into wetland habitats, where they later bred. There have been no other reports of such occurrences in the United States, and there are no well established escaped populations. They are semiaquatic, generally dwelling in slow moving streams or ponds. When out of the water, they can often be found in coniferous and broadleaved forests.

Bombina orientalis are one of the most plentiful amphibians in their native lands, particularly the central part of their range. The toads are diurnal (active during the day), and studies have found that while they can acquire some from their diet, Oriental fire bellied toads rely partly on sunlight to obtain adequate levels of vitamin D3.

As larvae, Oriental fire bellied toads consume algae, fungi, detritus, plants and protozoans. As adults, their diet consists of terrestrial invertebrates, including worms, molluscs and insects. Oriental fire bellied toads are incapable of extending their tongues to catch prey, but must instead leap at their target. Females have been found to be quickly attracted to the advertisement call, but not the release call, displaying an ability to differentiate between them. Males typically ignore the advertisement calls, but will approach the source of release calls. In both cases, visual stimuli are also necessary to trigger a reaction. In addition to their lighter sounds, they can also produce a croaking noise.

Oriental fire bellied toads are rapid learners, especially compared to other frogs. In an experiment, slightly dehydrated toads were found able solve both simple and more complex mazes using water as a reinforcement, unlike other types of frogs (members of Rana, Bufo, and Hyla simply either did not try or leapt around aimlessly). In a simple T maze, with their target on the right side, 80% had navigated their way successfully in only three days, with 100% having finished after four days. The left side proved more challenging, with 80% finished in three days, but the rest not done until day eight.

As common amphibians, B. orientalis make excellent model organisms for studying the effects of pollution and toxic chemicals on local environments. Studies involving them having demonstrated the harmful effects of carbaryl (which include bent trunks, thicker set bodies, bent tails, and ventral blistering) and nonylphenol (which significantly decreased overall survival rates) on amphibian embryonic development.

The oriental fire bellied toad was listed as least concern species by the International Union for Conservation of Nature with little threat of extinction, although the population is declining, but not at a significant rate. They occur in many protected areas in China and the Koreas, as well as six Russian nature reserves. The population in the Russian part of their range may be more threatened than others. Dangers include pollution, urbanization, and use in traditional Chinese medicine.

Bombina orientalis are relatively easy to care for in captivity, requiring little in the way of specialized lighting or heating and readily consuming feeder insects or small feeder fish. Handling can require caution, as although harmless to the skin, the mucus can cause discomfort to the mouth and eyes, however captive individuals generally are less toxic. The toxin does not pose a significant threat to human health. In captivity, Oriental fire bellied toads often live for around 12 years, but in some cases can live up to 30.