Rana japonica
Silhouette: Sharp Photography, sharpphotography.co.uk · PhyloPic
In 3 days ~20% in a week ~30%
The Japanese brown frog (Rana japonica) is a species of frog in the family Ranidae, endemic to Japan. Its natural habitats are temperate grassland, rivers, swamps, irrigated land, and seasonally flooded agricultural land.
Defining characteristics include a slender, reddish-brown body with a long, narrow head. The average snout-vent length is 48 mm (0.157 ft) for males. Females are usually much larger than males, with lengths of about 54 mm (0.177 ft). Neither gender has a vocal sac, but males develop yellowish-brown nuptial pads and sing during mating season (which lasts from January to March). Songs consist of 10 to 20 notes.
R. japonica occurs in Honshu, Shikoku, and Kyushu in Japan to the southern region of China. Within Japan, it inhabits mostly hillsides and plains and is rarely seen in mountain ranges. More specifically, the brown frog resides in temperate grasslands, hillsides, plains, rivers, swamps, irrigated land, and seasonally flooded agricultural land.
By combining two types of recessive genes that cause frogs to become translucent, a breed of Rana japonica, popularly called "see-through frogs", was produced by... Wikipedia →
| # | Park | Country | Daily sighting probability |
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More parks will be added in future updates.
With luck
About 10% of wildlife watchers report a Japanese Brown Frog sighting in Tokyo on a given day, based on 47 verified sightings from GBIF citizen-science data. It is the 4th most-seen of the 11 amphibians we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
May to September
In those months about 10% of wildlife watchers report a Japanese Brown Frog in Tokyo on a given day, against under 5% in October to April, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Japanese Brown Frog sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
3rd of 3
Of the 3 cities where we can rate Japanese Brown Frog sightings, Tokyo ranks 3rd at about 10%. The best odds are in Sendai (Japan, about 30%) and Osaka (Japan, about 10%).
GBIF citizen-science records
It is estimated from how often the Japanese Brown Frog is recorded against all the amphibians logged in Tokyo (47 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
