English name: Chinese Edible Frog (aka “Chinese Bullfrog”, “Taiwanese Frog”)
Scientific name: Hoplobatrachus rugulosus (formerly known as Rana rugulosa)
Thai name: Kob Na, Kob nu
Description: To 16cm long. The largest frog in the Bangkok area, rivaled only by the Common Indian Toad. Heavy-bodied with distinct ridges in the dorsal skin. Body is olive-brown or gray. Legs are powerful, and feet are fully webbed. Underside is cream, sometimes with dark spotting.
Tadpoles are large, easily growing over 5cm. They are brown in color.
Call: A loud call that has been described as “auk auk”.
Similar Species: Asian Grass Frog is smaller, more slender, and often has a dorsal stripe.
Brackish Frog is smaller and has more slender legs
Common Indian Toad has shorter legs, a blunter and broader head, and has the characteristic “warts” of a toad rather than raised ridges.
Habitat: Found in still water bodies such as lakes, manmade ponds, ditches, rice paddies, and marshes. In Thailand I have found them in decorative fishponds, park ponds, and temple lakes. Almost always seen in or on the edge of water.
Place in the ecosystem: Eats insects, smaller frogs, and small rodents. The tadpoles feed on smaller tadpoles of other species. May be eaten by large birds, snakes, and monitors.
Danger to humans: No danger to humans.
Conservation status and threats: The Chinese Edible Frog is a Class II protected species in China and Taiwan, The IUCN Red List lists it as “Least Concern” due to their wide distribution and tolerance of a range of habitats. Though they are often collected for food, their populations appear to be able to handle the current level of exploitation. Personally, in Thailand I have only found them in manmade water bodies. The Chinese Edible Frog has been introduced to Malaysia and the Philippines.
Interesting facts: As their name should suggest, Chinese Edible Frogs are the most commonly eaten frog in Thailand. Containers of the frog for sale can be found in most outdoor Bangkok markets, and their presence in city ponds and temple lakes is likely due to the release of market-bought frogs.
The IUCN Red List: Hoplobatrachus rugulosus
Observations on Geographical Variation in the Asian frog, Hoplobatrachus rugulosus
A Field Guide to the Amphibians of Cambodia
Travellers’ Wildlife Guides: Thailand