Skip to content

Bornean Flat-headed Frog

Barbourula kalimantanensis


The Endangered Bornean flat-headed frog is the world’s only known lungless frog, and respires entirely through its skin!

Before 2008, this species was known from only two specimens collected 20 years apart. Multiple directed surveys failed to record any further populations of the frog until it was rediscovered in 2008. Since this rediscovery, several more individuals have been recorded in areas outside of where the species was originally thought to occur.

The Bornean flat-headed frog is one of only two species in its genus, and its sister species is found in the Philippines. Together, these two frogs diverged from all other living amphibians around 65 million years ago. That is around the same time that dinosaurs went extinct!

The Bornean flat-headed frog is threatened by habitat destruction due to illegal gold mining, which has also led to the siltation and pollution of the rivers in which it lives. The species is not currently known from any protected areas, and the conservation of habitat upstream from the distribution of the species is important.

  • Order: Anura
  • Family: Bombinatoridae
  • Population: Extremely rare
  • Trend: decreasing
  • Size: 66-77mm

EDGE Score

EDGE Score: 6.23 (?)
ED Score: 62.75 (?)
GE / IUCN Red List (?)
Not Evaluated Data Deficient Least Concern Near Threatened Vulnerable Endangered Critically Endangered Extinct in the Wild Extinct


This species is known only from West Kalimantan in Indonesian Borneo, where it is presently known only from two localities in the middle of the Kapuas River basin

Habitat and Ecology

The species live in clear rocky rivers, under large rocks in midstream within tropical moist forest. Its morphology suggests it is fully aquatic and dependent on clear water with high oxygen content. Breeding ecology is unknown.

Find out more

This wordcloud illustrates the threats facing this species. The size of each word indicates the extent of a species range that is affected by that threat (larger size means a greater area is affected). The colour of the word indicates how much that threat impacts the species (darker shades of red mean the threat is more severe).

Mining Logging Industry Agriculture

Threat wordcloud key:

Small area affected
Large area affected
Least severe
Most severe
Severity unknown
Source: The IUCN List of Threatened Species. Version 2017.1.
Available at: