Amphibians
Malabar Gliding Frog
Rhacophorus malabaricus · also called malabar gliding frog, malabar flying frog
The Malabar gliding frog is a slim, brilliant leaf-green tree frog from the forests of India’s Western Ghats, and it does two things that most frogs cannot. It parachutes between trees on four enormous webbed feet, covering ten metres or more in a controlled downward glide, and it raises its young inside a ball of whipped foam hung over a pool.
Overview
The Malabar gliding frog lives only in the Western Ghats of southwestern India, in moist forest and shaded secondary growth. Females reach 7–10 cm, males rather less. The frog is vivid green above, often with a pale belly and orange or red webbing between long, splayed toes.
Gliding on webbed feet
Its hands and feet are oversized and fully webbed. By spreading all four limbs, the frog turns each foot into a small parachute, and fringes of skin along the limbs add more area. Launched from a branch, it glides at a shallow angle across gaps of roughly 9–12 m, steering toward a landing on a trunk. Several unrelated frogs have evolved this trick; Wallace’s flying frog of Southeast Asia is the most famous.
The foam nest
During the monsoon, a female climbs onto vegetation overhanging a pool and releases fluid that she and attending males beat into a stiff foam ball with their hind legs. She lays her eggs inside it, safe from drying and from most predators. After a few days the foam softens and the tadpoles drop into the water below to finish developing.
Status
The Malabar gliding frog is currently Least Concern and locally common, but it depends completely on connected forest and clean breeding pools. Logging, conversion of forest to plantations, and development across the Western Ghats steadily erode both, and the frog vanishes where the forest is broken up.
Malabar Gliding Frog: common questions
Can the Malabar gliding frog really fly?
Not in the sense of powered flight, but it is a genuine glider. It cannot flap anything or gain height. What it can do is launch itself from a high branch and, by spreading its four large webbed feet and the skin fringes along its limbs, present enough surface area to the air to fall slowly and at a shallow angle rather than dropping straight down. In a single glide it can cover something like nine to twelve metres of horizontal distance while losing height, and it actively adjusts its posture to steer and to line up a landing on a trunk or branch. It is one of several unrelated frogs that have independently evolved this ability.
Why does it build a nest out of foam?
The foam nest solves two problems at once for a frog that breeds in warm, predator-rich pools during the monsoon. The whipped-up foam traps air and moisture, so the eggs inside stay damp even if the outside of the nest dries into a crust, and it is built on vegetation above the water rather than in it, which keeps the eggs away from fish, aquatic insects, and other egg-eaters in the pool. When the tadpoles are ready the foam breaks down and they slide out and drop into the water below to continue growing, having passed the most vulnerable stage in relative safety.
Where does the Malabar gliding frog live?
Only in the Western Ghats, the long chain of hills and mountains running down the southwestern side of India. Within that region it favours moist forest, both evergreen and deciduous, along with shaded secondary growth and the well-wooded edges of plantations, mostly at low to middle elevations where there are trees to glide among and temporary or permanent pools to breed over. The Western Ghats are a recognised biodiversity hotspot with an exceptional number of frog species found nowhere else, and this frog is one of the more conspicuous of them.
Is the Malabar gliding frog endangered?
It is currently listed as Least Concern, meaning it is still fairly widespread and locally common in suitable habitat. However, that status depends entirely on the forest. The frog needs connected tree cover to move and glide, and clean, still pools with overhanging branches to breed, and both are steadily reduced by logging, conversion of forest to tea, coffee, and other plantations, road building, and expanding settlements across the Western Ghats. Where forest is fragmented or pools are polluted the frog disappears, so its long-term outlook is tied to how much of the region's moist forest is kept intact.