Overview
The Black-webbed Tree Frog (Rhacophorus reinwardtii), also celebrated as Reinwardt’s Flying Frog, is an acrobatic and breathtaking arboreal amphibian native to the primary rainforest canopies of Sundaland. Clothed in a smooth, vibrant jade-green dorsal coat accented with luminous turquoise flanks, this canopy specialist is famed for its immense, fully webbed hands and feet featuring dramatic jet-black and electric-blue membranes. Utilizing these expansive webbed appendages like living parachutes, the frog executes controlled gliding flights between high jungle branches, descending safely across dizzying forest heights.
Biology and Physical Characteristics
The aerodynamic and arboreal morphology of Rhacophorus reinwardtii is a marvel of gliding mechanics. The frog features enlarged, spade-shaped discs on the tips of all digits that secrete sticky mucous fluids, providing immense capillary adhesion on slick tropical foliage. Connecting every finger and toe are colossal expanses of elastic interdigital webbing that can be spread wide into four concave airfoils; paired with lateral dermal skin flaps along the forearms and ankles, the frog can glide horizontally for distances exceeding 40 feet (12 m) while steering with subtle digit adjustments. Its dorsal emerald skin changes shade dynamically from bright yellow-green to dark moss-green for thermoregulation and camouflage.
Behavior and Ecology
Reinwardt’s flying frogs spend the vast majority of their lives high within the humid forest canopy, descending only during the monsoon wet season to reproduce. At night, males gather on vines and branches suspended over stagnant forest pools, inflating their single vocal sacs to produce soft, rolling chattering calls. During amplexus, the pair whips up a frothy, moisture-retaining foam nest attached to overhanging leaves, into which hundreds of pale eggs are deposited. As monsoon rains dissolve the outer crust of the foam nest, the newly hatched tadpoles wash into the pool below to complete their aquatic metamorphosis.
Conservation and Human Impact
Rhacophorus reinwardtii is classified as Near Threatened by the IUCN, with populations experiencing rapid declines due to widespread lowland deforestation for palm oil plantations, pulp production, and agricultural clearing across Java, Sumatra, and Borneo. Because it depends strictly on closed-canopy primary forests and unpolluted woodland pools, the species cannot persist in heavily disturbed monocultures. Conservation priorities focus on protecting contiguous tropical forest reserves and establishing canopy wildlife corridors across Sundaland.
Interesting Factoid
By spreading its immense jet-black and blue webbed feet, the black-webbed tree frog transforms into a living hang-glider, gliding more than 40 feet across the rainforest canopy with full steering control.
Last updated: October 2026