Frogs and toads have evolved over millions of years and are presently widely distributed across the globe. They belong to the order Anura (Anura – an organism without a tail, in Greek). They are found in water as well as land, under the ground and on trees. They can dig, swim, climb trees, and glide. All these feats are possible owing to some special adaptations, which facilitate their survival in a range of habitats.
Though many a species of frogs and toads are terrestrial, some have taken to an arboreal lifestyle. Arboreal frogs spend most of their time in the canopy. They usually forage, feed and court on trees but descend to the ground to mate and lay eggs. Smaller species can be seen perched on low shrubs, only few feet off the ground whereas larger species perch several metres above the ground.
Arboreal species have bulb-like pads on their digits (i.e. fingers and toes) which enable them to maintain better grip on trees. They have long slender hind limbs and some species that glide have fully webbed feet which are used as ‘wings’ to maneuver mid-air.
Most arboreal frogs in India are drab or green in colour with beautiful patterns and colouration to attract mates. They sometimes change colour to blend in with the surrounding. They are mostly active at night and feed on insects like ants, beetles, crickets, mosquitoes, flies, as well as other smaller organisms. Arboreal frogs come in many sizes – they can be as small as 2cm and as large as 13 cm!
Here are a few images of arboreal frogs that are found in Karnataka:
Rhacophorus malabaricus : Also known as the Malabar Gliding Frog. One of the largest species of arboreal frogs, where males are smaller than females. R. malabaricus builds foams nests above stagnant pools of water. The tadpoles drop into this pool when they hatch. In the breeding season (during monsoon) one female is often pursued by more than one male (sometimes as many as 5-6), all vying for her attention.
Rhacophorus malabaricus : In one leap, the Malabar Gliding Frog can cover a distance which is more than 100 times its body size.
Dialated fingertips: Arboreal species such as this bush frog are able to leap from one twig to another owing to the bulb-like pads (also known as dilations).
Rhacophorus lateralis : Smaller in size as compared to R. malabaricus, R.lateralis is an endangered species of frog found only in some regions of the Western Ghats in South India. Their colouration is known to vary as a result their immediate habitat and at times, stress. The white streak on either side of the nostril, along the body is a distinguishing feature of this species.
Polypedates maculatus : Also known as Common India Tree Frog or Chunam Tree Frog. P. maculatus has an interesting behaviour where it covers itself with a layer of mucus and lipids to reduce loss of moisture when the weather gets dry. It sometimes turns pale when temperatures are high.
Croaking: The croaking of frogs in the tropics is regulated by the humidity in the air and is often enhanced just before or after rainfall. Most frogs have either one or two vocal sacs to amplify the sound of their call. The bush frog Raorchestes tuberohumerus seen croaking here was either trying to attract mates or defend territory.
Bluest eye: This frog is known as the Blue-eyed Bush Frog Raorchestes luteolus whose sighting can turn many frog lovers green! A beautiful golden-yellow colouration on the body and a blue rim around the eye make for the loveliest little bush frog.
Ramanella variegata : This narrow-mouthed frog is often found close to human habitation or perched on termite mounds, waiting for the termites to emerge. When threatened they lie flat on their belly and become immobile.
Kaloula taprobanica : Owing to the artistic red patterns on the body, this frog is also called the painted frog. It has a peculiar habit of bloating itself up like a balloon when threatened, perhaps in order to appear menacing to the predator!
Raorchestes chromasynchysi : Also called as the confusing coloured bush frog, has received its name because of the varied colouration that they possess
Raorchestes glandulosus :A beautiful tiny frog endemic to the Western Ghats, is seen with flashy colours on their thighs. Many bush frogs have such flash colours, which possibly could be used to communicate with other individuals.