The frog by nature is both damp and cold, its mouth is large and its belly will hold much; sits somewhat ascending, but waiting and loved to be kissed like in the story ‘The Frog Prince’.Frogs belong to the group of animals called amphibians.
Amphibian means both kinds of live. Normally, most types of frogs begin their lives in the water as eggs, and then hatchlings are called tadpoles and when they are fully metamorphosed into frogs they live on land although some frogs, known as direct developing ones, are born as full frogs.
Frogs can be found everywhere in the world except Antarctica. However, the highest diversity of frogs is found in tropics.So, when it comes to Sri Lanka, it harvests a rich amphibian fauna consists of nearly 120 varieties of frogs.
Never adopted but well adapted
Frogs are cold-blooded vertebrates like snakes. But they have a moist granular skin while snakes have dry, scaly skin. Their skin is capable of absorbing water into their body tissues so they can survive without drinking water. Although you hear many frog calls around the places that have water like ponds and streams, some frogs will never enter the water.
Some live on land and go to the water only to mate. Then, there are some kinds that live in trees. These frogs have tiny sticky adhesive discs on their fingers and toes to facilitate them cling to the tree trunk and branches as they climb. Frogs who associates with water have webbed feet for swimming. Some frogs live as burrowers which have short hind legs and cannot hop. Frogs that live in temperate countries hibernate during winter, either in burrows or buried in muddy bottoms of ponds.
The male frogs are the ones who make calls. Different species make different types of vocal patterns. Males are the ones that have the loud voice. Male frogs sing (grunts, croaks) to attract their females for mating. Some frogs even have a vocal sac which fills with air and swells up like a balloon. It amplifies the sound and makes it much louder. Some males use these vocal calls as a territorial call to indicate other males of the same species that this territory belongs to them.
Snatching a prey
Frogs are much active at night. They sit silently and steadily, waiting for their prey to come into their range. Then…when the prey is at their vicinity their sticky tongues very quickly snatch the prey. When it catches the prey, it flips out its tongue rapidly, gets the prey and retracts its tongue and swallows it in one piece. Frogs don’t have much to do with their teeth. They have a ridge of very small teeth along the edge of the upper jaw. These are called Maxillary Teeth. They also have another type of teeth called Vomerine Teeth on the roof of their mouth.
Frogs in love
You may have noticed that one large frog carries a small frog on its back. You might have thought it’s giving a free-ride to the small one. But of course not! Once the male frog attracts a female to mate, it will sit on the female’s back and hold onto it. It is called an amplex. As the eggs are released into the water, the male will release sperm over them to fertilize them and then both will leave. So, after weeks later, tadpoles come out when eggs get hatched. Finally, they metamorphose into complete adult form of frogs. And the cycle continues in the same way.
Writer is currently working as a Zoology (Graduate) researcher at Peradeniya University