Category Zoology

     The African bullfrog is one of the largest frogs in South Africa. It measures up to 24 centimetres, and may weigh over two kilogram’s. It has a chubby body with a broad head, and has olive-greenish coloured bumpy skin. This frog eats lots and lots of really big bugs, fish, and mice. It has tooth like projections on its lower jaw to restrain struggling prey, and will eat pretty much anything that will fit in its mouth or that it can overpower, including lizards, and other frogs. The males of this species are known to give nasty bites, so be careful around them!

 There are over 3500 species of frogs – and more are being discovered every year. Frogs have evolved in a wide range of sizes, shapes and colours that enable them to survive on land, water, and on trees. Some frogs are totally aquatic, and live only in the water. Some like the mole frog, cannot swim, and live only on land. Others live near ponds and streams, and are at home both on land, and water. But whether it is on land, water or on trees, frogs have mastered the art of survival through their camouflaging abilities, defensive mechanisms, and their adaptability.

  Usually, the female frog lays her eggs in water- often in underwater plants. She and the male then leave the eggs alone to develop on their own. In some species, one of the parents stays behind to watch over the eggs and care for the tadpoles.

            Some frogs build nests of different types for their eggs. An Australian frog builds a foam nest made by churning a mixture of water and mucus to trap air bubbles. Large circular nests of sand and gravel are constructed at the edge of streams by the Latin American tree frog. Some frogs are very good fathers. The males carry eggs from a moist place, such as the water in a cupped leaf, to a wetter place, like a pond. They may do this by placing the eggs on their back, in a pouch on their belly, or even in their mouth. Some males wait for the eggs to hatch, and then transport the tadpoles on their backs. Male poison arrow frogs take their duties as a parent very seriously. They guard the clutch of eggs devotedly, and carry out vital transportation duties too. In the case of the Darwin’s frog, the eggs develop inside the vocal pouch of the parent, and after hatching, emerge as young frogs, through the mouth!

   Generally speaking, frogs lay eggs in large numbers. However, this is not always the case. The number of eggs laid by a female frog depends on the way the eggs are fertilized, and an embryo is formed. It is this embryo that later develops into a baby frog or tadpole.

            Normally, the female lays her eggs in water, and the male frog sprays his cells over them. This is called external fertilization. A great number of eggs have to be laid for external fertilization, because many of the eggs may not get fertilized at all. However, in the case of some frog, the eggs are fertilized inside the female’s body. This increases the chance of fertilization actually taking place, and so, fewer eggs need to be produced.

            The number of eggs laid also reflects the amount of care that the parent frog gives. Those frogs that take more care of their young lay fewer eggs, as the babies have a greater chance of survival.

            Most frogs lay between 1000 to 2000 eggs at a time – the American toad lays 4000 to 8000 eggs in one clutch. On the other hand, the tailed frog lays only 28 to 50 eggs per clutch, while the Cuban frog lays only one egg at a time!

  To put it in a nutshell, frog lets are tadpoles that have almost lost their tails and that have developed legs. This happens when the tadpoles are around twelve weeks. Froglets still have a lot of growing to do before frogs. Between 12-16 weeks, the froglet totally absorbs its stubby tail, and leaves the water.

            Sometimes, the term froglet refers to a frog that skips the tadpole stage and emerges as a fully developed frog. The Namaqua rain frog is one such frog. The eggs are laid in an underground nest, and metamorphosis takes place inside the egg capsules with the young emerging as fully formed frog lets. The three toed Brazilian toadlet – which is not a toad at all but a frog – also have young ones that hatch directly from the egg.

   Metamorphosis is the change of shape during an animal’s life. In frogs, it refers to the change from the larval or tadpole stage, into an adult frog. Frogs and toads generally breed in the pond where they were born. The eggs – sometimes there are thousands of them – are laid in clumps called frog spawn. Hatching takes place about six days after fertilization, and the babies or larvae are called tadpoles.

            Tadpoles live like fish, and have a head, body, and tail. They live underwater, and breathe through gills. They feed on algae and tiny water plants. These lungs, and front legs too. They lose their tails, and begin to look like little frogs. By the time they are three months old, tadpoles have completed the process of metamorphosis. They are now adult frogs that are capable of breathing through their lungs, and living on land.