Frogs

FrogsLets learn about frogs!

By Gina Grant

Frogs are AmphibiansFrogs belong to a group of animals called amphibians. (am-fib-ee-anz). Amphibian means two-lives. Frogs begin their lives in the water as eggs and then tadpoles and when they are fully developed they live on land. Scientists believe that there are more than 4,000 different kinds of amphibians on Earth. Toads, newts, salamanders and caecilians (blind worms) are also members of the amphibian group.

Frogs are cold-bloodedFrogs are cold-blooded which means that their bodies are the same temperature as the air or water around them. When they are cold they will lay in the sun to warm up and when they get too warm they will go into the water to cool their bodies off.

Where do frogs live?

Frogs are found all over the world, and in every climate, except Antarctica.They can be found near any, and every, body of fresh water but prefer ponds, lakes, and marshes, because the water doesnt move very fast. Frogs cannot live in the sea or any salt water.Scientists have found frogs fossils that date back to the Jurassic period over 140 million years ago.

The Life-Cycle

Jelly covered Eggs

Frogs begin their lives as tadpoles that are hatched in the water from tiny jelly-covered eggs. The mother frog can lay thousands of eggs at one time. Imagine having thousands of brothers and sisters!

The jelly has an awful taste, which protects the eggs from predators until they are ready to hatch.

Tadpoles don't have eggs but frogs have eggs that turn into tadpoles then frogs. Frog eggs look look little jelly like sacks with little black dots in the middle.

Tadpoles Tadpoles are born with gills, just like a fish, so that they can breathe under water. They have a big head and a long tail. They definitely do not look like frogs, yet! Tadpoles have a tough life. Its a good thing they are fast swimmers to escape the many other creatures that hunt them in the ponds and lakes. They are a favorite food to fish and water beetles.

Metamorphosis

Metamorphosis is the change of shape during an animals life. During metamorphosis the tadpole will develop back legs first, then front legs. Around 6 weeks of life the mouth starts to widen. Sometime around 10 weeks the froglets, as it is now called, eyes start to bulge out and the tail begins to shrink and eventually disappear. When the lungs finish developing the froglet makes its way onto the land and, Ta-da! Its a frog!

Tadpole with legs to FrogletAfter four weeks, the tadpole grows two hind, or back, legs.The tadpole's gills move inside its body.

The tadpole's gills disappear and its lungs grow stronger.Two front legs grow where the gills were.

What do they eat?Frogs are carnivores, which means that they will eat meat.Small to medium sized frogs eat insects such as flies, mosquitoes, moths and dragonflies. Larger frogs will eat larger insects like grasshoppers and worms.Some large frogs will even eat small snakes, mice, baby turtles, and even other smaller frogs!

What about that tongue..?Frogs tongues are attached to the front of their mouths rather than at the back like humans. When a frog catches an insect it throws its sticky tongue out of its mouth and wraps it around its prey. The frogs tongue then snaps back and throws the food down its throat.

Characteristics

Frogs have very good eyesight. They bulge out the sides of their heads in order for the frog to see in nearly all directions.Frogs also have an amazing sense of hearing. You can often tell the difference between a male and female frog by the size of their eardrum, which can be seen behind their eyes. If the eardrum is smaller than the eye, the frog is a female. On males their eardrum is the same size as the eye.

Characteristics

Frogs have very powerful back legs and webbed feet that help them jump great distances, as well as, swim. Frogs even use their legs to dig, or burrow, underground for hibernating (although not all frogs hibernate!) Every different species of frog has his or her own look. They come in many colors, patterns and sizes.

Frogs(all different shapes, sizes and looks)

Frogs(all different shapes, sizes and looks)

Frogs(all different shapes, sizes and looks)

Predators

Frogs have many predators. Animal predators include birds, fish and reptiles.Some frogs are very good at camouflaging themselves so that they blend in with their environment, making it harder for their enemies to find them. Some frogs can change the colour of their skin depending on its surroundings.

Human DangerHumans have become a major danger for amphibians of all types. Water pollution is causing many deformities in frogs as well as poisoning them, and loss of habitat through the building of roads and houses. In some countries, frogs legs are considered a delicacy, which means that people love to eat them! Eew!

(Pictured is the native Maud Island Frog)

New Zealand Native FrogsNew Zealand has 4 native frog species.Frogs are declining everywhere in the world. More than most creatures, frogs are sensitive to disease, pollution, chemical poisons and environmental changes, as they absorb many things through their sensitive skin.New Zealands, Hamilton's frog (pictured) is the most critically endangered species, with less than 300 individuals remaining.