Teaching Unit

                                                                                       Frogs

                                4th Grade

Frog Facts:

Frogs are amphibians. Amphibians are frogs, toads, salamanders, and caecilians( worm-like amphibians). The word means double life--many species spend part of their life in water and land environments. Because their skin lacks a shell, scales or outer drier covering, most amphibians live in wet or damp situations to prevent dehydration.

Amphibians are cold-blooded vertebrate animals (animals with a backbone) . They differ from reptiles in that they lack scales and generally return to water to breed.

Difference Between Frogs and Toads:

Characteristics of Frogs:                                     

• two bulging eyes
• strong, long, webbed hind feet that are adapted for leaping and swimming
• smooth or slimy skin (generally, frogs tend to like moister environments)
• frogs tend to lay eggs in clusters
• teeth around upper jaw

Characteristics of Toads:

• stubby bodies with short hind legs (for walking instead of hopping)
• warty and dry skin (usually preferring dryer climates)
•  poison glands behind the eyes
• The chest cartilage of toads is different also
• toads tend to lay eggs in long chains. (There are some toads ( Nectophrynoides), however, that bear live young!)
• no teeth

Life Cycle Of A Frog:

                                                                Frog eggs                   Toad eggs   

1st: Egg-

Tiny frog eggs are laid in masses in the water by a female frog. The eggs hatch into tadpoles

§§2nd: Tadpole - (also called the polliwog)               

This stage hatches from the egg. The tadpole spends its time swimming in the water, eating and growing. Tadpoles breathe using gills and have a tail.

3rd: Tadpole with legs -                                       

In this stage the tadpole sprouts legs (and then arms), has a longer body, and has a more distinct head. It still breathes using gills and has a tail.

§4th: Froglet -                                

In this stage, the almost mature frog breathes with lungs and still has some of its tail

§

 

 

 

§5th: Adult -                                   

The adult frog breathes with lungs and has no tail (it has been absorbed by the body).

 

 

 

Picture Of A Frog's Life Cycle

Frog Tracks

Look for these frog tracks near wet marshes, ponds and streams wherever frogs are common!

Frog Teeth

Frogs have teeth, but not like this silly picture. They have a ridge of very small cone teeth around the upper edge of the jaw. They don't have anything that could be called teeth on their lower jaw, so they usually swallow their food whole. The so-called "teeth" are mainly used to hold the prey and keep it in place till they can get a good grip on it and squash their eyeballs down to swallow their meal. Ewww sounds gross!

What Do Frogs Eat?:

Adult frogs will seldom eat dead or still objects--they are attracted to moving things such as:

•  live earthworms

•  insects

•  spiders

•  crickets

•  fruit flies or moths

Frog Enemies:

Frogs have to watch out for all kinds of enemies in the wild. Animals that eat frogs are: 

• snakes

• lizards

• birds

• and various small animals like hedgehogs.

• and maybe other hungry frogs

Frog Protection:

Many frogs rely on the art of camouflage to avoid getting spotted by predators.
Some blend with their backgrounds, while others even change colors to match the backgrounds!
Can you see the frog in this picture? It is really hard. He is doing a good job of camouflaging himself.

Pictures of Frogs:

Green Treefrog                                                 Bullfrog                                             Carpenter Frog

American Toad                                           Squirrel Treefrog                                   Pinewoods Treefrog