Frogs!

Class: Amphibia

Order: Anura (3,494 species)

Jump to a section!

What is an Amphibian? Natural History Frog Calls Declining Amphibians Deformed Frogs Frog Links

What is an Amphibian?

Amphibian means a being with a double life; living on land and water. Frogs spend at least some stage in their life cycle in water.

Natural History

Frogs are fascinating animals. They are cold-blooded, and use the surrounding environmental temperature to regulate their own body temperature. They generally prey on small arthropods, such as insects and spiders. Unlike toads, frogs have smooth skin, long limbs, and live in water. They can lay thousands of eggs, which are in the form of gelatinous masses. Frog tadpoles have a well developed tail, spherical bodies, short bodies, and eat mainly a vegetarian diet. The tadpole stage can last anywhere from a few days to a few years, depending on the species.

In general, females are larger than males. Adult frogs lose their tail, which makes jumping a lot easier. They have no neck, a short backbone, and a three-chambered heart. Their tongue is attached to the front of their mouth, and their eyes aid in swallowing. Their eyes and nostrils, which are found on top of the skull, allow them to hide their body in water and still see and breathe. Frogs have three main body types:

• aquatic (slender and streamlined body)
• terrestrial (shorter limbs, chunkier body)
• arboreal (sticky toe pads, loose belly skin, flatter body)

Frog Calls

Males posses a vocal sac and voice box, which they use to produce beautiful calls. Go out to a pond near you in the spring and listen for frog calls! Buy a tape of frog calls, and learn to distinguish the different species. Types of frog calls include:

• mating During the mating season, male frogs use a mating call to attract females.
• distress Males use a distress call usually when they are in the grasp of a predator.
• release A male frog will use a release call to let another male frog know that he has grasped him instead of a female.
• defense Males will use defense calls in territory disputes and other male-male encounters.

Declining Amphibians

Frogs are a declining species. One of the major threats to this species, as well as to all other species, is habitat destruction and alteration. As we all know by now, humans are altering the landscape at an alarming rate. What little tropical rainforests that are remaining are being lost to such destruction. We are clearing this land for timber, grazing land, and buildings. More than three-quarters of all frogs occur in tropical rainforests, which means that most frogs are being evicted from their homes with no place to go.

What makes amphibians susceptible to decline?

• over harvesting (for science classes, food, pet trade)
• very thin skin (both eggs and adults)
• dual habitat (pollutants on both land and water
• explosive breeders (so one event, like a drought, can wipe them out)
• they are not considered when managing land
• they are not easy to study (secretive, not easy to mark)
• little is known about their biology

What are the causes for amphibian decline?

• habitat destruction, alteration, and fragmentation
• acid rain
• pollution
• climate change
• over collection
• disease

Deformed Frogs

Frog deformities have been making news headlines for the past few years. The phenomena of frog deformities, which range from missing eyes to extra limbs, appears to be recent and growing. Many of the deformities have been found in the Midwest, and have scientists baffled. The cause of deformities could be due to climate change, water contaminated with heavy metals or pesticides, an amphibian parasite, or a combination of these things.

Frogs have very thin skin. They breathe through their skin, as well as through their lungs. They are most sensitive to their surroundings, which make them a good "indicator" species. What this means is that we should look to frogs for our own well being. If something is wrong in the environment, say a pollutant, chances are that frogs will be among the first affected.

Links to Frog Stuff

The Froggy Page
Frogland
Frog! Page
The Frog Store
Virtual Dissection Frog Kit: Frog Safe!