Amphibians
Most people are familiar with amphibious vehicles that can travel both on land and in the water. In much the same way as these vehicles can function in either environment, amphibians are typically at home on land or in the water. Amphibians are members of the class Amphibia which includes frogs, toads, salamanders, and newts. There are an estimated 6,000 amphibian species worldwide to date.
Most amphibians have some mixture of aquatic and terrestrial adaptations. Most species of amphibians require water for reproductive purposes because their eggs, being without shells, easily dry out. Amphibians generally prefer to live in moist habitats partly because they need a damp environment to supplement their lung function. They use their skin to exchange gasses with the environment to assist their breathing. So, even those individuals who tend to prefer drier habitats spend a fair amount of time in relatively moist places in those environments.
Amphibians go through a metamorphic process where they go from being completely dependent on water to developing lungs and becoming able to live outside of the water.
When most people think of amphibians, they automatically think about frogs and toads, which are commonly referred to as anurans. And while there are differences between frogs and toads, which we will discuss briefly, toads are technically frogs. While not the only family of frogs on the planet, true frogs are members of the family Ranidae, which includes more than 400 species. In general, frogs typically have bulging eyes, long webbed back feet that are specially designed for jumping, and smooth skin. They also tend to lay their eggs in clumps. Toads, on the other hand, are members of the family, Bufonidae, which contains over 300 species. They typically have shorter, stubbier bodies, shorter hind legs, and tend to lay their eggs in long chains. Toads also have warty and dry skin, and parotid glands behind the eyes that secrete a toxin which is sometimes truly a poison and is sometimes just bad tasting (which causes a predatory animal to release it).
Most amphibians have some mixture of aquatic and terrestrial adaptations. Most species of amphibians require water for reproductive purposes because their eggs, being without shells, easily dry out. Amphibians generally prefer to live in moist habitats partly because they need a damp environment to supplement their lung function. They use their skin to exchange gasses with the environment to assist their breathing. So, even those individuals who tend to prefer drier habitats spend a fair amount of time in relatively moist places in those environments.
Amphibians go through a metamorphic process where they go from being completely dependent on water to developing lungs and becoming able to live outside of the water.
When most people think of amphibians, they automatically think about frogs and toads, which are commonly referred to as anurans. And while there are differences between frogs and toads, which we will discuss briefly, toads are technically frogs. While not the only family of frogs on the planet, true frogs are members of the family Ranidae, which includes more than 400 species. In general, frogs typically have bulging eyes, long webbed back feet that are specially designed for jumping, and smooth skin. They also tend to lay their eggs in clumps. Toads, on the other hand, are members of the family, Bufonidae, which contains over 300 species. They typically have shorter, stubbier bodies, shorter hind legs, and tend to lay their eggs in long chains. Toads also have warty and dry skin, and parotid glands behind the eyes that secrete a toxin which is sometimes truly a poison and is sometimes just bad tasting (which causes a predatory animal to release it).
Another type of frog you may encounter is the tree frog which belong to the family Hylidae. Tree frogs have very distinct toepads which function much like a suction cup to allow them to climb and stick to surfaces with relative ease. You can sometimes find them stuck to the window of your house eating bugs that are attracted to the light. If you look at the picture of the Cope's Gray Tree Frog (left), you will notice that the end of the toes are larger than the longer portion of the toe.
The frogs and toads, in general, are the vocal group of amphibians, which can be very useful in species identification. Anurans use their vocalizations to attract mates, and most vocalization takes place in the spring of the year.
The frogs and toads, in general, are the vocal group of amphibians, which can be very useful in species identification. Anurans use their vocalizations to attract mates, and most vocalization takes place in the spring of the year.
If you're interested in learning about anuran vocalization, you can read a paper I wrote several years ago that provides a great deal of introductory information by clicking here.
Below you'll find examples of some representative species of amphibians.
