Most amphibians undergo a unique change from larvae to adults, called metamorphosis. All amphibians are ectotherms what used to be called "cold-blooded" , a trait they share with invertebrates, fish, and reptiles.
Most amphibians have thin skin that is very permeable allowing liquids and gases to pass through it easily. This is important for two reasons. First, it means that their skin helps them breathe, since oxygen passes easily through it. Second, it means that amphibians lose a lot of water through their skin.
This is why most amphibians are found in moist or humid environments, where they can re-load their water reserves. The word amphibian comes from the Greek word amphibios , meaning "a being with a double life. While dual residence is the rule for most amphibians, some species are strictly aquatic water-dwelling and some are strictly terrestrial land-dwelling. More accurately, amphibians' "double life" refers to two distinct life stages -- a larval stage and an adult stage.
Most amphibians lay eggs, which hatch into larvae and undergo an amazing transformation or metamorphosis as they move from larval to adult stages. For instance, tadpoles the larval stage of frogs have gills and a tail -- features that enable them to live underwater. During metamorphosis, tadpoles lose their gills and develop lungs so they can breathe out of water.
At the same time, they begin to grow limbs and lose their tails. The end result: adult frogs who spend much of their time on land. Amphibians, like reptiles, are ectotherms. Imagine for a moment, that you're touching a frog's skin.
How would it feel? Now imagine the back of an alligator, with its scaly back. Which animal would have the smooth back and which would have the rough back? It's all about the skin: First — Amphibian skin is smooth and moist. They do not have that thick, scaly skin that is a trait of all reptiles. Amphibians do not have scales, feathers, or even hair like other animals. Since it does not have that protective covering, an amphibian's skin can easily dry out.
Second — Since their skin is exposed, they can breathe or exchange gas oxygen through their skin they can still breathe through their lungs too. Third — To keep the skin moist, amphibians prefer moist, humid, and wet homes or habitats. They will also secrete mucus through their skin to help protect the skin and keep it moist. The word amphibian comes from two Greek words amphis and bios which together means double life. In some species, like many salamanders, they rely on chemical cues called pheromones for mating.
Yes, a lot of amphibians have teeth. However, they do not have the same kind of teeth that we have. They have what are called vomerine teeth that are only located on the upper jaw and are only in the front part of the mouth.
These teeth are used to hold onto prey and not used to actually chew or tear apart prey. Amphibians swallow their prey whole, so they do not need teeth for chewing. They are called vomerine because they are found in the facial bone called the vomer. Amphibians will pretty much eat anything live that they can fit in their mouths! This includes bugs, slugs, snails, other frogs, spiders, worms, mice or even birds and bats if the frog is big enough and the bird or bat small enough.
A few species will eat only one particular food like some smaller frogs might specialize on ants or termites. Aquatic amphibians will eat bugs, other amphibians including tadpoles, fish and small aquatic organisms. There is only one frog species known that is actually a vegetarian: The Brazilian Tree frog eats fruits and berries!
Most tadpoles eat plants and algae in the water. They are important grazers in aquatic systems because they help with nutrient recycling and control algae populations, which help to maintain the health of freshwater ecosystems.
Sometimes tadpoles will eat each other, especially if food resources are low. Some tadpoles eat insect larvae and tiny organisms that are found in the water. Although many species are only active at night, there are some that are active during the day. Amphibians are usually active at night because they are harder to see and can avoid being eaten. Poisonous amphibians that are brightly colored are often active during the day. Bright colors on an animal will warn predators that they are poisonous, so they do not have to worry about predators.
Yes, there are many amphibians that hibernate. Amphibians do not like extreme temperatures. During the cold winter months in non-tropic areas, most amphibians will either hibernate in the mud at the bottom of water or dig down into the ground to hibernate. Some amphibians stow away in cracks in logs or between rocks during the winter.
They slow their metabolism and their heartbeats down and survive off stored body reserves throughout the winter.
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