Amphibians

Amphibians were the first animals to adapt to terrestrial life and acquire four limbs millions of years ago. Nowadays, they are at grave risk, more than any other vertebrate class.

Amphibians are ectothermic (cold-blooded) vertebrates with an interesting life cycle. They normally begin their lives as aquatic fish-like larvae after hatching, developing into terrestrial adults. They breathe through gills in the first part of their life cycle and then via the lungs as adults. We call this change of shape metamorphosis. While adults live mainly on land, they typically return to water to breed. Amphibian eggs lack shells and are instead encased in a gelatinous material.

In contrast to reptiles, amphibians have smooth, fragile skin that requires constant moisture. Since many amphibians have large eyes, they may easily identify their prey even at night. Depending on the temperature, amount of light, or mood, some amphibians also alter the color of their skin.

Some of these amphibians have developed unique defense mechanisms, including the secretion of toxic substances through their skin, in order to deter predators. Take, for example, poison dart frogs, which are characterized by their strikingly bright colors that serve as a visual warning to potential predators about their high toxicity.

Unfortunately, amphibian populations worldwide are facing severe threats, including habitat destruction, pollution, climate change, and the spread of diseases like chytridiomycosis. These factors have led to declines in many amphibian species and, in some cases, even extinction.