Frogs are vertebrates because they have a full skeletal structure that includes a spinal cord. The term vertebrate is derived from the word “vertebrae,” which is a bone in the spinal cord.
A vertebrate is a type of animal that has a series of nerves running from the brain down its back, covered by a special series of bones. These bones, called vertebrae, compose the spine and both protect the nerves and allow the animal a unique range of motion compared to less-evolved species.
Frogs, along with salamanders, are classified as amphibians. These types of animals are vertebrates that live in typically forested areas near bodies of water, such as lakes or ponds. Their major distinction from other similar animals, such as reptiles, is that they lay their eggs in the water instead of in nests on land.
When a frog becomes pregnant, it lays its eggs in a specially crafted area of ground underwater. When the eggs hatch, baby frogs, called tadpoles, emerge and spend the early parts of their lives in the water. Initially, tadpoles have tails that they use to swim through their watery environments. Over time, they lose their tails and grow four limbs, eventually leaving the water to spend some time on land.