do most salamander species only have terrestrial life stage and never live in water

No, most salamander species do have an aquatic life stage at some point in their development. Salamanders belong to the order Urodela, which includes three main families:

1. True Salamanders (Salamandridae): This family comprises the true salamanders of Europe and Asia. The juvenile stage, known as the larval stage, is typically aquatic. During this stage, they breathe through gills and have a laterally compressed tail for swimming. As they mature, they undergo metamorphosis to become terrestrial adults that breathe through lungs.

2. Newts (Salamandrinae): Newts are a subfamily within the Salamandridae family. They also have an aquatic larval stage with gills and laterally compressed tails. After metamorphosis, they emerge into terrestrial adults.

3. Mole Salamanders (Ambystomatidae): Found in North America, mole salamanders, also known as hellbenders, include species that lay eggs in water. Their aquatic larvae resemble those of newts and true salamanders, but they usually metamorphose into large, lung-breathing adults that are predominantly terrestrial.

While most salamanders do pass through an aquatic larval stage and later transition to a terrestrial lifestyle, there are exceptions:

• Some salamander species, like certain types of axolotls (Ambystoma mexicanum), retain their gills throughout their lives and remain aquatic or semi-aquatic.
• A few species, such as the tiger salamander (Ambystoma tigrinum), may skip metamorphosis under certain environmental conditions and remain neotenic (in a perpetual larval state).
• Some terrestrial salamanders, like the