do most salamanders only have terrestrial life stage

Salamanders are a diverse group of amphibians, and their life stages vary depending on the species. While many salamanders have both aquatic and terrestrial life stages, some spend most or all of their lives in water, while others are primarily terrestrial. Here are some general observations:

1. Aquatic Salamanders: Some species, like the axolotl (Ambystoma mexicanum), spend their entire lives in water. These salamanders have external gills or specialized skin that allows them to breathe underwater. They do not undergo metamorphosis to become terrestrial.

2. Metamorphic Salamanders: Many salamanders have a life cycle that includes an aquatic larval stage and a terrestrial adult stage. The larvae, often called "waterdogs" or "salamander larvae," live in water, breathe through gills, and have a laterally flattened tail for swimming. During metamorphosis, they develop lungs, lose their gills, and transition to a more terrestrial lifestyle as adults, although they may still be found near water sources.

3. Primarily Terrestrial Salamanders: Some salamander species are predominantly terrestrial throughout their lives. Examples include various lungless salamanders (family Plethodontidae), which live in moist environments like forests and do not require a water body for their life cycle. They have lungs (though many have reduced or lost them over time) and rely on cutaneous respiration (breathing through their skin).

4. Neoteny: In some cases, salamanders retain juvenile characteristics into adulthood, a phenomenon known as neoteny. For example, the axolotl is neotenic, meaning it retains its larval features like gills and does not undergo metamorphosis.

5. Adaptations: The life stages and habitat preferences of salamanders are closely tied to their specific adaptations. Aquatic salamanders may have more developed tails for swimming, while terrestrial salamanders often have shorter, more robust limbs for crawling or burrowing.

In summary, while many salamanders do have a terrestrial adult stage, there is a wide variety of life stages and habitat preferences among different salamander species. Some are exclusively aquatic, others are primarily terrestrial, and many undergo transitions from aquatic to terrestrial environments during their life cycles.