do some salamanders can breathe by enternal gills

Yes, some salamanders are indeed capable of breathing using external gills. This ability is particularly common among aquatic salamander larvae (such as those belonging to the family Ambystomatidae, which includes the axolotl). These gills are specialized respiratory organs that allow them to extract oxygen directly from water.

Here are some key points about salamander gills:

1. Development: Larvae of many amphibians, including salamanders, typically develop external gills during their early stages of life. These gills are usually visible as feathery or filamentous structures near the rear of the head or along the sides of the body.

2. Function: External gills allow salamander larvae to live in an aquatic environment and breathe without lungs. They absorb oxygen from the water through these specialized structures, which are rich in blood vessels.

3. Metamorphosis: As salamanders undergo metamorphosis, transitioning from an aquatic juvenile to a terrestrial or semi-aquatic adult, they typically lose their external gills. Instead, they develop lungs, which becomes their primary organ for respiration. However, many adult salamanders retain a high degree of lunglessness (lunglessness is known as aplisia) and may rely on cutaneous respiration (breathing through their skin), especially in moist environments.

4. Axolotls: The Mexican axolotl (Ambystoma mexicanum) is a notable exception; even as adults, they retain their larval features, including external gills. They remain entirely aquatic throughout their lives and are neotenic, meaning they maintain juvenile characteristics as adults.

5. Other Examples: Other salamander species that have aquatic larvae with external gills include lungless salamanders (family Plethodontidae) and the Eastern newt (Notophthalmus viridescens).

The ability to breathe using external gills is an essential adaptation for salamanders in their early life stages, allowing them to survive in aquatic environments before they transition to more terrestrial habitats or remain aquatic as adults, like axolotls.