why salamanders have no hind limbs and very tiny forelimbs

The reason why certain salamanders have no hind limbs and very tiny forelimbs is due to a phenomenon known as limb reduction or limblessness. Limblessness has evolved independently in multiple lineages of salamanders, resulting in different limb configurations.

To understand why this occurs, we need to look at the ecological and evolutionary factors at play. Salamanders with reduced or absent limbs typically live in specialized habitats such as underground burrows, caves, or aquatic environments. These environments might offer different selective pressures compared to those faced by salamanders with well-developed limbs.

One possible explanation for limb reduction in certain salamanders is that it allows them to move more effectively through narrow spaces and burrows. Limblessness reduces the overall body size and streamlines their body shape, helping them navigate through tight spaces and crevices where limbs would be a hindrance. In aquatic environments, reduced limbs may provide better hydrodynamics, allowing for more efficient swimming.

Evolutionarily, these changes in limb size and structure may occur over time through a process known as natural selection. Individuals with limb variations that enhance their fitness in their specific ecological niche are more likely to survive and reproduce, passing on their genes to the next generation. Over generations, the population gradually adapts, leading to the prevalence of limbless or reduced-limb salamanders.

To further investigate the specific reasons for limb reduction in a particular salamander species, we could look at scientific studies and research articles focused on the species in question. These studies often involve a combination of field observations, genetic analysis, and laboratory experiments to gather evidence and draw conclusions about limb development and evolution.