Spotted salamander found at the edge of a vernal pool in one of the City of Ann Arbor’s Nature Areas. Photo: Derek Smith
Spring is not just a time for blooming flowers. It’s also the peak breeding season for many Michigan amphibians.
Mole salamanders (genus Ambystoma) are named for their burrowing behavior. They spend most of their adult lives inside their burrows and out of sight, but they emerge in the early spring to breed. The salamanders migrate en masse during the first warm, wet nights of the new year, leaving their burrows for their breeding grounds – seasonal pools in wooded areas. The pools are filled with water throughout the spring, an important requirement for amphibians, which must lay their eggs in water. But, many of these pools eventually dry out during the summer, which makes them truly ideal for raising larval salamanders and tadpoles. Because the pools are temporary, fish – which eat amphibian eggs and larvae – cannot live in the pools, allowing tadpoles and larval salamanders to grow up free from these voracious predators. In fact, many amphibian species breed exclusively in seasonal pools.
This year’s spring salamander migration has largely finished. Adult salamanders have left the pools, retreating to hide under logs or in burrows, but their eggs will generally remain in the pools for around a month, and the larvae can be found in the pools for another two months after hatching (although the hatching and development times vary with temperature). Afterwards, the larval salamanders grow lungs and start their life on land as young adults.
A blue-spotted salamander found near a buttonbush swamp on MBGNA property. Photo: Derek Smith
Spotted salamander found at the edge of a vernal pool in one of the City of Ann Arbor’s Nature Areas. The salamander is sticking its head out of a leaf-litter burrow. Photo: Derek Smith
