Head to head
Dixie Valley Toad vs Sonoran Green Toad
A Dixie Valley toad and a Sonoran green toad are both small desert amphibians of the American Southwest that have adapted to extreme, water-scarce conditions in almost opposite ways, one by finding a single permanent water source and never leaving it, the other by disappearing underground and timing its whole life around brief rains.
| Dixie Valley Toad | Sonoran Green Toad | |
|---|---|---|
| Scientific name | Anaxyrus williamsi | Anaxyrus retiformis |
| Range size | Roughly one square mile | Broad, across southern Arizona |
| Water strategy | Permanent geothermal spring | Rain-triggered temporary pools |
| Breeding trigger | Year-round access to spring water | Summer monsoon rainfall specifically |
| Time spent underground | Not especially fossorial | Nearly the entire year |
| When first described | 2021 | Long recognised |
| Main threat | Proposed geothermal energy development | None major |
| Conservation status | Endangered | Least Concern |
Dixie Valley Toad vs Sonoran Green Toad: common questions
Which of these two toads has the smaller range?
The Dixie Valley toad has by far the smaller range, confined entirely to a single geothermal spring-fed wetland covering roughly one square mile in Nevada, one of the smallest known ranges of any amphibian species, while the Sonoran green toad occupies a much broader area across southern Arizona and adjacent Mexico.
Why does the Sonoran green toad spend so much time underground while the Dixie Valley toad does not?
The Sonoran green toad relies on temporary desert pools that only form after summer monsoon rains, forcing it to spend nearly the entire year buried underground waiting for that brief window, while the Dixie Valley toad has permanent access to geothermal spring water year-round, removing the need to hide underground between rare rainfall events.
Why is the Dixie Valley toad endangered but not the Sonoran green toad?
The Dixie Valley toad is Endangered specifically because its entire population depends on one small wetland threatened by proposed nearby geothermal energy development, while the Sonoran green toad's much broader range across southern Arizona means no single development project could similarly threaten its entire population at once.