Amphibians
Arizona Toad
Anaxyrus microscaphus · also called Arizona toads
Along the clean, flowing edge of a southwestern desert stream, an Arizona toad calls out with a short, high-pitched trill, depending on exactly the kind of running water that damming and diversion projects have increasingly reshaped across much of its range.
Overview
The Arizona toad, Anaxyrus microscaphus, is a stream-dependent amphibian native to clean, flowing desert and canyon streams across a range of the southwestern United States, including Arizona, Utah, and adjacent states. Its unusual preference for running water over still ponds, vulnerability to stream alteration, and tendency to hybridise with the closely related Woodhouse’s toad make it one of the more habitat-specialised and conservation-sensitive toads in the American Southwest.
A toad that needs the water to keep moving
While most toads are content with a still pond or puddle, the Arizona toad has built its entire breeding strategy around clean, flowing desert streams, a specific dependence that leaves it far more exposed to any project that alters how that water moves.
Status
Near Threatened, having declined in parts of its range due to damming, water diversion, and pollution affecting the flowing desert streams it depends on, along with hybridisation pressure from Woodhouse’s toad.
Arizona Toad: common questions
Why does the Arizona toad need flowing water instead of ponds?
This species has evolved to breed specifically in clean, flowing desert streams and rivers rather than the still ponds and ditches most other toad species favour, a habitat preference that makes it unusually dependent on the health and natural flow of specific waterways rather than the more widely available still water many other toads can use.
Why is the Arizona toad considered near threatened?
This species depends on clean, flowing desert streams that have been affected by damming, water diversion, and pollution in parts of its range, and it also faces hybridisation pressure from the closely related Woodhouse's toad where their ranges overlap, combined pressures that have contributed to population declines and its current conservation status.
Does the Arizona toad interbreed with other toad species?
Yes, this species is known to hybridise with the closely related Woodhouse's toad in areas where their ranges overlap, a situation that complicates identification in those zones and raises additional conservation questions about maintaining the Arizona toad's genetic distinctiveness in the long term.
Where does the Arizona toad live?
This species is native to clean, flowing desert and canyon streams across a range of the southwestern United States, including Arizona, Utah, and adjacent states, generally staying close to the specific stream habitat it depends on for breeding.