Tell apart Iowa toads

Al and Wally, named for conservationist Alfred Wallace, are two Great Plains toads (Anaxyrus cognatus) that live at the Dickinson County Nature Center.

Four different toads live in Iowa — Great Plains toad, American toad, Fowler’s toad and Woodhouse’s toad — and they can be difficult to tell apart. Here are a few key ways to tell what kind of toad you have seen:

Coloring

Many toad species vary in color from green to brown to gray to rust-colored.

Photo of Great Plains toad

Photo of Great Plains toad

The Great Plains toad has a white belly that may occasionally have some spots but is often blank. The blotches on this toads have a contrasting white border.

American toad

American toads have a pale belly with fine black spots, and they have black spots on their back that are edged by white or yellow.

Photo of Fowler's toad

Fowler’s toad

Fowler’s toads have a white belly with a single black spot on the chest and a light stripe that runs down the middle of the back.

Photo of Woodhouse's toad

Woodhouse’s toad

A Woodhouse’s toad is typically lighter in color and has a white stripe running down its back.

Warts

Toads have warts that secrete a fluid that makes a toad distasteful to predators. It can even make them sick.

American toads have one-two warts per spot; Great Plains toads have several warts per spot. A Woodhouse’s toad has three or more warts per spot.

Eye ridges

Toads have glands on their head called parotoid glands, and they also have cranial crests — ridges behind their eyes. These can be differentiators between species.

Woodhouse’s toads have two parotoid glands pressed tightly against their cranial crests, as do Fowler’s toads. American toads have two parotoid glands that are either completely separate from the cranial crests or are connected by a small spur.

Photo of back of American toad

American toad, photo by Rhododendrites via Wikimedia Commons

Great Plains toads have two parotoid glands that touch the ends of the cranial crests. Their cranial crests meet in front of the eyes to form a point.

Location

The Great Plains toad and Woodhouse’s toad can be found most along the western edge of Iowa. The Fowler’s toad has a small distribution in southeast Iowa, and the American toad is common throughout the state.

Sound

The three toads in northwest Iowa also have very distinctive calls.

American toad

Great Plains toad

Woodhouse’s toad

 

 

 

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