Also known as the Sonoran Desert toad, the Colorado River toad is one of the largest—and most fascinating—toads in North America. It’s known for its size, its low, melodic croak, and its powerful chemical defenses. If you live in the southwestern U.S., especially around Arizona, this is one amphibian you won’t forget if you see (or hear) it.
Size & Physical Appearance
This toad is a heavyweight among American amphibians. Adults usually measure between 4 to 7.5 inches in length, though some individuals can grow even larger. They have smooth, leathery skin that is dark olive green or grayish-brown, with pale underbellies. You’ll notice small but distinctive white bumps at the corners of the mouth and just above the rear legs—those are parotoid glands, and they play a powerful role in this toad’s survival (more on that later).
Male and female Colorado River toads look pretty similar, but you may notice that males are generally smaller and more likely to be heard calling at night during the breeding season. Juveniles are much smaller, often under 2 inches, and have a darker, more uniform look without the telltale gland bumps being as prominent.
Habitat and Range
This toad thrives in the hot, arid landscapes of the Sonoran Desert. Its range includes much of southern Arizona, a sliver of southwestern New Mexico, and parts of southern California near the Colorado River. Despite the desert habitat, it’s almost always found near a water source—like small ponds, canals, or human-made irrigation ditches. You’ll often find them in lowland desert areas below 5,000 feet in elevation.
They spend much of the year underground, burrowed in moist soil to escape the dry heat. When the summer monsoon rains arrive, they emerge—almost like magic—and breed in temporary rain-filled pools.
Diet
Like most toads, the Colorado River toad is a meat-eater—a voracious one, actually. Its diet includes pretty much anything it can overpower and swallow:
- Insects like beetles, moths, and ants
- Spiders and other arthropods
- Small rodents
- Lizards
- Even other amphibians
They’re ambush predators, waiting patiently for prey to come within tongue’s reach. Then—zap!—the toad strikes quickly with a sticky tongue.
Lifespan
In the wild, Colorado River toads can live around 10 to 15 years. In captivity, with proper care and consistent food, they may live even longer. But in the wild, factors like predation, drought, and road crossings all play a role in how long an individual survives.
Identification Tips
This toad is most often confused with other large southwestern species like the Great Plains toad or the red-spotted toad. Here’s how to tell them apart:
- Colorado River toads are much bigger than most toads in their range—think hand-sized.
- Look for the behind the eyes—they’re white and noticeable.
- Their call is a low-pitched “whirr,” almost like a soft outboard motor.
- Unlike most toads, their skin is relatively smooth and somewhat shiny.
Also worth noting: these toads are mostly nocturnal. You’ll probably see them at night after a rainstorm, especially near light sources where insects gather.
Fun Fact
Here’s where this toad gets famous—or infamous. The Colorado River toad secretes a powerful toxin from the glands behind its eyes. This toxin is strong enough to sicken (or even kill) pets that pick the toad up in their mouths. But it also contains a compound called 5-MeO-DMT, a powerful psychoactive substance. Some people have tried using it recreationally—though this is illegal in the U.S. and harmful to the toads and potentially dangerous to humans.
If you find one, it’s best to observe from a distance and never handle it, especially without gloves. And definitely keep curious dogs away!
Bottom Line
The Colorado River toad is a fascinating and unique part of the desert ecosystem. With its giant size, cavernous croak, and surprising chemistry, it’s definitely one of the more memorable amphibians you might come across in the Southwest. Just remember—look, don’t touch!