The U.S. National Park Service urged the public not to lick Colorado river toads in a Facebook post. The toad has skin that contains toxic organic substances.
These toxins have been known to paralyze or kill dogs. Officials say these toxins can also harm humans.
"These toads have prominent parotoid glands that secrete a potent toxin," the National Park Service said. "It can make you sick if you handle the frog or get the poison in your mouth. As we say with most things you come across in a national park, whether it be a banana slug, unfamiliar mushroom, or a large toad with glowing eyes in the dead of night, please refrain from licking."
They are among the largest toads in North America, measuring nearly 7 inches.
These toads are commonly found in the Sonoran Desert in Arizona.