Earlier this month, the National Park Service had to release a warning letter to all park visitors stating that they should not lick or have any kind of tongue contact with the Sonoran Desert Toad (Bufo alvarius) often encountered here. Strange, as it’s typically common sense not to lick any animals. Also known as the Colorado River roads, the National Park Service acknowledges that they “have prominent parotid glands that secrete a potent toxin,” Park Service said.