Toads do not have warts - Parotoid glands

Western toad - photographed in Waterton National Park, June 29, 2025

"Don't pick up that toad!  You'll get warts!"  Have you ever heard that one?  Call it folklore or an urban legend, it has no bearing in reality.  Warts are caused by particular viruses (HPV - human papillomavirus) that infect the skin and are typically found on hands, feet, and arms.  There are over 100 strains of HPV, and only Type 6 and 11 are responsible for the sexually transmitted type.  Toads neither have warts nor do they cause them.  They are not carriers of HPV (notice that the first word is Human).

So, what are those bulging bumps on the back of a toad - especially just behind the eyes?  Those are parotoid glands.  They are easily breakable and release a toxic creamy substance that will likely surprise anything that tries to eat it.  There are a variety of chemicals, the most toxic being bufadienolides.  These are a type of cardiac glycoside, a group of poisons that are enzyme inhibitors and may result in heart problems, paralysis, or nausea.  

The skin of all amphibians tends to be toxic, some more than others.  Cane toads have some of the most toxic secretions.  The release of cane toads in Australia has caused the death of many predators as they haven't developed any level of immunity to the chemicals.  I caught one in Fiji, you can read my blog on that here.  In North America, the rough-skinned newt has extremely toxic skin; it has been estimated that one newt has enough poison to kill 50,000 mice.  I caught one on Vancouver Island a few years ago.  You can touch them, just don't take a bite.  I wrote a blog on the newts; you can see it here.

Interestingly, toxins extracted from toads has been an important part of Chinese medicine for centuries.  It turns out that the toxin can be used to treat some forms of cancer.  The problem, of course, is that it also causes cardiac and other medical issues.  Modified toxins are being explored for any therapeutic benefits they may have.  Who knows what future applications may come from the secretions of the toad's parotoid glands.

Thanks for reading.

Eric Svendsen     www.ericspix.com 


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