Odd creatures roam our streets by night. Sidewalks too. And driveways, and front and back steps–especially those with lights.
With big eyes, and bellies to match, these beasts are hungry. They’ll stop at nothing in their quest for prey.
But before we cause too much alarm, I should probably clarify a couple things. These animals roam by hopping. Short, clunky, non-threatening hops.
And the prey they seek? It’s mostly in the form of insects.
Yep, this week we’re taking a look at Anaxyrus americanus, the American toad. (I suppose now is as good a time as any to share how bummed I was when this genus name became the norm. For decades these guys were known as Bufo–the Latin word for toad. It’s a great name that fits well; plus, it’s fun to say. The recent switch to Anaxyrus, a name coined in the 1800s, came about as a result of some molecular-level discoveries. The new name may have a physiological basis, but for me, toads will always be Bufos.)
At any rate, American toads are particularly prevalent in our area, probably due to the superb conditions we’ve created for them. Our assorted activities and ventures have made it so that standing water is pretty easy to find. And these guys have taken full advantage.
American toads are what I call “indiscriminate” breeders. Whereas some amphibian species restrict their mating rituals to specific sorts of water bodies, such as ephemeral ponds, for toads, any patch of wetness will do. I’ve found toad eggs in retention ponds, roadside ditches, backyard water gardens, even flooded tire ruts. True, not every tadpole will survive to maturity, but enough do to make American toads our area’s most common amphibian.
However, don’t mistake “common” for “boring.” Toads are anything but!
Well known for the bumps, or “warts,” that cover their skin, toads have two lumps in particular that are quite sizable and contain their most powerful defense. The bumps actually house the parotoid glands. When disturbed, these organs will secrete a milky, bitter-tasting toxin that acts as a deterrent to certain predators.
Have you ever seen a dog or cat react after having an American toad in their mouth? It’s not pretty. Drooling, retching, pawing at the mouth… These are the outward signs. On the inside, their bodies are reacting to the introduction of cardiotoxic steroids that cause pain, swelling and an irritation of the stomach lining.
Before you get too worried, know that the concentrations of these toxic compounds in American toads aren’t high enough to cause cardiac arrest. Cane toads and Colorado River toads, yes. But they don’t live around here. Pet vs. toad encounters in our area just produce localized pain, along with discomfort that can last up to a week, depending on the dog or cat and how much toxin was ingested.
Humans aren’t as likely as animals to put toads in our mouths, but we do occasionally pick them up. Always remember to wash your hands after handling a toad, because those secretions that give our pets problems can also irritate our skin–particularly around the face and eyes. (Not to harp too much, but the powerful compounds causing all these reactions are referred to as bufotoxins. Not anaxyrustoxins. Just sayin’…)
One other truly remarkable feature of toads–in fact, most all frogs–is the way they take in water. I”ll give you a hint: It’s not though their mouths.
Amphibian skin in general highly permeable; in fact, it absorbs oxygen. (The oils from our skin can seriously interfere with this process–which is one more great reason to keep handling of frogs and toads to a minimum.) But there is one region where the skin is not only permeable, but also criss-crossed with an elaborate network of capillaries.
This area, known as a seat patch, enables frogs and toads to absorb water at the end directly opposite from where you’d think they’d “drink.” Hard to imagine, isn’t it? Espeically given all those times we’ve seen Kermit the Frog sipping tea with his mouth. But it’s true, and something to think about the next time you see a frog, or toad, sitting with its belly region pressed into a puddle.
There are lots of other neat things about toads–their acute eyesight; the role their eyes may play in the swallowing of prey; the way they periodically shed and consume their skin. But the best way to gain an appreciation for this prevalent, nocturnal neighbor is to take time to observe one in action.
See how they track their prey? Notice how they gobble it up, even using a forelimb to stuff down the really big bugs? Aren’t these creatures of the night truly amazing?
Yep. I toad you so.
Pam Erickson Otto is the manager of nature programs and interpretive services at the Hickory Knolls Discovery Center, a facility of the St. Charles Park District. She can be reached at 630-513-4346 or potto@stcparks.org.
August 21, 2015
The American Toad
This large and well-fed American toad regularly roams the patio and front walkway at the Hickory Knolls Discovery Center in St. Charles.