Toad Breath: American Toad

I’m sitting out on the deck, enjoying an evening chorus and glass of wine when that familiar trilling floats through the soundscape. There are lots of birds out there, but this isn’t a bird. It’s an American toad. He’s been hibernating over the winter, and now the ground temperature tells him that spring has arrived. It’s time to make his way up to the surface and begin trilling his lovesong.

The toad gets a bad rap. In the Middle Ages, toads were considered familiars with witches. That is, they were spirits in toad form who helped the witch do her magic. A century later, Shakespeare had the witches in McBeth adding the toad to their caldron as a poisonous ingredient in witches’ brew. And up to modern times, the belief is still strong that touching a toad will give you warts. It won’t. The toad keeps the warts for itself.

The warts are actually groups of glands that contain a poisonous concoction. When the toad is threatened, it can produce this bad-tasting milky substance which contains poisonous antibiotic compounds to deter or poison small predators. The poison is not dangerous to humans unless it is ingested or gets in the eyes. It can kill small mammals, though. The hognosed snake, the American toad’s principle predator, is immune to toad poison. So when a toad is threatened by a hognosed snake, it puffs itself up as big as it can to make it hard for the snake to swallow it.

The American toad (Anaxyrus americanus) is native to North America, and lives where it can find dense patches of brush to hide and hunt in, a supply of insects, and semi-permanent to permanent bodies of water where they lay eggs and spend their tadpole days. If a toad reaches adulthood, and the odds are not in their favor, they will reach sexual maturity in two to three years and may live up to ten years in the wild.

The adult toad is two to three and a half inches long and is generally brown to gray. It has spots on its back that contain poison glands, and two bigger glands just behind its eyes. His belly is white with more spots. He has short legs and a stout body and thick skin with noticeable warts.

When they mate, in shallow ponds or other bodies of water, the female toad discharges thousands of eggs in a long, jelly-like spiral tube.  The male discharges his sperm into the water around the eggs, and then their parenting is done.

Tadpoles hatch in a few days and spend a couple of months growing, molting, and changing into adult toads. More likely, though, they become tasty morsels for fish and other pond inhabitants. The toads that make it to adulthood move out of the water onto dry land and begin their toad lives catching insects with their long and very sticky tongue. So toads help keep insect pest populations down for gardeners.

American toads thrive in gardens, backyards, fields and forests, and in the yard on Owl Acres. The trilling we hear is a sustained single-pitch trill that lasts anywhere from four to 20 seconds each.

Have you ever wondered how a toad breathes? Okay, that’s probably not the first thing you think of when you wake up in the morning. It probably doesn’t even cross your mind when you hear a toad trilling in the grass. I found myself wondering about it though. As amphibians, toads have more than one way to get the oxygen that they need to survive. When a toad hatches from its egg, it’s a tadpole. Tadpoles have gills like fish. They pass water through their gills, exchanging oxygen and carbon dioxide rather like we do breathing air. They can also absorb oxygen from the water through their skin. But sometimes the water is low in oxygen, so the tadpole has to find a way to get more. At first it’s too weak to break the surface tension of the water, so it sticks its mouth to the underside of the surface and sucks in a bubble full of air. Because it has lungs as well as gills, it can use this bubble. When it’s bigger and stronger, the tadpole will just gulp air at the surface when it needs it. Tadpoles undergo metamorphosis when they’re a few weeks old, losing their tails and gills, and growing strong hind legs. As toadlets now, they move onto the land where they breathe air using their primitive but well-developed lungs. They don’t have a diaphragm to help them breathe, so they use the muscles in the mouth and throat to act like a pump pushing air into the lungs and sucking it back out. They can’t get enough oxygen this way, though, so they supplement it by absorbing oxygen directly through their skin and thin membranes in their mouth. They can breathe through their skin underwater, too, although they still have to come up for air. Toads dig into the ground to hibernate through the winter. During this phase, they don’t use their lungs. They get all the oxygen they need from the surrounding soil diffused through their skin. But this means that their activity level has to be very low. 

Handling a toad won’t give you warts, but it is likely to be hard on the toad. Handling it may damage the toad’s sensitive skin. Let’s leave them to their business. They can catch up to a thousand insects per day.  

Photo by Andy Reago & Chrissy McClarren