Dream Frogs

…I hear the dream frog at a distance…My dream frog turns out to be a toad.

~Henry David Thoreau

In a post in late February I discussed the vocalizations of a variety of frogs and toads I have photographed in North Carolina. Last week I had the opportunity to spend some time with one of my favorite spring-time songsters, the American Toad. All I had with me was my iPhone, so the image quality is a bit limited, but it was an amazing sight. It was in a seemingly unlikely place, a rocky Piedmont stream. I usually find these toads along sandy or muddy shores of pools, ponds, lakes, or even water-filled tire ruts in a field, but here they were trilling along what could almost pass for a mountain stream. As I mentioned in the other post, the far-off trill of American Toads reminds me of some alien spaceship sounds in a cheap sci-fi thriller. To Thoreau, they were his dream frogs.

American Toad calling head-on

American Toad calling

He described it as a trembling note, some higher, some lower, along the edge of the earth, an all-pervading sound. Nearer, it is a blubbering or rather bubbling sound, such as children, who stand nearer to nature, can and do often make. Indeed, the call is easily imitated by one of two methods – the lip flap, or the tongue flutter (some people are apparently capable of only one of these methods). Go ahead, practice it – probably best done when no one else is around….purse your lips and blow air out of them while making a high-pitched humming sound (the lip flap); or let out a high-pitched hum while vibrating the tip of your tongue on the roof of your mouth (the tongue flutter). Now, doesn’t that feel good? Let’s see how you compare to the real thing…

Thoreau is correct in saying that the closer you are to the calling toad, the less dream-like the quality, but it is still an amazing sound. His comments on the visual aspect of a group of toads that were froggily lusting are also worth noting…

After an interval of silence, one appeared to be gulping the wind into his belly, inflating himself so that we was considerably expanded; then he discharged it all into his throat while his body or belly collapsed suddenly, expanding his throat to a remarkable size. It was a ludicrous sight, with their so serious prominent eyes peering over it; and a deafening sound, when several were frogging at once, as I was leaning over them.

Deafening indeed. And last week it came in waves. First one, then another of the suitors would trill, often with four or five all at once. And all of this sound was for the sake of one large female toad in a stream side pool. But she was already preoccupied with one of the lucky fellows in a behavior known as amplexus (Latin for “embrace”).

amplexus

In amplexus, a male toad grabs the larger female under her armpits with his front legs and holds on. As the female deposits eggs, the male releases sperm into the water and fertilizes them. I have seen anuran amplexus many times, but had never witnessed the actual egg-laying until last week.

Laying eggs

As I tried to get some video of calling males, the coupled pair maneuvered over to a quiet pool and began to deposit eggs. The female crawled into slightly deeper water, submerging the pair. The male moved his hind feet and it appears as though he was catching the eggs as they were being released, presumably to ensure fertilization.

This went on for several minutes until he finally moved his feet onto her back and she started crawling around leaving a string of eggs behind. At that point, I turned my attention to the bevy of trilling toads still trying for a chance. At times like these, male toads will often skirmish with one another or mistakenly grab anything that moves. One of my all-time favorite museum workshop quotes occurred one night while leading an amphibian program. We were watching a group of American Toads as they were froggily lusting and my co-lead, Alvin, showed us all something that only esteemed herpetologists know. As a male toad was swimming toward us, Alvin told the group that these guys will often grab onto anything that moves during these breeding bouts. As he spoke, he placed two fingers in the water and wriggled them, making a ripple that the toad immediately picked up on. The toad swam quickly toward the moving fingers and clasped them in its best amplexus move. Alvin pulled it gently out of the water, the toad still hanging on. One teacher exclaimed, “Oh My God, he’s a frog whisperer”…a high honor indeed. When the grabbee is another male toad, instead of a pair of herpetologist fingers, something else happens.

Male American Toads give something called a release call when they are grabbed in an amplexus-style manner (in the armpits). The short clip above ends with one male grabbing another, followed by a quick chirping release call.

toad eggs

Strands of American Toad eggs

American Toad eggs

A mass of American Toad eggs in a stream side pool

The result of this frenzy of activity is, of course, a new generation of toads. Females lay a double strand of eggs that may be several feet long (she may lay several thousand eggs each season). Tiny black tadpoles hatch within a week or so. While this rocky stream breeding habitat may have an advantage over certain shallow pools that might dry up in hot weather, I bet there is a high probability that the eggs or tadpoles can be washed downstream in heavy rains. But something must be working as there certainly were a sufficient number of toads attending the breeding session that night.

I laid on the rocks and watched and listened to the toads for over an hour. It was a mesmerizing scene and one that they did not seem to mind sharing with an observer. I’ll leave you with more of Thoreau’s observations on his dream frogs…

You would hardly believe that toads could be so excited and active. It is a sound as crowded with protuberant bubbles as the rind of an orange. A clear ringing note with a bubbling trill. It takes complete possession of you, for you vibrate to it, and can hear nothing else.

The toads completely fill the air with their dreamy snore; so that I wonder that everybody does not remark upon it and, the first time they hear it, do not rush to the riverside and the pools…

 

 

 

 

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