Frog Friday

You can’t tell by the look of a frog how far they’ll jump.

~Paul Doiron

Took a stroll around the property yesterday, camera in hand, looking for the tiny creatures who share these woods. One thing really impressed me – the amazing number of spider webs that seemed to block my way at every turn. When I spotted one, I tried to side step it so as to not ruin a night’s work, but I still managed a head full of silk strands (luckily, it blends in well). While focusing on the tiny subjects without backbones, I caught a quick movement over by the wet weather stream in our ravine. I looked, and saw nothing, but I suspected I knew what it had been. I turned, and stepped in that direction, and off it went, a Northern Cricket Frog. I leaned in for a photo but it leapt into the creek and disappeared.

northern crickrt frog

A more cooperative Northern Cricket Frog, Acris crepitans (click photos to enlarge)

Just a few steps more, and I encountered another, this one resting at the base of large tree. This is a common species here and I find them down along the creek and in our yard in the vicinity of our two water gardens (although they often wander far from standing water). Their calls sound like clicking two pebbles or pennies together. They are excellent jumpers for their size, often leaping more than 3 feet to escape danger (or silk-covered giants).

 

northern crickrt frog from above

Cricket frogs blend in with their surroundings

They are small frogs, reaching a little over an inch in length. They can be identified by the backward-pointing triangle between the eyes (the color can be quite variable, but usually either brown or green). They often have a contrasting color, Y-shaped stripe, going from that triangle down the back (in this one it is a very faint cream color, but is often much more noticeable). This species is replaced by the Southern Cricket Frog as you move toward the coast.

green treefrog dorsal view

A Green Treefrog, Hyla cinerea, outside our window

When I got back home, I was watching the butterflies and hummingbirds feeding just outside the sun room window when I noticed a green lump on one of the Jewelweed stalks. It was one of my favorite frogs, a Green Treefrog. We are at the western range of this beautiful species, but we have had one every year for the past several years (I’ve never found more than one and never heard them call here). Online resources say this species can live up to 6 years in captivity, but that would surprise me if this is the same individual, year after year, but who knows.

green treefrog side view

The diagnostic white racing stripe down the side

One of the things I love about this species is their Buddha-like presence, as if they are serenely contemplating the world around them while maintaining a stoic position of deep reflection (have I been self-isolating too long?).

green treefrog ready to move

The frog finally tired of my presence and camera flashes, and moved as if to jump, so I departed to leave it in peace

Plus, they are just a beautiful creature – the colors, those eyes, the enlarged toe-pads, all an incredible design that helps them blend into and function in their green world. After a few shots, the frog started to move, so I stepped away and let it return to its composed demeanor. Perhaps I can learn something about our current condition from these frogs…stay calm, or leap like crazy when it gets to be too much. Be like a frog…

A Frog in My Throat

Frogs are the birds of the night.

Henry David Thoreau

There is something magical about the sounds of frogs and toads. In my museum days, I used to do a workshop activity where participants got a call sheet for a local frog or toad species. Each sheet had a photo and a description of the amphibians’ song. Teams imitated their call and then we would listen to a recording, and each group would try to identify their species’ real call. People always loved imitating the sounds and hearing the recordings, but few could match the quality of the actual amphibian voice.

Part of the reason may be the special adaptations that frogs and toads have for communicating with one another. The most visible asset is their vocal sac.

Upland Chorus Frog calling side view 2

Upland Chorus Frog calling (click photos to enlarge)

The vocal sac is an elastic membrane originating from the floor of the mouth of most male frogs. It tends to be thinner on many of the smaller frog and toad species that call in air, and more thick-walled on the larger species, like Green Frogs and Bullfrogs, that call in water. Vocal sacs come in a variety of shapes and sizes, and can be single or paired. To initiate a call, a frog inflates its lungs, and closes its mouth and nostrils. Air is then forced out of the lungs through the larynx and into the vocal sac, which then enlarges. To create the series of sounds typically categorized as the advertisement or mating calls, the air is passed back and forth from the vocal sac to the lungs without being expelled. While it appears that the vocal sac helps to radiate and amplify the sound, studies have shown that other body parts, especially the “ears”, or tympanic membranes, also play an important role in amplifying the call notes of certain species.

When seen from behind, as in the short video clip below, it is clear that this sound-producing activity must be a lot of work for a male frog.

Some scientists also speculate that the act of calling is both the most energy-draining and predation-risky behavior that a male frog or toad exhibits. But, aren’t we glad they do? It is a fascinating behavior to observe, and the sounds produced are a wonderful addition to our natural sound-scape. I imagine the female frogs and toads appreciate it as well.

Below are a few photos I have taken over recent years of frogs and toads calling in a variety of habitats in North Carolina. I look forward to adding photos of more species in the coming months.

The Pickerel Frog has paired lateral vocal sacs that produce a low-pitched call sounding like a human snore.

Pickerel Frog calling top view

Pickerel Frog

One of our earliest frog songsters, the Spring Peeper repeats his high-pitched note about once every second. One reference stated that researchers estimate a male Peeper may repeat his call up to 4,500 times in a single night.

Spring Peeper calling

Spring Peeper

The harsh trills of the Cope’s Gray Treefrog can be heard in many North Carolina forests and neighborhoods throughout much of the summer.

Gray Treefrog calling

Cope’s Gray Treefrog

Considered by many to be our most beautiful frog, the Pine Barrens Treefrog is found primarily in the Sandhills. It became the Official State Frog in North Carolina in June, 2013.

Pine Barrens Treefrog

Pine Barrens Treefrog

Fowler’s Toads are abundant in the Piedmont. Their nasal call (“waaaaah”) can be heard from about April through July.

Fowler's Toad calling

Fowler’s Toad

A chorus of trilling American Toads always reminds me of what a group of distant alien space ships might sound like in early sci-fi films.

American Toad calling

American Toad

Thoreau (no surprise here) had a more eloquent take on the sound of the American Toad…

Close by, it is an unmusical monotonous deafening sound, a steady blast (not a peep nor a croak – but a kind of piping). But far away, it is a dreamy, lulling sound, and fills well the crevices of nature.

Toad calling reflection

American Toad reflection

Thoreau also had some intriguing insights on how we may share some similarities with the amphibians singing in our neighborhood wetlands…

I see the relation to the frogs in the throat of many a man. The full throat has relation to the distended paunch.

Not sure where ol’ Henry was going with that one, but this final thought seems clear enough…

The music of all creatures has to do with their loves, even of toads and frogs. Is it not the same with man?

Gray Treefrog vocal sac backlit

Cope’s Gray Treefrog vocal sac backlit