Tag Archives: tadpoles

Swimming with Frogs

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I wasn’t going to do it again. Really. Surely two frog blogs is enough. But you know what they say: ‘Write what you know.’ Do I know frogs? Well, not in the sense that a herpetologist does – I’m no expert – but I have learned a thing or two just by being around them for the past 18 years. It’s a kind of knowledge by osmosis, that passive process of absorption from the environment. Akin to the way frogs absorb water through their skin rather than drinking it down.

But I never much liked that ‘write what you know’ advice anyhow. After all, if every author complied, there would be no science fiction or historical fiction or fantasy. I prefer ‘Write what fascinates you.’ Of course, sometimes ‘what you know’ is also what fascinates you. And I do find frogs fascinating. So here I go again with yet another frog blog.

‘She finds me fascinating. How thrilling.’

Actually, I’m amazed by all amphibians. Of all the vertebrate classes, only amphibians undergo such radical transformation during their life cycle. Baby mammals look similar to adults only smaller and way cuter. Baby birds look like adults only smaller and, in some cases, way uglier – until they get all downy and adorable. Baby fish and baby reptiles emerge from their eggs looking like miniature versions of their parents.

But members of the class Amphibia have a more complex journey to maturity; more akin to some insects, like butterflies or dragonflies. They don’t just get bigger, they are utterly transformed in appearance, habitat and lifestyle.

Living with frogs has given me the opportunity to observe this fascinating journey at various ages and stages. The cycle begins soon after spring melt, as described in Funky Frogs, and carries on with matching and hatching, as I posted in Frogs, Globs, and Pollywogs. The female lays jellied egg masses attached to twigs underwater. That’s it for maternal care from mama. She just lays lots of eggs and lets nature – natural selection that is – take its course. As pond levels drop, these egg blobs can be stranded high and dry, like the one I’m holding. By this time I can see the embryos wiggling around in their egg sacs and feeding on the algae that colours the eggs green. I put stranded blobs back in the water to give the wee ones a shot at survival.

These are frog embryos, but there’s something distinctly fishy about those tadpoles.

The eggs hatch, releasing the little wigglers into the water. At this larval stage the pollywogs, or tadpoles, seem more like fish than frogs. They live and breathe underwater and suffocate without it. They swim like fish, look like fish, live like fish. But unlike the proverbial duck, they aren’t fish. Because they aren’t done yet.

Next comes the magic – metamorphosis! And this is why I am amazed by amphibians, fascinated by frogs. The tadpole sprouts tiny, skinny hind legs. They are useless, dangly things at first. The pollywog keeps on swimming like a fish, swishing its long tail and breathing through its gills. Then forelegs sprout, mere nubs. But the legs keep growing, becoming stronger and thicker.

‘What the heck are these things anyhow?’ (Yes, I had pet tadpoles at one point.)

And then one day the tadpole uses those legs to venture up into the world of air. I can’t help seeing this moment as a tiny reenactment of those very first animals who emerged from the ocean onto land. What a transformation! The pollywog is now a froglet. It is no longer a fishy thing but looks like a tiny frog with a tail. That tail will be absorbed as nutrient by the froglet and will be the only food it consumes during this transitional phase. The gills will also be absorbed and the frog will breathe through its skin while underwater, or its mouth or lungs on land. This aquatic animal has become a creature of two elements: water and air. It is truly amphibious. And that is the miracle of metamorphosis.

‘I got legs! Maybe I can just hop right up here – Hey! I can still breathe!’

Other Things that Change

And now I turn to a different transformation. I left the Highland Holler at the end of May to spend some time with my family on Vancouver Island. When I left, the pond was already low and gungy with detritus. The shallowest pools had separated from the main pond, as I described in Frogs, Globs, and Pollywogs in June 2021. There weren’t ‘gobs and gobs of jellied egg blobs’ yet, but a fresh crop of amphibians had begun their perilous journey in freshly-laid eggs.

An early egg mass underwater, attached to a twig. The blob in my hand was already high and dry, so I put it back in the water.

I returned home three weeks later to a world transformed. The barren brown of spring had exploded into the verdant green of summer. Trees had leafed, shoots had shot up, and the shrubs and wildflowers (aka weeds) were threatening to engulf the cabin. I’d anticipated a change, but the extent of the growth in such a short time was startling.

But something unexpected and delightful also happened while I was away: L’il Pond was full again, totally rejuvenated by the June rains that fueled all that plant growth. All the pools had filled and joined to form one large pond. The egg blobs were gone, hatched into tiny tadpoles, hidden amidst the bright green aquatic plants. The water was crystal clear, fresh from the Highland lakes.

My view was completely transformed after only 3 weeks away.

All this meant it was time again – time to swim with the frogs! I don’t get this opportunity every year. Often the pond is too shallow and gungy by the time summer rolls around. I was lucky last summer, as described in Ups and Downs in the Holler, and now I was getting another chance.

I hauled my pond gear through the brush and out to the gravel point, which was mostly submerged. I set down my chair and beach bag and was gazing around, trying to decide where to get in, when – Eek! There he was! He was big. He was green. He was a Green Frog. And he was just. Right. There.

If I want to swim, I have to share the pond with this fellah. He’s as big as my hand.

Green frogs are the biggest frogs we have here in Cape Breton. (We don’t, so far as I can determine, have bull frogs on the island.) I wrote about them and other frog species last June, but here’s the recap. The tadpoles take two years to mature and by their second year are bigger than some frog species will ever be. The tads are bizarre looking creatures. To quote myself, they ‘look positively freaky, a kind of FrankenFrog with a full-sized frog-head attached to a tadpole-tail but no torso. Seeing dozens of these scatter in the shallows is a strange sight indeed.’

Photos don’t capture the weirdness and size of these 2nd-year green frog tadpoles.

Given the size of the tadpoles, it’s no surprise that these frogs are the jolly green giants of the pond. And their mating call is as loud as they are big – a percussive ‘Gurnk!’ that echoes around the Holler. Get a bunch of them going at it and they keep me awake at night. Noisy party-animal neighbours! They are also the last to leave the party, still gurnking away long after all the other male frogs have given up on getting lucky.

Green frogs just keep growing … and growing …
… and growing … and growing …

Absurdly, I felt a bit intimidated about going swimming alongside this guy. It’s not like frogs prey on people, like some Creature from the Black Lagoon. But … he’s just so … there. There are all kinds of critters in L’il Pond: Snakes and newts and a myriad of insects at various stages of their complex life cycles. Swimming in the Holler is not for the squeamish. And I’m kind of squeamish. But it just seems silly not to go swimming in my own pond. So, with some hesitation and dithering, I finally waded in, launched myself forward and dove under. It was refreshing and absolutely lovely – and not a single sneak attack by a rogue frog.

What creatures lurk beneath that calm surface?

Then I sat down to dry off, relax, and enjoy the view. The pond level was so high that I set my chair in the shallows. I glanced down and there, right beside me, the miracle of metamorphosis was underway. This froglet seemed unaware of me, perhaps too perplexed by the strange turn his life had taken to care about the giant looming nearby. We hung out together for quite a while, pondering the mysteries of transformation.

My ‘Frog Observation Station’ was perfectly positioned to keep an eye on this froglet.

Now it is August and the pond has once again drained to levels too shallow for homo sapiens swimmers. It’s only fit for frogs and bugs and snakes and newts and for the ducks, sandpipers, kingfishers and such that feed on them. The frogs are content, with a surface cover of lily pads to keep them shaded and hidden from predators, and lots of lovely silty detritus on the bottom.

Happy as a frog in muck.

So I will leave the pond to the local critters now – they need no longer fear a gigantic primate invading their watery habitat. Unless, of course, a post-tropical storm brings buckets of rain to the Holler and refills L’il Pond with clean Highland water. Then I will once again be swimming with the frogs. You can count on it.

Sue McKay Miller
August 10th, 2022

p.s. Uh oh! Look who just landed!

A great blue heron arrived today and is stalking the shallows – watch out Froggie!

Need more frog blogs? Check out:
Funky Frogs and Frogs, Globs, and Pollywogs from May and June of 2021. These cover more frogs species – including spring peepers, wood frogs, pickerels, and leopard frogs – that live in the Holler alongside the green frogs. As always, click on any photo to see it full-size, and please feel free to comment below with observations or corrections.

Ups and Downs in the Holler

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So a funny thing happened. Three days after I posted my June blog on the impact of low water levels, it rained. And rained. And rained. The skies dumped 101 mm in 36 hours. Before this deluge the pond had largely drained into the permeable glacial till. The shallow waters that remained were covered with yellow lily pads and flowers.

On July 3rd L’il Pond had shrunk to a pair of shallow pools speckled with yellow lilies.
Yellow water lilies bloom on the pond while irises and other wild flowers bloom on the banks above.

When the rain began overnight on July 3rd I didn’t expect to see much change in the water level. This time of year, any rain is sucked up thirsty plants to nourish the rich foliage and transpired back into the air. I mentioned as much to a friend who had braved the torrential downpour for a visit.

So I was gobsmacked when we looked out at the pond after some food and chat. I’d just eaten lunch but now I had to eat my words. The lily pads and flowers had vanished. We watched as the rain poured down and the pond rose up, right before our eyes. The lakes on the highland plateau feed abundant brooks and freshets that follow gravity’s lure to the lowest ground, right here in the holler. This funneling effect leads to dramatic rises in water level that never cease to boggle my mind.

By July 5th the pond had risen about 3 metres and spread across the whole holler.

Later that day I took a gander down to the water’s edge. A few days earlier I’d photographed some blooming blue flag irises, high on the banks above the water. Now they were semi-submerged. The rising water had covered the field of marsh grass. And the dried-out pool I described in my June blog, with its sad remnants of desiccated tadpoles, was rapidly refilling with fresh, clean rainwater.

Even after the rain stopped the pond continued to rise as highland waters tumbled into the holler. The water inundated the irises and other flowers, eddied among shrubs and brambles, and reached up to wet the feet of maple and birch. That dried-out pool filled and filled until it spilled over the land bridge that had separated it from the main pond and doomed its tadpole denizens a week earlier. The pond was, once again, a single wee lake, just as it had been back in April.

Too late, alas, for many stranded tadpoles, although at least the bucketfuls I relocated now have plenty of water and time to transform. In Frogs, Globs, and Pollywogs I described my pollywog bucket brigade, saying: ‘I don’t think there’s an ecological issue with this – it’s all one body of water much of the year and is rejoined in summer if a post-tropical storm dumps torrential rains.‘ Well, true enough. But that bit I put in italics? It’s such a rare summer event that I didn’t actually expect it to happen. And I certainly didn’t expect it to happen just four days after I wrote those wistful, hopeful words.

A field of irises high and dry on July 3rd had vanished underwater by July 5th. The second photo is from a different angle because where I was standing two days earlier was underwater.

And what a transformation! Water is the giver of life. Every spring, as the snow melts and the freshets and brooks flow from the highlands to the holler, rushing water is the sound and scent and sight of renewal. So it was strange but exciting to feel that sense of rebirth in early summer. An unexpected gift. Even the local critters were rejuvenated (or maybe just confused?) by this spring-like transformation. The peepers, silent except for a few stragglers, revived their lively chorus. Bird song filled the evening air. It was as if the year had rewound back to early May.

Except … not. I felt a whiff of cognitive dissonance. The rushing waters, frog chorus and birdsong of spring were juxtaposed against the deep-green, chlorophyll-laden foliage of summer. The shoots and sprouts of Spring Ditty had exploded into a jungle of shrubs and wildflowers and brambles engulfing my home. The high water, while welcome, felt a bit weird.

L’il Pond always rises high in spring and autumn, but seldom in summer.
(You can can see the roof of the yurt peeking through the forest across the pond.)

And so this topsy-turvy year continues. It’s been a funny time to begin a blog. Before I started this project I jotted down topics that seemed suited to each season. But I’ve had to scratch some planned blogs (including the one for this month) and several of my posts been slightly out-of-sync with 2021’s slightly out-of-sync seasons. Unlike the deadly heat dome and ongoing drought out west, which has been positively attributed to climate change, it’s difficult to unravel how much of our funny weather is due to climate change and how much is down to the usual variation in weather.

Weather is a chaotic (that is, nonlinear) system and it’s particularly chaotic on this island, jutting out into the Atlantic and buffeted by systems from north, south and west; from land and sea. The deluge that filled the pond wasn’t even a named storm – neither Claudette nor Elsa – but just some random rain event. In Calgary I often heard the old saw ‘If you don’t like the weather, wait five minutes’, but it’s even more apropos in my adopted home.

So pond goes up, pond goes down. I’ll have to wait until next year to see if there are noticeable impacts from this late inundation, but the species that survive and thrive here, from amphibians to alders, are adapted to rapidly changing water levels. Conversely, on a global scale, change is so rapid and extensive that many species don’t have time to evolve and adapt. Species have always gone extinct, but anthropogenic changes are sending the rate of extinction skyrocketing.

Yellow lily flowers basking in the sun were suddenly deep underwater, but are adapted to such changes.

When I worked as a geophysicist I would present my research at scientific conventions and meetings. Like most researchers, I always ended by presentations with words to the effect that ‘more research is needed’. It’s a cliche in science, but it’s also true. Scientific discoveries don’t lead to some totality of knowledge, but to ever more questions. No one today says, ‘Yep, we figured everything out. We’re all done here.’ (Many scientists did say that in the late 19th century, shortly before Einstein blew their minds with relativity theory and Bohr et al. dove down the bizarre rabbit hole of quantum mechanics.) Scientific research is a bit like tackling the mythic multi-headed Hydra: Chop off one head and two more grow back.

My learnings about this place are not remotely systematic or scientific. Rather they are the accumulation of casual observations, recorded in stacks of notebooks and journals over the past 17 years. But the principle still holds. The more I learn, the more I realize how little I know. And just when I think I’ve gained some understanding of the patterns, cycles, and seasons of this place, my assumptions are turned upside down and inside out, as if I’m in some Traveling Wilburys’ song.

So nature continues to surprise and humble me. In the never-say-never department: I wrote In my June blog about swimming in the pond, saying: ‘Not a hope of that this year’. Hah! Joke’s on me. I did indeed swim with frogs. I floated high above lily pads and flowers in that fresh, clean water. And as July passed, those drowned lilies grew up, up, up, drawn toward the light, and the water dropped down, down, down, lured by gravity. Now, at the end of July, those yellow lilies are, once again, breaching the surface to kiss the sun.

Sue McKay Miller
July 30, 2021

Frogs, Globs, and Pollywogs

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A lot has happened here in ‘Frog Holler’ since I posted Funky Frogs. Plenty of matching and hatching, but also, sadly, some dispatching. On the matching front: the wood frogs have long since ceased their wacky quacks. A few lonely bachelor peepers are still hoping for an invite to the mating dance, but I’d say their chances are pretty slim at this late date. Last – but not least – to join the mating game were the green frogs. These big fellas show up late to the pond party and then raise a ruckus. Hmm … reminds me of some people I know.

They are big. They are green. They are frogs. They are … Green Frogs.

Green frogs are by far the biggest frogs in this pond and are (surprise!) green. Their call is a percussive ‘gonk’ that is often compared to a banjo twang. Unlike chorus frogs such as peepers, green frogs are more soloists, but sometimes a gang gets gonking back and forth across the water and it gets rather loud. Due to their size, these frogs are quite startling to encounter on pond walks. They tend to be less skittish than their smaller cousins, being literally ‘a big frog in a small pond’.

Even the green-frog tadpoles are big – they take two years to mature and in their second year look positively freaky, a kind of FrankenFrog with a full-sized frog-head attached to a tadpole-tail but no torso. Seeing dozens of these scatter in the shallows is a strange sight indeed.

The photos don’t capture the weirdness of big green frog tadpoles in their second year.

The two species I see most often are similar in appearance and mating calls: pickerel frogs and leopard frogs. Both tend to be ‘seen and not heard’ – at least by human ears – as their softer calls are drowned out by the loud crowd. The calls have been likened to a soft snore but I’ve heard them on quiet May afternoons and, frankly, it sounds to me more like a fart. A frog fart. Again, frogs are just funny.

A pickerel frog lounging in the mud and a tiny new leopard frog

I see pickerel and leopard frogs in a range of sizes, from super-cute wee ones to mature adults (2-3 years old). They like to sunbathe at the pond’s edge and they usually sense me before I see them. This lumbering giant startles them – perhaps my looming shadow, or the tremor from my seismic footfall. They leap into the water – boing! – and make me jump. Off they go, diving for cover, hiding under the aquatic plants or burrowing into the silty debris until the giant moves on.

Pickerel frogs hop into the water and hide when giants roam the land: ‘You can’t see me!’

On pond perambulations in late May I began to see the results of all that quacking, peeping, croaking, twanging and trilling. Gobs and gobs of jellied egg blobs in the water. Dozens of round eggs are clumped into a jellied mass and attached to a submerged twig. Each egg holds a single visible embryo, wriggling around and feeding on algae that colours the eggs green. Apart from the tiny peeper eggs I can’t tell one blob from another. Or is it even a frog blob? The Holler is also home to newts and salamanders, who are so amazing they will be featured in a future blog.

Gobs of egg blobs. These were laid in deeper water, but became partly exposed as pond levels dropped.

As May turned to June the water level in the pond dropped dramatically. This is an annual event; the pond fills to overflowing as related in Spring Ditty “the snow melt grows the pond into a lake” and then gradually lowers as the water drains into the permeable glacial till. But last winter was a weird one (see April and the Albedo Effect) and the snow melted a month early. We are feeling the impact of that now, with very low water levels. Last June I was swimming in my pond. (Fancy folk swim with dolphins – I swim with frogs!). Not a hope of that this year. By mid-June the pond was down to levels more typical in mid-summer.

As the pond drops, some egg blobs become stranded. Sentimental as I am, I pick them up and toss the whole blob into deeper water. The thing is, I can see the wee embryos wriggling around inside the eggs and I just can’t let them melt into mush. So I scoop and toss, scoop and toss. I have a history of this sort of thing. When I was a child my best friend and I embarked on similar quixotic endeavors, such as putting earthworms, stranded on sidewalks by heavy rains, back on the grass.

Left:many of these embryos are still alive, but not for much longer.
Right: the egg glob stays intact when picked up and tossed into deeper water.

In addition to the egg-glob toss, I often do a pollywog bucket brigade. As the pond drops the deeper areas separate from some shallower pools. A pool may dry out while still teeming with tadpoles who haven’t had time to metamorphose. Without water, they die. So I scoop wiggly pollywogs into a bucket, ferry them over the high ground, and release them into deeper parts of the pond. I don’t think there’s an ecological issue with this – it’s all one body of water much of the year and is rejoined in summer if a post-tropical storm dumps torrential rains.

Left: The drying pool is getting murky, over-crowded and depleted of oxygen.
Right: Clean water, green plants and lots of elbow room (if tadpoles had elbows).

But then again, would the overall frog population be better off without my meddling? After all, frogs have evolved a successful reproductive strategy. Large mammals have few young but tend to them and fiercely protect them until maturity: 1 year for moose, 2 years for bears, 32 years for modern humans (Hee hee). But frogs, like so many organisms, play the odds game. Lay oodles of eggs and swim away.

Almost all those offspring will be eaten or die somehow before they reach sexual maturity, but odds are that a few will survive long enough to keep the species going. One spring, a couple of years on, those few survivors will thaw out or emerge from the mud. The surviving males will peep and quack and croak and trill and twang. The surviving females will select a mate and lay gobs and gobs of egg blobs. And the cycle of life and death will continue.

Left: This pool has since dried out. Right: Yes, this is a bucket of pollywogs, aka tadpoles, rescued from the pool just before it drained completely.

Note: At no time did this reproductive process require a human being tossing egg blobs or bucketing pollywogs. But as I wrote in Hoots in the Holler, nature isn’t all flowers and rainbows. Natural selection has resulted in an astonishing array of organisms but it is not a kindly process. I am trying to learn to accept nature as it is, not as I would wish it to be. To accept these deaths as being as crucial to the cycle as the surge of new life that so delights me every spring. But it is a difficult lesson to learn and I struggle.

I once heard a lecture by the late, great evolutionary biologist Stephen Jay Gould. He explained the role of ‘contingency’ in evolution and gave the example of a successful species going extinct because its pond habitat dries up. And while frogs and other amphibians are in trouble globally, the frogs in the Holler are not about to go extinct because a shallow pool dries up. It is not the scientist in me that is driven to toss egg blobs and bucket pollywogs – it is the sentimentalist. I fret over these wee creatures like a mother, but not like a mother frog. The frog mamas are lounging on lily pads while I run around rescuing stranded eggs and stranded tads. It is somewhat silly, perhaps futile, and certainly more emotional that rational. And that, of course, is why it is so very human.

Sue McKay Miller
June 29, 2021

Just a few from the bucket of pollywogs, released in different areas of the pond.