By Nick Cairns, Sam Jaques and Graham Rothwell
If you live or travel in the southwestern portion of Saskatchewan you know the storms of May and early June put on a spectacular light show with deafening thunder cracks. But if you stay up late enough you may get to hear another natural wonder.
The water brought by these ferocious storms softens the dry cracked soil and fill dugouts, ditches and cattle wallows. These water bodies are then filled with frogs which have spent most of the last year waiting for rain.
Late at night after the first major warm weather storms you can hear the plains spadefoot toad (Spea bombifrons) calling, trying to attract a mate. The sound is impressively loud and can be heard from more than a kilometre away. It sounds kind of like the single quack of a duck - but deeper.
The plains spadefoot toad is not a true toad but belongs to a family of fossorial (burrowing) frogs of arid North America the Scaphiopodidae. These frogs are typified by their vertical pupils (like a cat or a rattlesnake) and a hard “spade” on their hind feet which they use to dig backwards into the soil. They spend almost all their time underground.
Because of the dry habitat of this frog, the breeding pools are usually short-lived and the eggs and tadpole develop quickly. They are distinguishable from boreal chorus frog tadpoles (their most common pond mate) by their larger size, close set eyes and the inability to see an intestinal coil through their belly skin. Most spadefoot tadpoles graze on algae but some can develop into cannibals with more robust jaws if conditions dictate.
|The tiny legs the larger tadpoles sprout already have tiny spades.|
But life as a spadefoot is always dictated by water and they must develop quickly to avoid drying out and dying. From egg to first toadlet it took 5 weeks, from May 27 to July 8.
Now these little frogs will burrow down emerging only at night to feed on insects until they are large enough to breed.