June 22, 2014

Boreal Toads on the Move

Yesterday we were hiking in Paradise Valley, and we met two boreal toads migrating from the forest towards the creek.  It was a good thing that they were moving, because otherwise they're really hard to see.  Today I realized that I didn't know much about toads, so I thought I should find out a bit more.

It turns out that boreal toads deserve a bit more admiration from us.  They are the highest elevation amphibian in Canada, and to get through winter, they hibernate underground for up to six months, staying below the frost line.  According to researchers, they mostly use the burrows of golden-mantled ground squirrels, sometimes even sharing them with the squirrels!  The burrows need to be deep enough to prevent freezing, so toads will hibernate up to 1.3 m underground.

Life in the mountains is tough, so female toads lay between 5,000 and 15,000 eggs in late spring to keep the whole show rolling.  Since they live so high, and lay so many eggs, boreal toads contribute a lot to high elevation wetlands: the eggs and tadpoles are food for many aquatic critters.  One time in Kananaskis, we saw a huge school of toad tadpoles, and we both thought, “that's a lot of food.”

The tadpoles transform into toadlets in a couple of months, and then leave the water, which might seem weird, since we usually think of amphibians as aquatic, but boreal toads are mostly landlubbers.  They eat bugs in the forest, and only come back to the ponds for breeding.  They can live to be 12 years old.

One final reason to admire boreal toads: they're beautiful, in their toady kind of way.