Canada has a total of 49 amphibian species – 2 newt, 1 mudpuppy, 20 salamander, 18 frog and 7 toad species – found in all provinces and territories.
Most of these animals are found in the southern portion of the country, but one tiny frog – the Wood Frog – can be found as far north as the Northwest Territories, Nunavut and The Yukon.
In a country where much of the fresh water freezes solid thoughout the winter months, our amphibians are masters of survival.
Hiding Below The Ground
Many species use abandoned animal burrows, or self dug burrows, to escape the freezing winter conditions or long summer droughts.
Temperatures in the ground below frost level are wam enough for them to survive the winter, and cool enough for them to withstand scorching summer temperatures and hot, dry periods.
Aquatic amphibians may spend the winter in water that is too deep or fast flowing to freeze solid. There is enough oxygen beneath the ice to keep them alive. Tadpoles and salamander larvae may spend the winter buried in the mud at the pond bottom.
Freezing & Thawing
Some frogs are freeze tolerant, and survive temperatures as low as -6C. Their body increases specialized protein and glucose to protect the cells from freezing and drying. Ice crystals form beneath the skin and through the muscles. Up to 60% of body fluids freeze, circulation stops and the heart stops pumping. In spring they thaw and resume life.
Strength in Numbers
For many salamander species, communal nesting sites are the answer. Multiple femailes will lay their eggs in a partiocularly choice site, rather than use a less desireable one on their own. This improves the chance of a successful hatching, and is common in areas where good nesting sights are scarce.
Darker is Better
Dark colours absorb heat from the sun more readily than lighter ones. Larvae of most amphibians are dark green, brownish or black. They often swarm together, increasing the size of the mass to absorb more heat. Eggs are also laid in large masses so the small dark embryos can attract more heat. The thick jelly holding the eggs together acts as an insulator against the cold.