formerly Rana sylvatica
Wood Frog / Grenouille des bois
This is a moderate sized, true frog with prominent
dorsolateral ridges. It may be
reddish, tan or dark brown with a dark mask that ends abruptly behind the
tympanum. Some individuals
have a light line down the middle of the back. There is a dark blotch on the chest
near each front leg. The belly is white and there may be some dark mottling. The toes
are not fully webbed. Adults may reach up to 8 cm.
is a series of sharp quacks, almost like a duck. The call of
Cope's Gray Treefrog is similar but more
musical and with more trill.
In eastern Canada there are no other frogs with both a mask and dorsolateral ridges. In
western Canada, Columbia Spotted Frogs,
Oregon Spotted Frogs and
Northern Red-legged Frogs can all have a dark mask
but none have a white underside.
The Wood Frog is the most widely distributed amphibian in Canada and is found in every
province and territory. It is also found in the eastern and north-central United
Although found in tundra to the north and occasionally in grasslands in the west, the Wood
Frog is most commonly associated with moist woodlands and vernal woodland pools.
Wood Frogs are the earliest breeders in most of their range, often beginning to
call when their is still ice on the ponds in spring. The egg mass of up to 2,000
eggs is attached to submerged vegetation. Most of the egg masses in a population
will be laid within a few days and clustered together so their combined dark colouration
warms them and speeds hatching. The tadpoles transform after 44-85 days.
Wood Frogs are freeze tolerant and hibernate under logs or leaf litter on the forest
floor. Wood Frogs can change colour rapidly from very dark to very light. They will
darken when cold in order to absorb more heat.
Wood Frogs are very widespread and abundant.