Description
This relatively small toad is either brown to grey-green or
reddish with reddish warts surrounded by black spots. There is a light
line down the centre of the back and the belly is pale with grey spots.
It is distinguished by cranial crests which
fuse to form a hump between the eyes. The parotid
glands are large and oval or kidney shaped and meet the cranial crests.
Two prominent tubercles on its hind feet are
used for burrowing. Maximum adult size is only 7 cm.
Call
The call of the Canadian Toad is a brief harsh trill shorter
than that of the American Toad but longer than
that of the Gray Treefrog. It is repeated every
15-20 seconds. Males may call at temperatures as low as 5oC.
Confusing Species
The Canadian Toad overlaps with the American
Toad in central Manitoba, the Great Plains Toad
on the extreme southern prairie provinces and the Western
Toad in Alberta. It can be distinguished from these species based on
the presence and shape of the cranial crests and parotid glands. The American
Toad has elongate parotid glands which do not touch the cranial crest.
The Great Plains Toad has cranial crests which diverge between the eyes.
The Western Toad has no cranial crests. Spadefoots also have digging tubercles
on their hindfeet, but unlike toads they have neither cranial crests nor
parotid glands.
Distribution
The Canadian Toad is widely distributed through the eastern
half of Alberta, most of Saskatchewan and the western half of Manitoba.
It reaches its northern extent in the Northwest Territories near Fort Smith.
In the United States it is restricted to Montana, the Dakotas and Minnesota,
with a disjunct population in Wyoming. This is one of the few amphibians
with most of its range in Canada.
Habitat
Canadian Toads are found near ponds, lakes and potholes throughout
the prairies and aspen parkland and more sparsely in boreal forests. Breeding
occurs in the shallow margins of permanent water or in temporary ponds
and puddles.
Reproduction
Breeding occurs from May to July. Up to 7000 eggs are laid in
a single strand and hatch three to twelve days later. Juvenile toads emerge
six to seven weeks later.
Natural history
The Canadian Toad may be active during the day or night depending
on temperatures. It burrows underground to avoid extreme heat and also
hibernates below the frost line. Worms, beetles and ants are among the
foods eaten. Although highly terrestrial it will take to water to avoid
capture.
Conservation Concerns
The Canadian Toad has declined in southern Alberta and parts
of Manitoba. Possible threats include wetland drainage and drought.
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