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Canadian Herpetological Society





Société d'herpétologie du Canada



Anaxyrus hemiophrys

formerly Bufo hemiophrys

Canadian Toad / Crapaud du Canada


Canadian Toad

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, or "boss" between the eyes. The parotoid 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 Eastern 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 Boreal Toad in Alberta. It can be distinguished from these species based on the presence and shape of the cranial crests and parotoid glands. The Eastern American Toad has elongate parotoid glands which do not touch the cranial crest. The Great Plains Toad has cranial crests which diverge between the eyes. The Boreal Toad has no cranial crests. Spadefoots also have digging tubercles on their hindfeet, but unlike toads they have neither cranial crests nor parotoid 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.