Canadian Toad

Last Review/Updated: May 30, 2002

Bufo hemiophrys

Description

Alberta's smallest toad, the Canadian (or Dakota) toad ranges in length from 37-75 mm. It tends to be brown or grey-green in colour with brownish-red warts. There is also a rusty, or red-coloured phase. The belly is whitish and spotted with grey. Along with the spots on the belly, the distinguishing characteristics of this toad are the cranial crests which are either parallel or joined to form a raised bump between the eyes. In the great plains toad, the crests are always diverging behind the eyes. The Canadian Toad also has two prominent tubercles on its hind feet to aid it in burrowing.

Natural History

In Alberta, the Canadian toad is generally active from April to September. It is one of the most terrestrial of Canada's amphibians, sometimes found far from water. Because of its mottled earthy colour, it can blend in well with its surroundings. Generally, it is active during the day and burrows into the ground at night. However, if the evening is warm enough the Canadian toad is also nocturnal. It feeds on a variety of worms, beetles, and ants. The Canadian toad is currently on the Red List in the Status of Alberta Wildlife. Dramatic declines in its parkland distribution may indicate that it is in serious trouble.

Breeding

After coming out of hibernation, the toads migrate to breeding ponds in the spring. Breeding can range from May to July. Males can be active and call at unusually low temperatures (5°C). The call is a soft trill which lasts a few seconds. Breeding generally takes place in shallow areas of lakes, ponds or even temporary bodies of water. A female lays a single strand of eggs numbering up to 7000 eggs. Depending upon the temperature of the water, the eggs will hatch 3-12 days later.

Larvae

The tadpoles are tiny and black. Six or seven weeks after hatching the tadpoles transform into juvenile toads.

Distribution

The Canadian toad has one of the widest distributions in the province. It ranges from the Bow River north into the Northwest Territories. Preferred habitat is aspen parkland up to elevations of roughly 1200 m. Although widely distributed, the Canadian toad is generally found in river valleys or along the margins of lakes with sandy margins. In central Alberta it overlaps with the distribution of the western toad.

Monitoring

Canadian toads are diurnal, and are found at highest densities during the breeding season. In the spring, adults will congregate at breeding ponds and begin calling.