Western Toad
Last Review/Updated: May 30, 2002
Bufo boreas
Description
The largest of Alberta's toads, it can range from 55-125 mm in length. The western (or boreal) toad is usually green or brown with a light-coloured stripe down its back. The western toad can be distinguished from the other two true toads of Alberta by the lack of cranial crests between the eyes. The warts may be reddish-brown and surrounded by black.
Natural History
The western toad is active from April to September in Alberta. It is generally found near ponds, streams, or lakes. Although it is usually nocturnal, at higher elevations it can be diurnal. Unlike many toads, the western toad tends to walk rather than hop. Their diet consists mainly of worms, slugs, and insects. If threatened they will inflate themselves with air and raise up on their legs. The western toad is currently on the Green List in the Status of Alberta Wildlife and is considered not to be at risk. Populations are healthy and widespread.
Breeding
In April to June, western toads congregate to breed. Breeding ponds tend to be shallow, with cool water (less than 10°C) and sandy bottoms. The breeding ponds can be permanent or temporary. The males call with a quiet peeping sound to attract females. Eggs (1.5-1.7 mm in diameter) are laid in long strings, often entwined about submerged vegetation. A single female can produce thousands of eggs and within 3-12 days the eggs will hatch.
Larvae
The tadpoles begin life at about 10 mm in length and grow to 25-30 mm. The tadpoles are black on top and somewhat lighter underneath. Because of the great number of eggs laid, tadpole densities can be very high. By 6-8 weeks after hatching, the tadpoles transform into juvenile toads. It requires an additional 2-3 years for the young toads to become sexually mature.
DistributionThe western toad is found in western and central Alberta, primarily in boreal forest, subalpine and alpine environments. It is absent from the drier eastern and southern areas of the province. It can be found up to elevations of about 2300 m. The distribution in the northern region of the province may actually be more extensive than shown, but little work has been conducted in these areas. MonitoringWestern oads are primarily nocturnal, making them difficult to locate outside of the breeding season. In the spring, adults will congregate at breeding ponds and begin calling. |
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| Life Stage | April | May | June | July | August | Sept. |
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| Eggs Hatch |  |
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| Transformation |  |
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| or over winter | ||||||
