Western toad (Anaxyrus boreas)

Appearance and characteristics

Adult Western toads typically measure from about 5.6 cm up to around 13 cm in body length. They have stout bodies, dry, warty skin and often display a light dorsal stripe. Key features include large parotoid (poison) glands behind the eyes and short limbs adapted for walking and short hops rather than long leaps.

Habitat and range

This toad occurs in a variety of environments in western Canada, the United States and parts of Mexico, from lowland meadows and forests to montane basins and subalpine areas. Breeding usually occurs in ponds, lakes, marshes or slow-moving streams; a typical regional depiction of distribution is available via a range map.

Life history and behavior

Western toads are mostly nocturnal and insectivorous, feeding on beetles, ants, moths and other invertebrates. Reproduction follows a seasonal cycle: adults congregate at breeding sites to lay eggs, which develop into aquatic tadpoles before metamorphosing into terrestrial juvenile toads. Their life history makes them tied to both aquatic and upland habitats.

Conservation and threats

Populations show regional variability. Some groups remain common while others have declined. Major pressures include habitat loss, road mortality, introduction of predatory fish to breeding waters, and emerging amphibian diseases such as chytridiomycosis. Conservation actions commonly focus on habitat protection, monitoring, and reducing threats at breeding sites.

Ecological role and notable facts

• As insect predators, Western toads help control pest populations and form part of food webs.
• Their skin secretes toxins that deter many predators; nevertheless some animals and parasites specialize on them.
• Because they require both aquatic and terrestrial environments, they can serve as indicators of ecosystem health.

Understanding local population trends and protecting both breeding wetlands and upland foraging areas are central to maintaining healthy Western toad populations across their range.