A giant that barks
The Pacific Giant Salamander (Dicamptodon tenebrosus) is the largest terrestrial salamander in North America. Adults can reach a total length of 35 cm (14 inches). Its skin is smooth, with a mottled pattern of dark blotches on a lighter brown or copper-colored background. This salamander possesses a robust body, a broad head, and strong legs suited for its environment. Unusually for a salamander, it can produce sound. When threatened, it emits a croaking or barking noise by snapping its jaws.
Its Canadian range is extremely limited, confined to the Chilliwack River watershed and adjacent areas in southwestern British Columbia. This restricted area covers only about 250 square kilometers. The salamanders inhabit clear, cold, fast-flowing mountain streams with gravel or boulder beds, and also live in the damp forests alongside these waterways. Terrestrial adults are nocturnal foragers, emerging from beneath logs or rocks on rainy nights to hunt. Their diet is varied and includes insects, slugs, snails, and even small mammals like shrews and mice.
A life in two worlds
The life cycle of the Pacific Giant Salamander shows developmental plasticity. Females lay between 135 and 200 eggs under rocks or logs in streams. The aquatic larvae that hatch possess feathery external gills and a tail fin for swimming. They may spend several years in this larval stage before undergoing metamorphosis.
A characteristic of this species is its capacity for neoteny, where some individuals reach sexual maturity while retaining their larval, aquatic features, including gills. This phenomenon is particularly common in the British Columbia populations. These gilled adults, or neotenes, can grow even larger than their terrestrial counterparts and live their entire lives in the water. This adaptation allows the species to thrive in stable aquatic environments. The species is considered threatened in Canada due to its small, fragmented range and threats to its habitat from logging and development.