Northwestern Salamander
Ambystoma gracile
Northwestern Salamander
Ambystoma gracile
The Northwestern Salamander is a large salamander that can reach a total body length of up to 24 cm. They are typically a uniform dark black, but may also be grey or black, and may have light flecking on their back. The belly is usually light cream-brown and may have yellow or white speckling. They have large, dark eyes that protrude from a broad head. They are easily identified by their large behind the eyes, enlarged glandular ridge along the top of a laterally compressed tail, and 10-12 prominent . Some populations near permanent ponds or lakes that do not freeze solid in the winter will display , where individuals will retain aquatic larval characteristics into adulthood and remain aquatic. Neotenic individuals will typically grow larger than their terrestrial counterparts. Northwestern Salamander larvae are generally brown, black, green with light mottling and have feathery gills behind the head, front and back legs, and long tail fins.
Listen to the Indigenous words for “salamander” here!
The Northwestern Salamander does not closely resemble any other species in British Columbia, but if unsure, it can be identified by its uniform dark colour, large parotid glands, and laterally compressed tail.
The Northwestern Salamander is found in North America west of the Coast and Cascade mountains from southeast Alaska, through British Columbia, and south to northwestern California. In British Columbia they are primarily found in the southwest corner of the province along the mainland coast and on Vancouver Island. There are two recognized subspecies in British Columbia:
The Brown Salamander (Ambystoma gracile gracile) found on the south coast and Vancouver Islands,
The British Columbia Salamander (Ambystoma gracile decorticatum) found north of Bella Coola.
Northwestern Salamanders are reliant on both forests and permanent water bodies. They are most often associated with mature forests that remain cool and moist and are in close proximity to breeding sites. They are highly fossorial (often burrowing) when terrestrial and burrowing sites such as logs, rocks, large debris, and old mammal burrows are important microhabitat features. Northwestern Salamanders prefer fish-free aquatic habitats for breeding and will breed in permanent and semi-permanent lakes, slow-flowing streams, or wetlands. Mammal burrows, root cavities, or rock crevices that extend below the frost line are important features for overwintering habitat.
Northwestern Salamanders breed in the spring, with the timing of breeding being dependent on elevation and latitude. They will gather at aquatic breeding sites where males will court females by rubbing their chin along the female’s head. If the courtship is successful, he will deposit a sperm sac (spermatophore) that the female will then pick up with her . After fertilization, the female will attach a grapefruit-sized egg mass containing up to 270 eggs to aquatic vegetation or detritus at a depth of 5-20 cm. Hatching occurs anywhere from 2-8 weeks depending on conditions, and larvae metamorphose into terrestrial individuals in 1-2 years, although some individuals will remain in a neotenic form. Sexual maturity is typically reached 1 year after metamorphosis. The lifespan of Northwestern Salamanders appears to be at least 5 years.
Northwestern Salamanders, both adults and juveniles, are carnivorous and will eat most terrestrial invertebrates including insects, spiders, worms, and slugs. Larvae largely feed on aquatic insects, zooplankton, and tadpoles.
Northwestern Salamanders are very elusive, but existing observations suggest that they are doing well as they occur in a variety of habitats and are successful in avoiding many predators. However, habitat loss and fragmentation, particularly from logging and urban development, may threaten this species. They may also suffer significant mortality on roads, where roadways bisect migration routes between overwintering and breeding habitat. Introductions of predatory fish can extirpate, or have significant impacts on larval stages. However, some reports of Northwestern Salamander larvae coexisting with introduced fish exist. More research is needed on coexistence of this species with predatory fish.
Description
The Northwestern Salamander is a large salamander that can reach a total body length of up to 24 cm. They are typically a uniform dark black, but may also be grey or black, and may have light flecking on their back. The belly is usually light cream-brown and may have yellow or white speckling. They have large, dark eyes that protrude from a broad head. They are easily identified by their large behind the eyes, enlarged glandular ridge along the top of a laterally compressed tail, and 10-12 prominent . Some populations near permanent ponds or lakes that do not freeze solid in the winter will display , where individuals will retain aquatic larval characteristics into adulthood and remain aquatic. Neotenic individuals will typically grow larger than their terrestrial counterparts. Northwestern Salamander larvae are generally brown, black, green with light mottling and have feathery gills behind the head, front and back legs, and long tail fins.
Listen to the Indigenous words for “salamander” here!
Similar Species
The Northwestern Salamander does not closely resemble any other species in British Columbia, but if unsure, it can be identified by its uniform dark colour, large parotid glands, and laterally compressed tail.
Distribution
The Northwestern Salamander is found in North America west of the Coast and Cascade mountains from southeast Alaska, through British Columbia, and south to northwestern California. In British Columbia they are primarily found in the southwest corner of the province along the mainland coast and on Vancouver Island. There are two recognized subspecies in British Columbia:
The Brown Salamander (Ambystoma gracile gracile) found on the south coast and Vancouver Islands,
The British Columbia Salamander (Ambystoma gracile decorticatum) found north of Bella Coola.
Habitat
Northwestern Salamanders are reliant on both forests and permanent water bodies. They are most often associated with mature forests that remain cool and moist and are in close proximity to breeding sites. They are highly fossorial (often burrowing) when terrestrial and burrowing sites such as logs, rocks, large debris, and old mammal burrows are important microhabitat features. Northwestern Salamanders prefer fish-free aquatic habitats for breeding and will breed in permanent and semi-permanent lakes, slow-flowing streams, or wetlands. Mammal burrows, root cavities, or rock crevices that extend below the frost line are important features for overwintering habitat.
Reproduction
Northwestern Salamanders breed in the spring, with the timing of breeding being dependent on elevation and latitude. They will gather at aquatic breeding sites where males will court females by rubbing their chin along the female’s head. If the courtship is successful, he will deposit a sperm sac (spermatophore) that the female will then pick up with her . After fertilization, the female will attach a grapefruit-sized egg mass containing up to 270 eggs to aquatic vegetation or detritus at a depth of 5-20 cm. Hatching occurs anywhere from 2-8 weeks depending on conditions, and larvae metamorphose into terrestrial individuals in 1-2 years, although some individuals will remain in a neotenic form. Sexual maturity is typically reached 1 year after metamorphosis. The lifespan of Northwestern Salamanders appears to be at least 5 years.
Diet
Northwestern Salamanders, both adults and juveniles, are carnivorous and will eat most terrestrial invertebrates including insects, spiders, worms, and slugs. Larvae largely feed on aquatic insects, zooplankton, and tadpoles.
Threats
Northwestern Salamanders are very elusive, but existing observations suggest that they are doing well as they occur in a variety of habitats and are successful in avoiding many predators. However, habitat loss and fragmentation, particularly from logging and urban development, may threaten this species. They may also suffer significant mortality on roads, where roadways bisect migration routes between overwintering and breeding habitat. Introductions of predatory fish can extirpate, or have significant impacts on larval stages. However, some reports of Northwestern Salamander larvae coexisting with introduced fish exist. More research is needed on coexistence of this species with predatory fish.
Did You Know?
Northwestern Salamanders, like many other salamanders, secrete a poison from their body when threatened. However, the poison of the Northwestern Salamander not only tastes bad, but is strong enough to kill many of its predators like snakes and shrews. The poison is not particularly harmful to people, although it can cause mild skin irritation.
The Northwestern Salamander is one of the few native amphibians to British Columbia that are able to survive in areas where there have been introductions of predatory fish and Amercian Bullfrogs, likely because of their poisonous secretions.
The egg masses of Northwestern Salamanders are unique amongst the salamanders in British Columbia in that they form a symbiotic relationship with green algae inside the jelly layer of the egg mass. The egg mass turns green and slimy, and allows for rough estimates of how long the eggs have been deposited for.