Northwestern salamander • Ambystoma gracile
Left: an adult northwestern salamander photographed by Jeremiah Kennedy. Right: northwestern salamander egg masses found in boggy areas on Gosling Island (top, photo by Wiebe Nijland) and Calvert Island (bottom, photo by Elizabeth Bailey). The bottom mass appears to be further along in development, with more larval-shaped forms visible in the jelly tinged green by algae. Egg mass identifications confirmed by John Reynolds and Kristiina Ovaska.
Identification
This large salamander (to 24 cm long) is usually dark brown, but can vary to grey or black and may be flecked with cream or yellow. Its broad, rounded head has large and protruding dark eyes behind which swell large parotoid glands, which secrete a mild poison as a defense response. Similar glands are found on the top ridge of the tail. The tail is vertically compressed, and rib-like furrows (costal grooves) run along the sides of the body.
The aquatic larvae have large feathery gills, a light or translucent tail, and are dark with light mottling on top and light underneath. Some adults retain gills and other larval characteristics (known as neoteny), and remain in aquatic habitats their whole life. These aquatic adults are common, and occur more often at higher elevations.
Northwestern salamander eggs are laid in firm masses that are orange- to grapefruit-sized, and contain up to 270 eggs each. Each egg is embedded in its own jelly layer, with an additional layer of jelly encompassing the entire mass, giving it a smooth to slightly bumpy or wavy surface. Newly laid eggs are tan on top and cream or pale gold beneath; older egg masses (the eggs take 2-8 weeks to hatch) are often tinged green by algae growing in the inner jelly layer of individual eggs. Egg masses are laid below the surface of fresh water, attached to stems or small sticks.
Click here for more images of this species at various stages of development.
Habitat & Range
The northwestern salamander inhabits ponds, lake edges, slow-moving streams, ditches, and other wetlands in the spring, when individuals gather to breed. During the rest of the year it is relatively inactive and elusive, commonly hiding out in underground burrows (such as ones dug by mammals) or under rocks and logs, in cool and moist forests. It also inhabits grasslands, woodlands, and other moist terrestrial habitats. Larvae and neotenes (the aquatic adults that display neoteny) remain in unfrozen ponds and lakes through winter.
This species is found along the west coast of North America from the very tip of southern Alaska to northern California, from sea level to high elevations in the Coast and Cascade Mountains.
Similar Species
The other salamanders found on the Central Coast are the long-toed salamander (Ambystoma marodactylum) and the roughskin newt (Taricha granulosa). The former is easily differentiated by the yellow to green stripe, which can be patchy and incomplete, running along its back and tail; the latter by it's bright orange or yellow undersides which it exposes when threatened by potential predators.
Intriguing Info
The poison that this species secretes can be a minor skin irritant to people, but to small predators like snakes, birds, fish, and shrews, it can be deadly. Unlike most other native amphibians, the northwestern salamander is able to live in habitats where invasive predatory fish and bullfrogs have established populations, likely because of the strong effects of its poisons on predators.
This species appears to have a large and stable population.
iNaturalist
https://www.inaturalist.org/taxa/26747-Ambystoma-gracile
This large salamander (to 24 cm long) is usually dark brown, but can vary to grey or black and may be flecked with cream or yellow. Its broad, rounded head has large and protruding dark eyes behind which swell large parotoid glands, which secrete a mild poison as a defense response. Similar glands are found on the top ridge of the tail. The tail is vertically compressed, and rib-like furrows (costal grooves) run along the sides of the body.
The aquatic larvae have large feathery gills, a light or translucent tail, and are dark with light mottling on top and light underneath. Some adults retain gills and other larval characteristics (known as neoteny), and remain in aquatic habitats their whole life. These aquatic adults are common, and occur more often at higher elevations.
Northwestern salamander eggs are laid in firm masses that are orange- to grapefruit-sized, and contain up to 270 eggs each. Each egg is embedded in its own jelly layer, with an additional layer of jelly encompassing the entire mass, giving it a smooth to slightly bumpy or wavy surface. Newly laid eggs are tan on top and cream or pale gold beneath; older egg masses (the eggs take 2-8 weeks to hatch) are often tinged green by algae growing in the inner jelly layer of individual eggs. Egg masses are laid below the surface of fresh water, attached to stems or small sticks.
Click here for more images of this species at various stages of development.
Habitat & Range
The northwestern salamander inhabits ponds, lake edges, slow-moving streams, ditches, and other wetlands in the spring, when individuals gather to breed. During the rest of the year it is relatively inactive and elusive, commonly hiding out in underground burrows (such as ones dug by mammals) or under rocks and logs, in cool and moist forests. It also inhabits grasslands, woodlands, and other moist terrestrial habitats. Larvae and neotenes (the aquatic adults that display neoteny) remain in unfrozen ponds and lakes through winter.
This species is found along the west coast of North America from the very tip of southern Alaska to northern California, from sea level to high elevations in the Coast and Cascade Mountains.
Similar Species
The other salamanders found on the Central Coast are the long-toed salamander (Ambystoma marodactylum) and the roughskin newt (Taricha granulosa). The former is easily differentiated by the yellow to green stripe, which can be patchy and incomplete, running along its back and tail; the latter by it's bright orange or yellow undersides which it exposes when threatened by potential predators.
Intriguing Info
The poison that this species secretes can be a minor skin irritant to people, but to small predators like snakes, birds, fish, and shrews, it can be deadly. Unlike most other native amphibians, the northwestern salamander is able to live in habitats where invasive predatory fish and bullfrogs have established populations, likely because of the strong effects of its poisons on predators.
This species appears to have a large and stable population.
iNaturalist
https://www.inaturalist.org/taxa/26747-Ambystoma-gracile
References
Identification Guide for Eggs of pond-breeding amphibians of the North Shore. FrogWatch in BC Atlas. Community Mapping Network British Columbia. Accessed 28/01/2016.
IUCN SSC Amphibian Specialist Group. (2015). Ambystoma gracile. The IUCN Red List of Threatened Species. Accessed 28/01/2016.
Northwestern Salamander. B.C. Frogwatch Program. Ministry of Environment, Province of British Columbia. Accessed 28/01/2016.
Rockney, H. and Wu, K. (2015). Northwestern Salamander. Burke Blog. Burke Museum, Seattle, WA. Accessed 28/010/2016.
Authors and editors of page
Kelly Fretwell (2016).
Identification Guide for Eggs of pond-breeding amphibians of the North Shore. FrogWatch in BC Atlas. Community Mapping Network British Columbia. Accessed 28/01/2016.
IUCN SSC Amphibian Specialist Group. (2015). Ambystoma gracile. The IUCN Red List of Threatened Species. Accessed 28/01/2016.
Northwestern Salamander. B.C. Frogwatch Program. Ministry of Environment, Province of British Columbia. Accessed 28/01/2016.
Rockney, H. and Wu, K. (2015). Northwestern Salamander. Burke Blog. Burke Museum, Seattle, WA. Accessed 28/010/2016.
Authors and editors of page
Kelly Fretwell (2016).