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Northwestern Salamander

Northwestern Salamander

Northwestern Salamander, Ambystoma gracile

Northwestern Salamander, Ambystoma gracile, can be found in and around ponds and wetlands and in the surrounding forest. It is secretive and shelters under decaying logs or in piles of sloughed-off bark, rodent burrows, or other moist hollows or crevices on the forest floor. This semi-aquatic salamander is large and robust with a total length up to about 250 mm (adult body length to 105 mm). A large distinct swelling containing poison glands (parotoid gland) is present on each cheek behind the eye. The colour is solid dark brown but is lighter in areas with concentrations of poison glands on cheeks, folds along the sides, and tail ridge. Occasionally individuals with light yellowish specks are encountered. Metamorphosed juveniles resemble adults. Eggs: The female lays a cluster of about 50 eggs in permanent water in early spring. The egg mass is firm, globular, and about the size of a grapefruit, attached to a submerged stem or twig. Individual eggs are about 2 mm in diameter and surrounded by jelly layers. Often, symbiotic algae grow in the jelly layer around the eggs, giving them a greenish tint. Aquatic larvae have bushy external gills on each side of the head. The gills look full and plume-like with side filaments along the entire length of the gill stalk. The head is large with a broad snout. Larvae are olive brown with large dark spots. Yellowish poison glands are evident in larger larvae, concentrated in parotoid glands and along the tail ridge. Larvae metamorphose into terrestrial forms in 1 or 2 years; they often over-winter and hence require permanent water. At some localities, the salamanders retain larval characteristics into adulthood and never leave water.

2016-12-13T10:36:09+00:00