|
Canadian Herpetological Society Société d'Herpétologie du Canada |
|---|
.jpg)
Rough-skinned Newt
Taricha granulosa
Family: Salamandridae
COSEWIC status:- Not Assessed
- No Status
- Least Concern
Description
Rough-skinned Newts are heavy-bodied and have granular skin that is relatively dry compared to other salamanders. They are brown to olive green on top with a bright yellow or orange belly. This species lacks the costal grooves that are present on most other Canadian salamanders and the tail is laterally compressed near the end with a prominent ridge. The rear legs of breeding males are enlarged. Aquatic larvae have feathery gills behind the head, legs (both front and back) and a tail fin and are tan to brown with two rows of yellow spots along the sides. Rough-skinned Newts can grow up to 22 cm in total length, though most individuals are much smaller than this.
Similar Species
Rough-skinned Newts are the only salamanders in B.C. that lack costal groves and have dry, granular skin and a bright yellow belly.
Distribution
Click for larger image
In Canada, Rough-skinned Newts occur throughout the West Coast of British Columbia. Its range extends along the West Coast from southern Alaska to central California.
Habitat
Rough-skinned Newts breed in wetlands, ponds, pools, sloughs, slow streams and other shallow aquatic habitats, and the larvae live in these aquatic habitats. Adults and juveniles primarily inhabit forested areas within close proximity to these breeding sites, although adults spend extended periods of time in aquatic habitat during the spring and some individuals spend their entire life in the water. Logs, rocks and other cover objects provide important microhabitats for terrestrial adults and juveniles. In large bodies of water that are permanent, newts often spend the winter in the water and may remain active through much of the winter. Individuals that inhabit shallow or seasonal wetlands hibernate in terrestrial habitats in underground cavities or under cover such as rotting logs.
Biology
Rough-skinned Newts migrate to their breeding sites on warm, rainy nights in the spring. Females lay eggs singly throughout the breeding habitat, which they attach to aquatic vegetation or submerged leaves. The eggs hatch in three to four weeks and the larvae undergo metamorphosis into terrestrial juveniles in the late summer or the summer of the following year. Individuals reach sexual maturity after four to five years and the can live for over 12 years. Adult and juvenile newts prey on a variety of aquatic and terrestrial invertebrates, such as insects, slugs, small crustaceans and worms, as well as amphibian eggs and larvae. Larvae forage for protozoans, larval insects and small crustaceans, while terrestrial newts forage for invertebrates on the forest floor. Rough-skinned newts are the most poisonous amphibian in B.C. They produce a powerful neurotoxin, which is a very effective defence against bird and mammalian predators. When threatened, individuals will raise the head and the tail, showing off the bright yellow bellow as a warning of their toxicity.
Threats
The destruction of forest and wetland habitats is the primary threat to this species in Canada, especially in area where human population densities are high. However, this species is widespread and remains abundant throughout most of its range. Pollution, such as herbicides, agricultural effluent and road salt can be detrimental to newts since toxins are easily absorbed though their skin. Climate change and introduced pathogens pose potentially serious future threats to Canadian salamanders.