Ministry of Environment
|Common Name:||Roughskin Newt|
|Scientific Name:||Taricha granulosa|
Roughskin Newts have relatively grainy and dry skin compared to other salamanders (leading to their name). They are also fairly large for a salamander, and adults can reach a maximum length of almost 22 centimetres from the tip of the nose to the end of the tail. They are dark brown to grey on top and, unlike any other salamander in B.C., they are bright yellow or orange below. This colour serves as a warning to would-be predators. When disturbed, the newt will curve its head, neck and tail upwards to display this bright colouring.
Roughskin Newts can appear quite chubby compared to other salamanders, partly because they lack the costal grooves (indents along the body that look like ribs) that are present in most other salamander species. During the breeding season, males can enter an aquatic phase where their skin becomes relatively smooth, and their normally rounded tail becomes flattened like a paddle.
Newt larvae are aquatic with ragged looking gills. Their body and limbs are less stocky looking than those of other salamander larvae within their range. Newt larvae are tan-coloured with black flecks, and a pink or salmon abdomen. A key feature of older larvae is the one or two rows of tiny white spots that run along each side of the body.
Roughskin Newts live in aquatic and terrestrial habitats. They are most common in forested environments, living in and under rotting logs. Like most amphibians, newts become more active at the surface when it rains, but unlike other salamander species they will venture out during the day. Newts migrate back to ponds, lakes, wetlands, or slow moving streams in the spring to breed, laying their eggs along shallow, vegetated shorelines. Some adults live in lakes or ponds throughout the summer or year round, and can often be seen swimming near the surface. After the breeding season, others return to forests to forage until the fall.
Roughskin Newts migrate to breeding ponds in spring. Like all native salamander species, newts have internal fertilization whereby the male releases a sperm packet that the female picks up with her cloaca. However, unlike most amphibians, newts lay single eggs attached to the stems of vegetation and scattered throughout the breeding habitat. This egg scattering may be an advantage, because newts eat amphibian eggs (including those of other newts) and the dense concentrations of adults that can occur in some ponds and lakes would quickly deplete the pond of young newts. Newt eggs hatch 3 to 4 weeks after being laid, and the larvae metamorphose into the terrestrial form in the summer of either the first or second year depending on the local climate. The newly metamorphosed newts head into upland forests, not returning to the pond to breed until a few years later. Roughskin Newts may live as long as 12 years.
Both adult and larval Roughskin Newts are carnivores. Adult newts eat a variety of organisms, including insects, slugs, worms, and even amphibian eggs and larvae. Newt larvae feast upon a variety of aquatic invertebrates and zooplankton (tiny animals suspended in the water).
Newts can be quite poisonous and are thus avoided by most predators. This is why these salamanders are able to routinely forage during the day. Many dead birds and fish have been found with Roughskin Newts in their stomachs, suggesting that eating a newt is a mistake these predators only make once. The Common Garter Snake, however, is apparently unaffected by the newt’s poison and is one of its major predators.
Roughskin Newts occur along the Pacific Coast as far north as the Alaska Panhandle and south to California, and from sea level to 2700 metres. Within B.C. they can be found along the west coast of the mainland, on some Gulf Islands, and throughout Vancouver Island.
Newts can be found in some ponds and lakes throughout the year. Terrestrial forms return to aquatic habitats during the breeding season, in early spring. Larvae are usually present in lakes and ponds in summer, but may occur year round at higher elevations where transformation can be delayed by cold temperatures. Outside of the breeding season juvenile and adult newts are usually found in upland forests, where they spend most of their time under logs and leaf litter, or in the burrows of other animals. However, newts can be active both day and night because their toxic skin reduces the risk of predation. Newts are inactive in winter, seeking refuge underground or under logs and debris where conditions remain moist and do not freeze.
Roughskin Newts are one of the most common amphibians in coastal B.C. owing to the fact that they can occur in dense concentrations, are less vulnerable to predators, and can occupy a variety of habitats. These amphibians are Yellow listed in B.C. and are managed at the ecosystem level. The Roughskin Newt is protected under the British Columbia Wildlife Act.
You can help by learning more about these salamanders and other amphibians, and telling others about them. You can find out more about ways to protect habitat through programs such as Naturescape, Wetlandkeepers, and Wild BC. Be an ambassador for these salamanders in council meetings and other planning meetings! You can also help biologists learn more about the range, distribution, and habits of these and other amphibians by joining B.C. Frogwatch and observing salamander populations near you. The more we learn about salamanders in general, the better we can help protect them.
- The Roughskin Newt is the most poisonous amphibian in the Pacific Northwest. It contains enough poison to kill 25,000 mice.
- The poison that the Roughskin Newt produces is similar to that created by the puffer-fish (a tetrodotoxin). The level of toxicity varies in different parts of the newt’s range.
- The Garter Snake has evolved a resistance to the lethal poison in the skin of Roughskin Newts. In the arms race between predator and prey, newts are constantly trying to become too toxic for snakes to eat. Scientists found that individual snakes assess their own resistance relative to newt toxicity when they attempt to eat a newt, and reject prey too toxic to consume. Newts were able to survive attacks and attempted ingestion by snakes that sometimes lasted over 50 minutes!
- For some unknown reason, a high proportion of male newts on Vancouver Island remain aquatic year round, while the females are largely terrestrial as they are throughout the rest of their range.
Photo © Wally Edwards. No reproduction or distribution without permission.