The Rough Skin Newt of the Pacific Northwest
Rough skin newts can be found on all parts of the B.C. Coast. They are also fairly large for a salamander, and adults can reach a maximum length of almost 22 cm from the tip of the nose to the end of the tail. They are dark brown to grey on top and they are bright yellow below, this color serves as a warning to predators. When disturbed, the newt will curve its body upwards to display this bright coloring, predators have learned to leave this guy alone.
Rough skin newts can appear quite chubby compared to other salamanders, partly because they lack the grooves along the body that are present in most other salamander species.
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 light brown colored with black flecks and a pink abdomen.
Rough skin newts live in both water and land 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. Cranberry Lake on Vancouver Island has a very large population of newts that return each year to mate. Some adults live in lakes or ponds year round and can often be seen swimming near the surface.
Newts migrate to breeding ponds in spring. Like all native salamander species, newts have internal fertilization where by the male releases a sperm packet that the female picks up. However, unlike most amphibians, newts lay single eggs attached to the stems of vegetation scattered throughout the breeding area. This egg scattering may be an advantage, because newts eat amphibian eggs, even other newt eggs and the large populations 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 morph into the adult form in the summer of either the first or second year depending on the local climate. The newly morphed newts head into upland forests, not returning to the pond to breed until a few years later. Newts may live as long as 12 years
Both adult and larval 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 zoo-plankton.
Newts are quite poisonous and are thus avoided by most predators. This is why these salamanders are able to venture out during the day. Many dead birds and fish have been found with Rough Skin 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.
The toxin that they produce is one of the most poisonous non protein substance known to scientists and similar to that found in puffer-fish that occasionally poison Japanese dinners. This very potent neuro-toxin acts by blocking sodium channels of excitable membranes. In other words, it blocks the conduction of nerve signals to the muscles. Blood vessels relax, leading to a sudden drop in blood pressure and shock. The toxin also blocks the signals from your brain that tell your heart to beat.
The rough skin newt is one of the most toxic animals known to science. One medical case involved a 29 year-old man who had been drinking heavily and swallowed a newt on a dare in Coos Bay, Oregon. Within a few hours he was dead despite hospital treatment. In another case, toxin from a newt entered a puncture wound on a scientist’s index finger and he suffered 30 minutes of numbness up the arm into the shoulder and some accompanying nausea and light headiness. Another involves a camper who made coffee in the morning and a newt had crawled into the coffee pot during the night, the camper was dead later that day.
Rough skin Newts occur along the southwest coast of BC and Washington, on some Gulf Islands and throughout Vancouver Island.