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Rough-skinned Newt

Taricha granulosa

Introduction

The term newt and salamander are often used interchangeably. For clarification all newts are salamanders that belonging to a subfamily called Pleurodelinae of the family Salamandridae. 

The Roughed-skinned Newt is a specific type of salamander that lives around Hotel Lake. It is one of our Hotel Lake neighbours that is both beautiful and innocuous - provided you know and respect how toxic it can be.

Since the inception of this website, we have had several requests from our subscribers to create a page on the Roughed-skinned Newt. While larger animals such as bears, cougars, Rosevelt Elk and the like have grabbed our attention, it is now time to say hello to the Roughed-skinned Newt.

Range

Rough-skinned Newts occur throughout the West Coast of British Columbia. Their range extends north and south along the West Coast from southern Alaska to central California.

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Characteristics - Anatomy

Although most individuals are much smaller, Rough-skinned Newts may grow as large as 22 cm in total length, much larger than most salamanders. Males and females look alike with males being slightly larger.  They are blackish brown to greyish olive green on their upper side with a bright yellow or orange belly and 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.

They have small eyes with yellow irises and orange lower eyelids. 

 

Their skin is granular (rough, covered with what looks like tiny warts) and relatively dry compared to other salamanders, except during mating season when the male’s skin appears smooth and slimy They have webbed feet and the tail is laterally compressed (paddle shaped) near the end with a prominent ridge. The rear legs of breeding males are enlarged.

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Habitat 

Adult and juvenile Rough-skinned Newts primarily inhabit forested areas within close proximity to their aquatic breeding sites. They need damp conditions to keep their skin moist; logs, rocks and other cover objects provide important microhabitats.

Adults spend extended periods of time in aquatic habitat during the spring.  Some individuals are known to spend their entire life in the water.  They breed in wetlands, ponds, pools, sloughs, slow streams and other shallow aquatic habitats, and their larvae live in these aquatic habitats.

 

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. On the other hand newts that inhabit shallow or seasonal wetlands will hibernate in underground cavities or under cover such as rotting logs.

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Life Cycle

Rough-skinned newts thrive in aquatic and semi-aquatic habitats. They can be found in various wooded and open valley areas that include aquatic breeding habitat, such as lakes, reservoirs, ponds, and stream pools or backwaters.

They are cold-blooded and begin their life in water as aquatic gill-breathing larvae. Later they move to land and their bright orange skin fades to green. Unlike other salamanders that breath through their skin for the duration of their life, Rough-skinned newts develop lungs as they grow.

 

They generally spend most of their lives on land, but in some areas male adult newts may remain in aquatic water bodies throughout the year or during dry seasons.

 

Individuals reach sexual maturity after four to five years and they are known to live for 12 years or more.

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Male Rough-skinned Newts migrate first, leaving upland habitats and moving to their breeding sites on warm, rainy nights in the spring or fall; females follow soon after. These migrations may involve distances of several hundred metres towards their aquatic breeding site. The skin of the male becomes rather smooth and wet-looking and their rounded tail becomes paddle-shaped.

In spring, females mate; up to a dozen males might “mob” a single female in a “mating ball” for up to an hour. Eventually, males deposit a spermatophore into the water, and the female collects many of them to fertilize her eggs.

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The female lays single eggs and is believed to be the only newt that hides its eggs within vegetation, submerged twigs or leaves. The ova are small (0.7 inches diameter). The ovum (egg) is tan above and cream below with a thin layer of jelly surrounding the capsule. Newt eggs hatch 3 to 4 weeks after being laid.

 

The larvae are a tan-colour with dark flecks and a salmon-pink belly and have ragged or feathery looking gills behind the head. They undergo metamorphosis into terrestrial juveniles in the late summer or the summer of the following year.  As they transition, tiny yellow-white spots  appear running along the sides of their body and they develop front legs and back legs and a tail fin.

After about three months, with autumn approaching, those, that have developed into terrestrial juveniles, make their first migration onto land and find their way into upland forests where they remain for a few years before migrating back to their aquatic birthplace.

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Foraging and Diet

When on land, these newts forage for invertebrates on the forest floor. They prefer dark damp areas with ponds, fallen logs and leaves; here they eat insects, slugs, worms and snails.

When in an aquatic environment adults prey on a variety of soft-bodied, slow-moving aquatic and terrestrial invertebrates, such as crustaceans (fairy shrimp), insects, spiders, slugs, small crustaceans and worms, leeches, freshwater sponges as well as amphibian eggs and larvae.  They hunt by approaching slowly and then quickly sucking prey into mouth equipped with small teeth and tongue.

 

Rough-skinned Newt larvae start feeding on zooplankton (tiny animals suspended in the water), single-celled organisms called protozoans found on plants, rocks, and other objects in their habitat. They also eat small crustaceans and even other smaller newt larvae.

 

 In backyard ponds they will eat small fish but can also fall prey to bigger fish.

Endangered or Invasive Species

These amphibians occur in dense populations, have a low vulnerability to predators and can occupy a variety of habitats, which contribute to the Rough-skinned Newts being one of the most common amphibians in coastal B.C. These amphibians are Yellow listed in B.C. and are managed at the ecosystem level.

 

The Rough-skinned Newt is protected under the British Columbia Wildlife Act. 

How can Humans Help and Respect

Humans should be respectful and cautious of this little creature. Humans are, sadly, the biggest threat to Rough-skinned Newts. Many are killed by cars, as they cross roads in their attempt to travel between the forest and water sources. Destruction of their habitat via deforestation and development also reduce their numbers.

 

This advice from the BC Frogwatch Program: “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.”

 

So if you see a Rough-skinned Newt, give it room to exist;  If you admire them from a distance, you will be rewarded with a sense of peace and a better connection with nature and likely find happiness in the knowledge that they are eating the slugs in your yard!  They are long standing members of our shared ecosystem.While migrating on land, newts are easy to spot, even during the day. They move slowly and are often out in the open.  They are especially vulnerable to being hit by vehicles on roads.

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Activities or Behaviour that might cause harm to humans

Rough-skinned Newts enjoy the freedom to be very active in the open and during daytime. This is because they have a built-in protection. On their bodies they have high levels of a powerful neurotoxintoxin poison called tetrodotoxin (TTX) which causes paralysis and death (also found in pufferfish and blue-ringed octopus).

 

When threatened, these newts arch their head and tail in a defensive posture called the “unken reflex” which shows off their bright-yellow underside. This posture and the bright-yellow colouration are accompanied by the release of TTX which has a sticky feeling to the skin. At the same time an associated slightly acidic-acrid-foul smell radiates from the newt, which acts as an additional warning for bird and mammalian predators to stay away.

 

The only predators that can survive eating a Rough-skinned Newt are garter snakes that live in the same geographic area and that have developed an immunity to the toxin. Garter snakes outside of this newt’s home ranges have no such immunity.

Research into Rough-skinned Newt’s and TTX is ongoing. It is not yet understood how newts create TTX although recent studies have now shown that bacteria living on rough-skinned newts produces TTX.

Below is a diagram from a study titled: An Overview of the Anatomical Distribution of Tetrodotoxin in Animals, by: Daria I. Melnikova and Timur You Magarlamov, available at:  https://www.mdpi.com/2072-6651/16/4/186

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Human awareness of the dangers of TTX is of great importance.

 

Why? Because tetrodotoxin (TTX) is one of the most dangerous toxins known to man. It acts on the nervous system and can lead to muscle paralysis and death.

 

Neither garter snakes or newts are venomous, meaning that they won’t poison you by biting you. Not only will these newts not bite humans but they are actually pretty friendly. And, rather insidiously, a glimpse at the pretty yellow-orange undersides can make them tempting for children who may spontaneously pick them up before we adults notice.

While newts are considered to be the most poisonous amphibian in B.C., The toxin that is secreted onto the newt’s skin isn't absorbed through human skin so humans should be able to handle the newts safely with bare hands but certain precautions are absolutely necessary which will become evident as you read further.

 

The toxin TTX attacks humans through the digestive tract, or a break in the skin, or via any mucous membrane such as the eyes. This means it should be safe to handle newts provided the handling is followed by a thorough washing of hands and any other skin-newt contact areas immediately after handling. It is very important to avoid touching your eyes, mouth, nose or any damaged or irritated skin until after a thorough cleaning.

There have been reports of human skin irritations after handling newts, particularly if the eyes are touched after handling the animal without washing hands. There are also many reports of long term skin irritation and pain associated with handling newts. Toxicity in humans is generally experienced only if the newt is ingested and there are incredible cases of humans eating these newts with fatal outcomes. We found this example: “On a dare, a 29-year-old man in Oregon swallowed a 20-cm rough-skinned newt and died in July, 1979.”

 

It goes without saying that children must be supervised at all times when they're around newts..

There is certainly enough poison in a newt to kill a child. 

Symptom onset from TTX exposure by newt ingestion is typically acute and includes a burning sensation and then numbness and tingling on the lips and tongue ingestion, followed by lightheadedness and paresthesias of face and extremities. The patient may experience headache, nausea, vomiting, diarrhea, and ataxia.

Caution

Studies have shown that in certain areas, for example, parts of Vancouver Island, Rough-skinned Newts have little, or no TTX. Without going into specifics, scientific studies speculate that evolutionary forces may be involved: “This apparent matching of defence and exploitative ability among populations is a predicted outcome of an evolutionary arms race between predator and prey (Brodie and Brodie, 1990)”. 

 

It is very important to understand that while the aforementioned anomalies do exist, they are exceptions; here on the Sunshine Coast and throughout the balance of its natural range, Rough-skinned Newts generally carry the highly toxic TTX.

 

Emergency

If you have a possible poisoning emergency, call your local poison control centre immediately:     1-844-764-7669.    You can also Visit infopoison.ca  

 

If the person is unconscious, not breathing, or having a seizure, call 9-1-1.

 

The toxin in a newt can kill a pet within four to six hours of ingestion. Heaven forbid that your dog or pet they should snap-up a newt and give it a chomp, but that may be exactly what a dog would do.  So if you find your pet eating or even playing with a newt, rush your pet to the vet.

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References

 

Canadian Herpetological Society:  https://canadianherpetology.ca/species/species_page.html?cname=Rough-skinned Newt

 

Sierra Club of BC:   https://sierraclub.bc.ca/rough-skinned-newt/

 

BC Conservation Data Centre: Species Summary:

https://a100.gov.bc.ca/pub/eswp/speciesSummary.do?id=14222

 

E-FAUNA BC: Electronic Atlas of the Wildlife of BC:     https://linnet.geog.ubc.ca/efauna/Atlas/Atlas.aspx?sciname=Taricha granulosa

 

BC Wildlife Federation:   https://bcwfbogblog.com/2013/05/17/species-profile-rough-skinned-newt/

 

Fraser Valley Conservancy, poster of newts and salamanders on BC west coast:   https://fraservalleyconservancy.ca/wp-content/uploads/2018/03/Salamander-ID-hi-res.pdf

 

 

Washington Department of Fish and Wildlife:  https://wdfw.wa.gov/species-habitats/species/taricha-granulosa#desc-range

 

Go Hiking:  https://gohiking.ca/animals/amphibians/salamanders/rough-skin-newt/

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