Roughskin newts are small amphibians native to the Pacific Northwest – they can be found from California up to Alaska and when crossing the roads of our little island in the spring and autumn.
If you’ve ever spotted a live roughskin newt, it was most likely during one of those times. Perhaps you were out for a stroll or a bike ride and narrowly missed pancaking them to the road. These orange-bellied amphibians aren’t very fast on land and are often standing stock still when you come across them on the road, so you might have wondered, if it’s so dangerous for these little newts to be crossing the roads, then why do they do it?
Roughskin newts are amphibians, most of which are semi-aquatic creatures. A roughskin newt’s life cycle sees them moving between wetlands and forests, where they hibernate underneath decomposing woody debris for the winter. Roads sometimes run between these two habitats, and newts have to brave the concrete corridor in order to get from one habitat to the next. Issues like this are known as habitat fragmentation.
Roads aren’t the only kind of habitat fragmentation facing amphibians here. Critical wetlands on the island are a fraction of what they once were, and these days, the majority of amphibian breeding habitat is in the form of human made ponds on privately owned property. Although property boundaries are inconsequential to a newt, property owners are not; with some planning and implementation, these ponds have great potential to be wildlife-supporting habitats.
In order for a pond to be an ideal place for amphibians to thrive, it needs to have gently sloping sides, emergent vegetation, and for some species such as the roughskin newt, water year-round (some males stay in the pond all year). Gradually sloped sides allow emergent vegetation to grow, providing food for prey, shelter from predators, and a place for amphibians to lay eggs. Though it lacks some of the above characteristics, the pond in the Japanese Memorial Gardens has a thriving population of roughskin newts. It is well worth a trip down there in the summertime to observe the newts interacting with one another and coming up to the surface for a quick gulp of air!
Roughskin newts are predators to slugs, worms, aquatic invertebrates, aquatic larvae such as mosquitos, and amphibian larvae and eggs, and it’s important to do what we can to support their role in the ecosystem. If you have a pond on your property and you want to make it more wildlife friendly, give us a call to schedule a free landholder consultation with biologist Rob Underhill. You can also check out this video here.
Want to know some other cool facts about roughskin newts? They have a concentration of Tetrodotoxin on their skin, which is a powerful neurotoxin causing paralysis and death if eaten (other creatures with Tetrodotoxin include pufferfish and the blue ringed octopus). Although the concentration of poison varies regionally and can be quite mild, there have been records of newts with enough poison to kill 20 adult humans. In those instances, the roughskin newt surpasses the world’s most poisonous amphibian, the golden poison dart frog (10 adult humans)! This high concentration of Tetrodotoxin is likely caused by the ‘evolutionary arms race’ roughskin newts and garter snakes are engaged in. Although hooded mergansers on Mayne Island have been observed squeezing and rinsing newts prior to consumption, garter snakes are the only known predator to have developed a specific resistance to Tetrodotoxin, and as roughskin newts increase their poisonous capacity to counter this, garter snakes increase their antitoxin in response. It is a slow and thrilling affair.
So, if you spot a newt on the road and you feel inclined to help them to the other side (if you can tell which way they’re headed), make sure to wash your hands afterwards. Better yet, wear gloves or a leaf when handling amphibians. The oils from our hands can reduce their ability to breath through their skin. Watch out for them when you’re riding your bike, and if possible, driving your car. Let’s help these amphibians get where they need to go!