California newt
One small feature of the Sonoma Mountain winter is the emergence of newts, specifically the rough-skinned newt (Taricha granulosa) and the California newt (Taricha torosa). Newts are a subgroup of salamanders. However, unlike most salamanders that spend most of their lives on land beneath logs, leaf litter, or the occasional patio or garbage bin (where they congregate at my house), newts are more strongly adapted to life in water, particularly during the breeding season. Their webbed feet and paddle-like tails make them powerful swimmers. Outside of breeding season, they inhabit woodland and chaparral habitats, usually close to the ponds and creeks where they reproduce. Rough-skinned newts range from Alaska to California, while California newts are endemic to our state.
Sonoma Mountain’s newts are toxic, secreting a potent neurotoxin from their skin called tetrodotoxin (the same one found in puffer fish). It is hundreds of times more toxic than cyanide; thus, California’s toxic newts have few natural predators. Garter snakes, however, developed a genetic resistance to tetrodotoxin. The mutations in the snake’s genes that build resistance to the toxin resulted in newts that produced more potent levels of toxin. This increase in newt toxicity produces a genetic pressure favoring snakes with mutations that have even greater resistance. This “evolutionary arms race” has resulted in newts that produce levels of toxin far higher than what is needed to kill any other predator. Beware the mighty newt!
Sonoma Mountain’s newts begin reproduction with the winter rains, typically starting in December and continuing through early May. They most often return to the same pools or stream reaches where they grew up. Courtship involves an intricate dance ritual in which the male hops onto the female’s back and rubs his chin over her nose and flutters his tail. The female California newt lays gelatinous egg masses containing between seven and 30 eggs, attaching them to submerged plant roots or rocky crevices. Rough-skinned newts may lay well over 30 eggs, often singly or in small clusters. Larvae of both species hatch from late spring into early summer, but are challenging to find, their mottled bodies blending seamlessly with the sandy streambed.
Image courtesy Sally Gale and the Chileno Valley Newt Brigade.
There are several ways to tell the two newts apart, though none are entirely reliable. California newts tend to be a bit larger, usually growing six to eight inches long, while rough-skinned newts are slightly smaller at five to seven inches. California newts also have more prominent, “buggy” eyes, with light brown or orange coloring beneath them that matches their bright orange bellies. Rough-skinned newts have dark lower eyelids and a yellow to more muted orange belly, with additional differences in skin texture and defensive posture visible in the labeled image accompanying this article. Both species primarily feed on small invertebrates, such as insects, worms, and even snails. To complicate matters further, the two species are known to cross-breed, creating hybrids that don’t fit neatly into either category, a reminder that nature rarely follows tidy definitions.
Sonoma Mountain is home to remarkable diversity, much of it easily overlooked. Paying attention to creatures like newts—small, ancient, and persistent—reminds us that the mountain is alive with stories unfolding at our feet. The more closely we pay attention, the more clearly we develop our sense of place within our shared world.
