Harbingers of spring, amphibians in Kitsap County include both frogs and salamanders. The iconic body form and vocalizations of frogs are familiar, but less well known are their quiet brethren, the salamanders. Like most amphibians, salamanders have a two-stage life history involving an aquatic, free-living larval stage followed by metamorphosis into a small terrestrial adult.

The Plethodontids, ‘lungless salamanders’, are the contrarians in this scheme, depositing their fertilized eggs terrestrially in damp, rotting wood and the like. Their larval stage occurs entirely within the egg. What ultimately emerges is a tiny version of an adult. 

Our local aquatic-breeding amphibians reproduce mostly in late winter or early spring, commonly in small, fishless ponds and streams. Upon reaching a suitable breeding pond, male frogs advertise their location and availability for reproduction with deafening vocal choruses, thus attracting females. From our perspective salamanders appear naturally silent. Their drive to reproduce is expressed in their migratory capabilities — sexually mature adults of both sexes know where their pond is and how to get to it. We just don’t hear about it.

Red-legged frogs, male and female in a mating embrace. photo by Tom Doty

In salamanders the newly hatched form is simply referred to as a salamander larva. There’s no confusing a larval salamander with a frog tadpole. The former looks like a tiny adult salamander with all four legs and a tail. The only visible larval characteristics are the feathery external gills emerging from each side of the head. Salamander larvae, like the adults they will become, are predatory carnivores, eating any animal in the pond small enough to swallow. Food consists mostly of larval and adult macroinvertebrates (aquatic bugs big enough to see), although in some cases early breeding in salamanders leads to larvae big enough to eat tadpoles of frogs breeding later in the season.

Ultimately the larval salamanders will have to leave their pond. Water levels, food and oxygen are all in decline. For amphibia in general this means it’s time for metamorphosis — the structural and functional changes required by the transition to terrestrial life. In salamanders these changes are simpler than in frogs, requiring only the resorption of the external gills, to be replaced in most, by lungs. These juvenile salamanders then disperse into the surrounding terrestrial environment, paying attention as they leave because ultimately they will need to find their way back.

Northwestern Salamander. photo by John F. Williams

In frogs, the first to reach a suitable pond are able to advertise that fact vocally, attracting other males and, importantly, females to the party. Salamanders, having no broadcast-level voice, must depend on the navigational skills of their potential mates to find the pond and one another. Except for the brief appearance of spermatophores (the sperm packets deposited by exuberant males on the pond bottom) and the ultimate presence of egg masses we might never have known they were there.

The reproductive success of amphibians is not simply a matter of academic interest to humans. Passerine (perching) birds (about 70% of all birds) are having difficulty calcifying their eggs, one factor contributing to declining bird populations. Calcium is a common nutrient in aquatic systems but is less available terrestrially — increasingly acidic rainfall dissolves and washes it away. In times past, temporary ponds and intermittent streams produced uncountable numbers of tiny emergent frogs and salamanders carrying their calcium-rich bones into the surrounding forest where they became the opportunistic source of calcium for predatory birds and other terrestrial vertebrates. However, the decline in amphibian populations worldwide has resulted in further reductions in calcium availability terrestrially.

Rough-skinned newt. photo by John F. Williams

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