The winter rains bring about a transformation in California’s Coast Ranges. After the dry summer and fall, the soil becomes moist, plants spring back to life and ponds fill. The rains also signal the beginning of the march of the amphibians. After months of dwelling near moist seeps or living underground, frogs and newts come to the surface. The air fills with the sound of pacific chorus frogs (Pseudacris regilla). Here is a photo of a male calling his heart out, as well as a video of the little dude.
While the songs of the frogs make a clear auditory impact, the California Newts (Taricha torosa) make a more visual impact. Tan on the back, and orange on the belly, the newts carry a potent toxin in the skin. This provides a powerful protection against predators; as a result the newts walk overland with apparently no fear. On rainy days and nights, hundreds of thousands of these brown and orange amphibians can be found moving in the same direction, like a primitive herd of ancient beasts. Their movement is not random; they are heading to the ponds and streams where they will breed. Males typically arrive first, sliding into the ponds to wait for females.
The newts have complex mating behavior, involving tactile and chemical cues and specific behaviors. This video below shows breeding behavior of California Newts (Taricha torosa) observed in Napa County, California in February 2010. In the first part of a video, a male newt can be seen clinging to the back of a female newt; this behavior is called ‘amplexus’. While in amplexus, the male strokes the female with his hindlimbs to encourage her to accept him as a mate. Two other male newts then approach the amplexed newts; one of them swims past the mating pair. The second part of the video shows a male newt slowly swimming through the water. The third part of the video shows a female newt clinging to vegetation and attempting to lay eggs. Several other newt egg masses (round jelly balls filled with white eggs) can be seen on the same piece of vegetation. A male newt clings to the back of the female newt, even though she is in the process of already laying eggs. Another male newt approaches the pair, and then swims past. Throughout the whole video, Pacific Chorus Frogs (Pseudacris regilla) sing a beautiful nighttime chorus.
Newt mating can also get crazier than single males paired with females. In some cases, three, four, five or more males will cling to a single female. In some cases, this activity can get extreme enough to drown some of the individuals in the mating ball. Eventually the female will select a mate. Fertilization is internal, males leave a packet of sperm underwater. The female picks it up with her cloaca. Once the eggs are fertilized, she lays them in small balls of 5 to 75 eggs.
After over a decade of fieldwork and observing thousands of newts, I occasionally find individuals with deformities. In 2010, while visiting several ponds with a colleague, we observed a male California Newts with an usual set of deformities. His right hind foot was split, and he had an unusual pair of protuberances coming out of his tail. The hind foot deformity was no real shocker; while this is the first time I’ve seen a limb deformity out of thousands of Taricha torosa I’ve looked at, limb deformities have been described in many amphibians. I’ve also seen occasional limb deformities in frogs and salamanders. What really caught our attention were the strange protuberances on the salamander’s tail. I had never seen deformities like this before, and they are not commonly reported in many of the scientific publications on the topic. It left us wondering what caused them … parasite infection? . . . tumor? If you’ve got an idea, let me know.