WESTERN RED-BACKED SALAMANDER by Rosemary Jorna
Several years ago we found a Western Red-Backed Salamander (Plethodon vehiculum) in our yard, but I had not seen one anywhere since. Last fall that changed. The Greater Victoria Green Team (GVGT)and Habitat Acquisition Trust (HAT) were working on invasive plant removal in Ayum Creek Park. HAT was also conducting a quick survey of the biodiversity, checking the bases of ferns and the edges of rotting logs for salamanders. There at the base of a rotting stump was Plethodon vehiculum, a small, slender salamander about 10 cm long with tail and body both having the same width. A wide rusty stripe ran the full length of its dark body keeping it well camou aged as it was much the same colour as the rotting wood. We left it untouched as salamanders, like most amphibians, have very sensitive skins.
The discovery started me reviewing salamanders. There are three species of terrestrial salamanders on Vancouver Island. They are a woodland species, preferring moist areas with maturing trees and lots of woody debris. They have no lungs. Oxygen is absorbed through their skin over their whole body and through the lining of their mouths. They need moisture and a clean environment to survive, so it is no surprise that they are most often seen in the wet weather. They are carnivores and spend most of their time hidden under logs and leaf mould, venturing out after dark to hunt for spiders, mites, isopods and small insects.
Terrestrial salamanders do not breed in water. In the spring they lay eggs underground, in moist rotting wood or duff. The mother stays with the eggs for months, trying to keep them clean and safe until they hatch in the fall. Miniature copies of adults emerge: all their metamorphasis has taken place within the egg.
A few weeks after the Ayum Creek encounter, the Otter Point and Shirley Residents and Ratepayers Association (OPSRRA) was cleaning up on Otter Point Road. I was called over to a garbage covered slope where volunteers had uncovered a cluster of more than 18 pearl-like eggs. The eggs were too big for slugs. Our best guess was one of the terrestrial salamanders.
Back to the books. The Wandering Salamander (Aneides vagrans), is uncommon. They hang their eggs in strings not clusters. Ensatina escholtzii produces 8 to 10 eggs in a clutch. By elimination, Western Red-Backed salamander, (Plethodon vehicular) with a clutch size of 8 to 20 eggs was the most likely mother. She should have been close by as these salamanders occupy a very small territory of a few square meters. They are neighbourly home bodies, not prone to wandering or defending their territories. They are willing to live in close proximity if the food supply is good.
Unfortunately there was no sign of the mother, and there was no indication that the embryos had developed. It may be that the dump site was toxic to salamanders or that something ate the mother. The 2015/16 attempt to reproduce failed, but if she survived it will be late in the summer of this year (2017) before she recovers enough energy to breed again. If she has recovered she will release pheromones. A nearby male will pick up the scent. If his head butting and neck rubbing suits her, she will walk up behind him straddling his tail they stroll along. It is this behaviour that gives these salamanders the second part of their Latin name, vehiculum. He is acting as a vehicle for her. During the walk he will drop a single spermatophore, a package of sperm. He can do this every year. She will pick it up and store it inside her body, in a spermatheca, over the winter and into the spring of 2018 when she will use it to fertilize her developing eggs. If she is successful in raising that clutch they will emerge in the fall of 2018 as tiny, perfect 2.5 to 3 cm salamanders ready to grow into adults and breed in 2020 or 2021. There is a record of this salamander living for 11 years in captivity but life in the wild is generally shorter so realistically a female has 3 to 4 chances to raise a brood.
My third encounter was during a very wet hike on Broom Hill. Brian spotted this salamander. It was doubled up on a at stone with the water running around it. He protected it from careless feet as we crossed a small stream on the narrow trail. We might have moved it if I had read further, since Western Red-Backed salamanders can drown if they cannot get out of the water. The best photo of Plethodon Vehiculum was taken in the Sooke Hills that week by Jean Oke.