Rhyacotriton olympicus
Olympic salamanders are dark brown dorsally with white guanophore spots. They are usually yellow ventrally, with dark patches in some individuals. These salamanders typically range between 94 and 97 mm in length, with females being larger than males. (Akios, 2008; Wake, et al., 1987)
Olympic salamanders are found mainly in coastal areas of the Olympic Peninsula of Washington to northwestern Oregon. Some populations have also been found from southwestern Oregon to Mendicino County, California, and within the Cascade Mountains of Washington and Northern Oregon. (Wake, et al., 1987)
Olympic salamanders live in humid climates within the forests of the coastal western United States, preferring cooler climates than most other salamanders. They are native to well-forested (largely coniferous) mountain ranges. Generally, they are found in and near streams or running water; they are rarely further than one meter from such an environment and are rarely found deeper than several millimeters under water. These salamanders are often found within moist cliff faces or under rock debris in stream beds. (Good and Wake, 1992; Nussbaum and Tait, 1977)
As with most other salamanders, this species undergoes an aquatic juvenile phase, with external gills and a paddle-shaped tail. Olympic salamanders are approximately 13 mm upon hatching and typically grow to between 30.2 and 38.6 mm following metamophosis. Metamorphosis may occur at any time of year but is most common in late summer of the third year. (Nussbaum and Tait, 1977)
This species breeds year round, peaking in the Spring. Males are typically more aggressive during breeding periods and use a distinctive tail movement, where only the tail tip is moved, to attract the attention of females before depositing a spermatophore; females then grasp the spermatophore with theur cloacal lips and fertilization takes place internally. Courtship is presumed to take place on land or within the splash zone of streams. (Arnold, 1977; Nussbaum and Tait, 1977; Verrell, 1989; Zug, et al., 2001)
This species utilizes internal fertilization through cloacal spermatophores produced by the male and taken in by the female. Females may store spermatazoa in spermathecae and may mate with multiple males before laying egg clutches (though it is uncertain how common this is); this species likely mates more than once during a breeding season. They will not participate in courtship until they have reached sexual maturity. Eggs are typically deposited in creek or stream beds where they hatch. The embryonic period, including the time before hatching and after, when the embryo is still feeding on the egg yolk, is estimated at 360 days. Larvae can be as small as 13.5 mm and individuals begin to metamorphose into juveniles between 4-5 years of age (38-26 mm). During metamorphosis, larvae lose their gill slits and external gills. (Hayes and Jones, 2012; Nussbaum and Tait, 1977; Zug, et al., 2001)
Due to the inaccessibility of nests to predators, there is little need for parental care in this species; additionally, due to the long period between egg laying and the larval stage, it would be nearly impossible for a female to remain with her nest and care for young. This trait varies from the typical situation in salamanders, as oophagy is common among many other species. The eggs produced by Olympic salamanders are large (in comparison to those produced by other salamanders), few in number, and are unpigmented. The characteristicly large eggs are consistent with a lack of parental care; however, the relatively small number of eggs produced is further evidence that they are deposited in a location safe from predation. (Nussbaum, 1985; Ryan, 1977; Sever, 2003)
There is currently no information available regarding the lifespan of Olympic salamanders; however, based on data from other Rhyacotriton species, they are assumed to have a moderately long lifespan of greater than 10 years. (Hayes and Jones, 2012)
Male Olympic salamanders may display aggressive behavior toward each other, particularly during breeding periods. The contrasting yellow belly and farker dorsum is thought to be aposematic, with threatened individuals coiling the body, elevating the tail, and lashing it at the threat to show off this coloration. (Hayes and Jones, 2012; Verrell, 1989)
Specific information regarding the home range of this species is unavailable, but in other Rhyacotriton species has been found to be limited to a scale of a few meters. (Hayes and Jones, 2012)
Although there is no definite data on the matter, it is possible that males of this species utilize their cloacal vent glands in releasing pheromones to communicate with other individuals. Olympic salamanders also sense their environments through visual and tactile cues. (Sever, 1988)
These salamanders feed primarily upon insects such as springtails (Collembola), piptera, and stonefly (Plecoptera) nymphs. The have also been found to prey upon other aquatic life found in streams, such as amphipods. (Bury, 1970)
Although there are no confirmed predators of this species, garter snakes and giant salamanders are considered potential predators. (Akios, 2008; Hayes and Jones, 2012)
Caudouterina rhyacotriton, an intestinal trematode, has been found in Olympic salamanders. (Martin, 1966)
Deforestation is detrimental to the conservation of Olympic salamanders, posing potential problems to the logging industry functioning throughout its habitat. (Corn and Bury, 1989; Welsh, 1990)
There are no known benefits to humans presented by this species.
The logging industry, common in the northwestern United States, is detrimental to the conservation of this species, as deforestation impacts the sedimentation of streams that these salamanders live in and around. Deforestation is also problematic, as the salamanders are found primarily in older forests due to the lack of necessary microhabitat conditions in deforested areas. (Corn and Bury, 1989; Welsh, 1990)
Olympic salamanders are Urodeles and, as such, can regenerate lost limbs.
Stephanie DiPonzio (author), Hobart & William Smith Colleges, Jim Ryan (editor), Hobart & William Smith Colleges, Jeremy Wright (editor), University of Michigan-Ann Arbor.
"Regeneration in Urodeles" (On-line). Urodele Amphibians: The Regenerative Vertebrate Exception. Accessed October 26, 2012 at http://www.bio.davidson.edu/courses/anphys/2000/Grayson/GRAYSON.HTM.
Akios, C. 2008. Habitat Loss and the Utility of an Old-growth Corridor for Herpetofauna in Olympic National Forest. Ann Arbor, MI: ProQuest Information and Learning Company.
Arnold, S. 1977. The evolution of Courtship Behavior in New World Salamanders with Some Comments on Old World Salamanders. The Reproductive Biology of Amphibians: 141-183.
Bury, B. 1970. Food Similarities in the Tailed Frog, Ascaphus truei, and the Olympic Salamander, Rhyacotriton olympicus. Copeia, Vol. 1970, No. 1: 170-171.
Corn, P., B. Bury. 1989. Logging in Western Oregon: Responses of Headwater Habitats and Stream Amphibians. Forest Ecology and Management, Vol 29, Issues 1-2: 39-57.
Good, D., D. Wake. 1992. Geographic variation and speciation in the Torrent salamanders of the genus Rhyacotriton (Caudata: Rhyacotritonidae). Berkeley: University of California Press.
Hayes, M., L. Jones. 2012. "Rhyacotrion olympicus" (On-line). AmphibiaWeb. Accessed October 22, 2012 at http://amphibiaweb.org/cgi/amphib_query?where-genus=Rhyacotriton&where-species=olympicus.
Martin, G. 1966. Caudouterina rhyacotritoni gen. et sp. n. (Trematoda: Digenea) from the Olympic Salamander. The Journal of Parasitology, 52/5: 935-938.
Nussbaum, R., C. Tait. 1977. Aspects of the Life History and Ecology of the Olympic Salamander, Rhyacotriton olympicus (Gaige). American Midland Naturalist, Vol. 98, No. 1: 176-199.
Nussbaum, R. 1985. The evolution of parental care in salamanders. Ann Arbor: Museum of Zoology, University of Michigan.
Ryan, M. 1977. Parental Care in Salamanders. Bulletin of the New York Herpetological Society, Vol. 13, No. 2: 23-28.
Sever, D. 2003. Reproductive biology and phylogeny of Urodela. Enfield, NH: Science Publishers.
Sever, D. 1988. Male Rhyacotriton olympicus (Dicamptodontidae: Urodela) Has a Unique Cloacal Vent Gland. Herpetologica, 44/3: 274-280.
Verrell, P. 1989. The Sexual Strategies of Natural Populations of Newts and Salamanders. Herpetologica, 45/3: 265-285.
Wake, D., G. Wurst, D. Good. 1987. Patterns of geographic variation in allozymes of the Olympic Salamander, Rhyacotriton olympicus (Caudata: Dicamptodontidae). Fieldiana. Zoology., 32: 1-15.
Welsh, H. 1990. Relictual Amphibians and Old-Growth Forests. Conservation Biology, 4/3: 309-319.
Zug, G., L. Vitt, J. Caldwell. 2001. Herpetology: An Introductory Biology of Amphibians and Reptiles. San Diego, CA: Academic Press.