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Rhyacotriton olympicusOlympic Torrent Salamander

By Stephanie DiPonzio

Geographic Range

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)

Habitat

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)

  • Aquatic Biomes
  • rivers and streams
  • Range elevation
    0 to 1200 m
    0.00 to 3937.01 ft
  • Average depth
    less than one m
    ft

Physical Description

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)

  • Sexual Dimorphism
  • female larger
  • Range length
    94 to 97 mm
    3.70 to 3.82 in

Development

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)

Reproduction

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)

  • Breeding interval
    This species generally breeds once yearly.
  • Breeding season
    Breeding season peaks in May, but exact breeding time varies considerably on an individual basis.
  • Range number of offspring
    2 to 16
  • Average number of offspring
    8
  • Range time to hatching
    210 to 295 days
  • Range age at sexual or reproductive maturity (female)
    4 to 5 years
  • Range age at sexual or reproductive maturity (male)
    4 to 5 years

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)

  • Parental Investment
  • no parental involvement

Lifespan/Longevity

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)

Behavior

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)

Home Range

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)

Communication and Perception

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)

Food Habits

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)

  • Animal Foods
  • insects

Predation

Although there are no confirmed predators of this species, garter snakes and giant salamanders are considered potential predators. (Akios, 2008; Hayes and Jones, 2012)

  • Known Predators
    • Giant salamander (Dicamptodontidae sp.)
    • Garter snake (Thamnophis sp.)

Ecosystem Roles

Caudouterina rhyacotriton, an intestinal trematode, has been found in Olympic salamanders. (Martin, 1966)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

There are no known benefits to humans presented by this species.

Economic Importance for Humans: Negative

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)

Conservation Status

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)

Other Comments

Olympic salamanders are Urodeles and, as such, can regenerate lost limbs.

Contributors

Stephanie DiPonzio (author), Hobart & William Smith Colleges, Jim Ryan (editor), Hobart & William Smith Colleges, Jeremy Wright (editor), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

aposematic

having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

freshwater

mainly lives in water that is not salty.

insectivore

An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

sperm-storing

mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

tactile

uses touch to communicate

taiga

Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

visual

uses sight to communicate

References

"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.

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