Peaks of Otter salamanders (Plethodon hubrichti) are named after the area in which they are most heavily populated, Peaks of Otter, in the Appalachian Mountains of Virginia. These three peaks are among about a 19-km stretch in the Blue Ridge Mountains in the Virginia counties of Botetourt, Rockbridge, and Bedford. (Hammerson and Mitchell, 2004; Thurow, 1957)
Peaks of Otter salamanders are terrestrial creatures that live at elevations of 446-1067 m within their restricted range. They inhabit the floor of Appalachian hardwood forests and are often found underneath logs or rocks in moist, vegetated sections of the forest. Farallo and Miles (2016) analyzed the habitats of various members of Family Plethodontidae, and found Peaks of Otter salamanders to more likely occupy areas of slightly warmer temperatures. Overall, in comparison to similar eastern red-backed salamanders (Plethodon cinereus) and Big Levels salamanders (Plethodon sherando), Peaks of Otter salamanders are more of a generalist species when it comes to habitat selection. (Arif, et al., 2007; Farallo and Miles, 2016; Mitchell, et al., 1996)
Peaks of Otter salamander body lengths for adults range from 8.1 cm to 13.1 cm. The minimum snout-vent length (SVL) at sexual maturity is 39 mm for both sexes. They have a black color base, darkest on the dorsum and becoming slightly more grey around the ventral region. They become lighter at the tips of the fingers and head, appearing almost translucent with a purple tint. Stretching from the top of the head over halfway down the dorsal region into the tail, they have small clumps of gold flakes. These patches of gold flakes sometimes nearly cover the entire dorsal area. Peaks of Otter salamanders can also be albino, as one has been observed in Botetourt County.
These salamanders have a body this is a round tube-shape, slightly pressed on the anterior of the dorsum. Their skull is almost completely flat and triangular, with the eyes bulging on either corner of the flat skull. Although females have a slightly more rounded nose and a slightly larger torso compared to males, the sexes are are fairly similar. Adult males possess a mental gland on their chin, used during the breeding season.
Peaks of Otter salamanders bear a close resemblance to Cheat Mountain salamanders (Plethodon nettingi). Peaks of Otter salamanders are darker and possess more gold on the dorsal region. (Kniowski and Reichenbach, 2009; Mitchell, et al., 1996; Thurow, 1957)
Peaks of Otter salamander eggs have seldom been studied. Eggs that have been found were in a clutch size of ten eggs, each about 5 mm in diameter. Like other members of Family Plethodontidae, Peaks of Otter salamanders lay their eggs in a terrestrial environment: underneath logs, leaves, or other damp places in the soil. Plethodontid salamanders normally undergo metamorphosis before they hatch, with no aquatic larval stage. Both sexes reach sexual maturity at an SVL of 39mm.
Like other members of the genus Plethodon, these salamanders exhibit indeterminate growth. Growth continues until they reach around 10cm. At this point, growth slows. (Kniowski and Reichenbach, 2009; Marvin, 2001; Mitchell and Wicknick, 2005; Reichenbach and Sattler, 2007)
Peaks of Otter salamanders are monogamous during a reproductive cycle. Mating is assumed to take place underneath logs, grass, and brush in the moist areas in which they live. With Family Plethodontidae salamanders, although never formally observed in Peaks of Otter salamanders, males will "slap" (touch) the female's snout with their mental gland, expressing desire to mate via pheromones. This is followed by male excretion of a spermatophore, later to be inseminated by the female. (Jaeger, et al., 1995; Mitchell and Wicknick, 2005)
Little is known about the reproduction means of Peaks of Otter salamanders. They breed once yearly in September-October. Eggs are laid by the females about eight to nine months later at the beginning of summer, and the eggs hatch in August and into September. The young are independent upon hatching. The number of offspring ranges from 5 to 15, and time to hatching is 2 to 3 months. Average birth mass has not been published. The size at which both males and females reach sexual maturity is a snout-vent length of at least 39 mm. This size usually occurs at about 3.5 years. (Jaeger, et al., 1995; Kramer, et al., 1993; Mitchell and Wicknick, 2005; Reichenbach and Sattler, 2007)
Little is known about Peaks of Otter salamander parental investment, but females have been observed in attendance of nests. Males provide no parental investment beyond the act of mating. (Mitchell and Wicknick, 2005)
Exact lifespan figures for Peaks of Otter salamanders are not known. However, a closely related species, the red-cheeked salamander (Plethodon jordani), has an average lifespan in the wild of around ten years. It is suspected that Peaks of Otter salamanders have a similar lifespan in the wild. They are not kept in captivity. (Hairston, 1983)
Peaks of Otter salamanders, like similar salamander species, have very small home ranges. The extremely closely-related species Cheat Mountain salamander (Plethodon nettingi) will generally find a wet, damp spot underneath leaves or logs, and remain within a few meters of that spot. Peaks of Otter salamanders are thought to be aggressively territorial, protecting their territory even from members of their own species.
They are mostly nocturnal, because of the lower temperature and humidity. Peaks of Otter salamanders use pheromones via mental glands during reproduction, as well as other other communication tactics. They are not careful (compared to other members of Family Plethodontidae) when it comes to feeding, as their diet includes insects and arthropods, as well as small flowers and herbs. (Homyack and Haas, 2009; Jaeger, et al., 1995; Petranka and Murray, 2001)
Home range area for Peaks of Otter salamanders is about 0.6 m^2. Kramer et al. (1993) measured the median distance moved, which was 1 m. Here, we report the home range as the defended territory, due to their aggressive nature. (Dodd, Jr. and Brodie, Jr., 1976; Highton, 1999; Kramer, et al., 1993; Mitchell and Wicknick, 2005)
Not a lot is known about the communication habits of Peaks of Otter salamanders specifically, but many salamanders are known to communicate with each other via chemical signals, or pheromones. Peaks of Otter salamanders have also been known to bite eastern red-backed salamanders (Plethodon cinereus) in lab studies. Although not seen in the field, these two salamanders do occur sympatrically in the wild. Peaks of Otter salamanders possess a mental gland used for chemoreception, similar to other member of Family Plethodontidae. (Arif, et al., 2007; Dodd, Jr. and Brodie, Jr., 1976; Gibbons and Buhlmann, 2001)
Peaks of Otter salamanders are omnivores, as they consume small flowers and other herbaceous plants along the forest floor, as well as many arthropods and insects. In addition to small herbaceous plants, prey include worms, ants, isopods, collembolans, beetles, spiders, gastropods, lepidopteran larvae, and centipedes. Studies have shown that Peaks of Otter salamanders are opportunistic eaters. (Kramer, et al., 1993; Mitchell and Wicknick, 2005; Thurow, 1957)
Exact predators of Peaks of Otter salamanders are not known, but potential predators that occur sympatrically include northern ring-necked snakes (Diadophis punctatus), milk snakes (Lampropeltis triangulum), black racers (Coluber constrictor), and eastern garter snakes (Thamnopis sirtalis). Additional predators could include northern short-tailed shrews (Blarina brevicauda), southeastern shrews (Sorex longirostris), wild turkeys (Meleagris gallopavo), and brown thrashers (Toxostoma rufum).
Peaks of Otter salamanders avoid predation through a number of techniques. First, they avoid detection by becoming immobile. Their cryptic coloration presumably helps them avoid detection. Studies of intentional disturbance recorded these salamanders as remaining motionless for 1.5 seconds, up to 99 seconds. These animals also release a noxious chemical, secreted through the skin, which hinders potential predators. Finally, they also have some sort of defense posture, though it is not well-described. (Gibbons and Buhlmann, 2001; Jaeger, et al., 1995; Kramer, et al., 1993; Mitchell and Wicknick, 2005)
Peaks of Otter salamanders, similar to other Plethodon species, do not have much interaction with other species in their ecosystem. They carve out a role in the ecosystem by eating their prey, including small insects, as well as acting as a predator to animals such as snakes and shrews. No parasites have been reported for these salamanders. (Kniowski and Reichenbach, 2009; Mitchell and Wicknick, 2005; Messere and Ducey, 1998; Reichenbach and Brophy, 2017)
There are no known positive economic effects of Plethodon hubrichti on humans.
There are no known negative economic effects of Plethodon hubrichti on humans.
The IUCN Red List status of Plethodon hubrichti is "Vulnerable," last assessed in April 2004. Peaks of Otter salamanders do not appear in the CITES appendix nor the United States Endangered Species Act list. They have no status on the State of Michigan list. The IUCN vulnerable designation is due to the species being located in fewer than five areas, although Peaks of Otter salamanders are sometimes abundant in these few areas. In addition, Peaks of Otter salamanders are a "Species of Concern" by the Virginia Department of Game and Inland Fisheries, "Federal Species At Risk" by the United States Fish and Wildlife Service, and a "Sensitive Species" by the United States National Forest Service.
Clear-cutting in the Appalachian Mountains is a possible future threat to Peaks of Otter salamanders, as clearcut sites show well fewer salamanders than at mature, wooded sites. Other potential threats include other logging activities, and even loss of canopy due to gypsy moths (Lymantria dispar).
The geographic range for Peaks of Otter salamanders, located mainly in the Jefferson National Forest, is an area that is monitored and protected. Close monitoring of the population is needed due to the limited geographic range. Currently, conservation plans are in effect in the entire geographic range of Peaks of Otter salamanders that are very restrictive on logging practices. (Hammerson and Mitchell, 2004; Mitchell and Wicknick, 2005; Mitchell, et al., 1996; Reichenbach and Sattler, 2007)
Maxwell Barney (author), Radford University, Layne DiBuono (editor), Radford University, Lindsey Lee (editor), Radford University, Kioshi Lettsome (editor), Radford University, Karen Powers (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
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.
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.
an animal that mainly eats meat
uses smells or other chemicals to communicate
active at dawn and dusk
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
union of egg and spermatozoan
an animal that mainly eats leaves.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly plants or parts of plants.
Animals with indeterminate growth continue to grow throughout their lives.
An animal that eats mainly insects or spiders.
fertilization takes place within the female's body
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).
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.
Having one mate at a time.
having the capacity to move from one place to another.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
chemicals released into air or water that are detected by and responded to by other animals of the same species
breeding is confined to a particular season
remains in the same area
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).
Living on the ground.
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
uses sight to communicate
Arif, S., D. Adams, J. Wicknick. 2007. Bioclimatic modelling, morphology, and behaviour reveal alternative mechanisms regulating the distributions of two parapatric salamander species. Evolutionary Ecology Research, 9: 843-854.
Dodd, Jr., C., E. Brodie, Jr.. 1976. Observations on the mental hedonic gland-cluster of eastern salamanders of the genus Plethodon. Chesapeake Science, 17/2: 129-131.
Farallo, V., D. Miles. 2016. The importance of microhabitat: A comparison of two microendemic species of Plethodon to the widespread P. cinereus. Copeia, 104/1: 67-77.
Gibbons, J., K. Buhlmann. 2001. Reptiles and amphibians. Pp. 372-390 in J Dickson, ed. Wildlife of Southern Forests: Habitat and Management. Surrey, British Columbia: Hancock House Publishers.
Hairston, N. 1983. Growth, survival and reproduction of Plethodon jordani: Trade-offs between selective pressures. Copeia, 1983/4: 1024-1035.
Hammerson, G., J. Mitchell. 2004. "Plethodon hubrichti" (On-line). The IUCN Red List of Threatened Species e.T17632A7217814. Accessed September 02, 2018 at http://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T17632A7217814.en.
Highton, R. 1999. Geographic protein variation and speciation in the salamanders of the Plethodon cinereus group with the description of two new species. Herpetologica, 55/1: 43-90.
Homyack, J., C. Haas. 2009. Long-term effects of experimental forest harvesting on abundance and reproductive demography of terrestrial salamanders. Biological Conservation, 142/1: 110-121.
Jaeger, R., E. Prosen, D. Adams. 2002. Character displacement and aggression in two species of terrestrial salamanders. Copeia, 2002/2: 391-401.
Jaeger, R., J. Wicknick, M. Griffis, C. Anthony. 1995. Socioecology of a terrestrial salamander: Juveniles enter adult territories during stressful foraging periods. Ecology, 76/2: 533-543.
Kniowski, A., N. Reichenbach. 2009. The ecology of the Peaks of Otter salamander (Plethodon hubrichti) in sympathy with the eastern red-backed salamander (Plethodon cinereus). Herpetological Conservation and Biology, 4/3: 285-294.
Kramer, P., N. Reichenbach, M. Hayslett, P. Sattler. 1993. Population dynamics and conservation of the Peaks of Otter salamander, Plethodon hubrichti. Journal of Herpetology, 27/4: 431-435.
Lewis, J., G. Connette, M. Deyrup, J. Carrel, R. Semlitsch. 2014. Relationship between diet and microhabitat use of red-legged salamanders (Plethodon shermani) in southwestern North Carolina. Copeia, 2014/2: 201-205.
Marvin, G. 2001. Age, growth, and long-term site fidelity in the terrestrial Plethodontid salamander Plethodon kentucki. Copeia, 2001/1: 108-117.
Messere, M., P. Ducey. 1998. Forest floor distribution of northern redback salamanders, Plethodon cinereus, in relation to canopy gaps: First year following selective logging. Forest Ecology and Management, 107/1-3: 319-324.
Mitchell, J., J. Wicknick. 2005. Plethodon hubrichti. Pp. On-line reproduction in M Lannoo, ed. Amphibian Declines: The Conservation Status of the United States Species. Berkeley, California: University of California Press.
Mitchell, J., J. Wicknick, C. Anthony. 1996. Effects of timber harvesting practices on Peaks of Otter salamander (Plethodon hubrichti) populations. Amphibian & Reptile Conservation, 1/1: 15-19.
Petranka, J., S. Murray. 2001. Effectiveness of removal sampling for determining salamander density and biomass: A case study in an Appalachian streamside community. Journal of Herpetology, 35/1: 36-44.
Reichenbach, N., T. Brophy. 2017. Natural history of the Peaks of Otter salamander (Plethodon hubrichti) along an elevational gradient. Herpetological Bulletin, 141: 7-15.
Reichenbach, N., P. Sattler. 2007. Effects of timbering on Plethodon hubrichti over twelve years. Journal of Herpetology, 41/4: 622-629.
Semlitsch, R., K. O'Donnell, F. Thompson III. 2014. Abundance, biomass production, nutrient content, and the possible role of terrestrial salamanders in Missouri Ozark forest ecosystems. Canadian Journal of Zoology, 92/12: 997-1004.
Thurow, G. 1957. A new Plethodon from Virginia. Herpetologica, 13/1: 59-66.