California Reptiles & Amphibians

Taricha rivularis - Red-bellied Newt

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Range in California: Red

Dot-locality Range Map

Aquatic adult, Mendocino County

Terrestrial phase adult,
Mendocino County

Breeding adult male, Mendocino County

Adult underwater, Mendocino County

Aquatic adult, Mendocino County

Underside of breeding adult male showing dark color on elbows and across swollen vent, Mendocino County

Underside of breeding adult male, Mendocino County

Terrestrial phase adult, Sonoma County
(note the dark eye, with no yellow)

Breeding, Eggs, and Larvae

Breeding adult male in aquatic phase, Mendocino County

Mass of breeding adults, Mendocino County © Jessica Miller -
Livingunderworld.org

Aquatic male newts patrolling the shallow waters of a Mendocino County breeding creek before the females arrive.

Adults amplexing in shallow water

Adults amplexing underwater

in situ adults as found hiding under a log, Sonoma County. © Kate Britsch

During the breeding season, adult males develop nuptial pads on the toes to improve their ability to hold onto females during amplexus.

Adult newt and single egg,
Mendocino County
© Jessica Miller - Livingunderworld.org

Eggs, Mendocino County
© Jessica Miller - Livingunderworld.org

Eggs, Sonoma County. © 2008 Arnaud Jamin.
From the CalPhotos collection.

Larva in late August, Mendocino County

Larvae underwater in creek, late August, Mendocino County

Larvae underwater in aquarium, late August, Mendocino County

Habitat

Habitat, creek during early breeding season, March, Mendocino County

Habitat, Sonoma County

Habitat, creek during breeding season, late February, Mendocino County

Habitat, creek during early breeding season, March, Mendocino County

Habitat, creek during breeding season, early March, Mendocino County

Habitat, redwood forest, Mendocino County

Breeding creek in late August, Mendocino County

Short Videos

Red-bellied newts at their breeding creek in the redwood forest in Mendocino County.

Male Red-bellied newts walking around a creek at the beginning of the breeding season, waiting for females to arrive.

Two male Red-bellied newts try to steal a female away from a male in amplexus with her, but they do not succeed.

Breeding male newts move around underwater in a small aquarium.

Description

Size

Adults are 2 3/4 - 3 1/2 inches long (7 - 8.9 cm) from snout to vent, and 5 1/2 - 7 1/2 inches (14 - 19.5 cm) in total length.

Appearance

A stocky, medium-sized, salamander with grainy skin, no costal grooves, and dark eyes. (Other Taricha species have yellow in the eye.) Breathes through lungs. Brownish black above, tomato red below. There is dark coloring on the undersides of the limbs and a dark band across the vent which is especially broad in males and often absent in females. Breeding males develop smooth skin, a flattened tail to aid with swimming, a swollen vent, and rough nuptial pads on the undersides of the feet to aid in holding onto females during amplexus.

Larvae have numerous, fine black spots along the sides and back. The dorsal fin and balancers are not well-developed, compared to other Taricha species, but the hindlimb development is more advanced at hatching. Larvae retreat into vegetation and under stones during the day.

Behavior and Natural History

Adults are terrestrial, becoming aquatic when breeding. Adults emerge after a few fall rains and move around feeding for a period before migrating to the breeding stream. (Adults that are not breeding that year, continue to forage on the forest floor.) Acitivity typically occurs at night and in the late afternoon, but newts are also found active in streams and on the surface in daylight during the breeding season and during rains. Often seen moving in large numbers to breeding sites during breeding season. Terrestrial animals spend the dry summer in moist habitats under woody debris, rocks, in animal burrows.

When threatened, this newt assumes a swaybacked defensive pose, closing its eyes, extending its limbs to the sides. Unlike the other Taricha species, Red-bellied newts do not elevate or curl the tail. They sometimes lift the entire front of the body up off the ground, keeping the tail, pelvis, and hind limbs on the ground. This "unken reflex" exposes its bright red ventral surface coloring which is a warning to potential predators.

Poisonous skin secretions containing tetrodotoxin repel most predators. This potent neurotoxin is widespread throughout the skin, muscles, and blood, and can cause death in many animals, including humans, if eaten in sufficient quantity. (One study estimated that 25,000 mice could be killed from the skin of one Rough-skinned newt, the most toxic of the Taricha species.) This poison can also be ingested through a mucous membrane or a cut in the skin, so care should always be taken when handling newts.
In most locations the Common Gartersnake, Thamnophis sirtalis, is has a high resistance to this poison, and is known to prey on Red-bellied Newts.

Juveniles apparently spend most of their time underground and are not active on the surface until near sexual maturity. Coexists with T. granulosa but unlike that species, T. rivularis breeds in flowing, not still, water. Sometimes hybridizes with T. granulosa.

At one time, Red-bellied Newts were very abundant at some locations. One estimate from the early 1960's was that there were 58,000 - 60,000 breeding newts in a 1.5 mile (2.5 km) long stretch of Pepperwood Creek.

Longevity is estimated to be 20 - 30 years.

Diet

Eats a variety of invertebrates. Larvae most likely eat anything they can fit in their mouth.

Reproduction and Young

Reproduction is aquatic. Breeding migration begins as early as late January, with adult males entering the water as early as early February. Very heavy rainfall inhibits migration, as the newts need to wait until the streams recede from winter floods. Breeding takes place from late February to May, peaking in March, in clean rocky streams and rocky rivers with moderate to fast flow. Adults will leave the water during heavy rains when the flow is high. Ponds, lakes, and other standing waters are avoided.

Newts typically return to the same part of the same creek throughout their life. Experiments have shown that they have an excellent homing ability to find their native stream segment using their sense of smell. There is no evidence that they are territorial and defend their stream segment from others.

Males breed more frequently than females - usually every year or every 2 years, while females breed every 2 or more years. Males arrive at the streams 1-3 weeks before females. In the water, they transform into their aquatic phase, with loose skin, swolen cloacal lips, and an enlarged and flattened tail that aids them in swimming. They patrol the edges of the stream waiting for females to arrive. When they arrive, the females are sometimes mobbed by a group of males until one has grabbed onto her back in amplexus and cannot be wrestled off by the other males. Males develop nuptial pads on the fingers and toes to help their grip.

The male hangs on to the female in amplexus until she is ready to fertilize her eggs. At that time, the male deposits a spermatophore and the female picks it up with her cloaca. The female lays and attaches a flattened egg mass usually only one egg layer thick under stones in the middle of the creek or rocks overhanging the creek, or onto submerged roots. Clutch size is about 10 eggs. Many egg masses are sometimes found under one stone. Temperature determines how long the egss take to hatch. In a laboratory, eggs hatched faster at a higher temperature (16 - 20 days) than at a lower temperature (30 - 34 days.)

The larval stage lasts about 4 - 6 months. In one population, the larvae hatched in late April, and transformed in late August. Metamorphosis typically occurs in late summer and early fall. Transformed juveniles leave the stream and go into hiding in underground shelters where they spend most of their life until they are old enough to breed (4 - 6 years.)

Range

Endemic to California. Occurs along the coast from near Bodega, Sonoma county, to near Honeydew, Humboldt county, and inland to Lower lake and Kelsey Creek, Lake County. The most limited in distribution of the three species of Taricha.

Habitat

A stream or river dweller. Found in coastal woodlands and redwood forest along the coast of northern California.

Conservation Issues (Conservation Status)

Development of forests and grassland habitats for agriculture and housing may pose a serious threat by drying out the land and degrading streams, and creating more vehicular traffic with corresponding road mortality of terrestrial newts, especially during breeding migrations.

Taxonomy
Family	Salamandridae	Newts
Genus	Taricha	Pacific Newts
Species	rivularis	Red-bellied Newt
Original Description
Twitty, 1935 - Copeia, p. 73 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Taricha: Greek - preserved mummy, possibly referring to the rough skinned appearance. rivularis: Latin - of a brook or stream. from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
None
Related California Salamanders
Taricha torosa torosa - Coast Range Newt Taricha torosa sierrae - Sierra Newt Taricha granulosa - Rough-skinned Newt
More Information and References
Natureserve Explorer California Dept. of Fish and Game AmphibiaWeb Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Behler, John L., & F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992. Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Amphibians of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009. Bishop, Sherman C. Handbook of Salamanders. Cornell University Press, 1943. Lannoo, Michael (Editor). Amphibian Declines: The Conservation Status of United States Species. University of California Press, June 2005. Petranka, James W. Salamanders of the United States and Canada. Smithsonian Institution, 1998. Jones, Lawrence L. C. , William P. Leonard, Deanna H. Olson, editors. Amphibians of the Pacific Northwest. Seattle Audubon Society, 2005.

Conservation Status
The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game. This salamander is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.
Organization	Status Listing
U.S. Endangered Species Act (ESA)	None
California Endangered Species Act (CESA)	None
California Department of Fish and Game	None
Bureau of Land Management	None
USDA Forest Service	None
Natureserve Global Conservation Status Ranks
World Conservation Union - IUCN Red List

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