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taricha torosa, taricha granulosa, taricha rivularis, california newt, rough skinned newt, red bellied newt
Taricha (Gray, 1850) Western Newts, Pacific Newts

Taricha torosa (Rathke, 1883) California Newt
Taricha granulosa (Skilton, 1849) Rough Skinned Newt
Taricha rivularis (Twitty, 1935) Red Bellied Newt 


Newts of the genus Taricha are collectively referred to as Western Newts, a reflection of their distribution throughout the western coast of the U.S. and Canada. There are three species in the genus Taricha, all of which are similar in appearance and behavior. In the wild, all three species overlap in habitat at some point, and hybridization is common between T. granulosa and T. torosa, and occasional between T. granulosa and T. rivularis, and T. rivularis and T. torosa. T. torosa and T. granulosa are difficult to tell apart at first glance, but can be distinguished by a few unique characteristics (detailed below). T. rivularis are easily distinguished from the other two species by their tomato red bellies and protruding eyes.

Table 1.1: Comparison of differentiating physical characteristics of T. torosa, T. granulosa, and T. rivularis, outside of the breeding season.

Taricha torosa possess light colored lower eye lids and subocular area compared to Taricha granulosa.

Taricha granulosa possess dark colored lower eye lids and subocular area compared to Taricha torosa.

Taricha rivularis possess large, protruding eyes, and red colored snouts and subocular area.

Taricha torosa possess yellow-orange, solid colored bellies. 

Taricha granulosa possess yellow-orange bellies. A sharper contrast between dorsal and ventral coloration may also be noticed when compared to T. torosa.

Taricha rivularis possess tomato red bellies, a characteristic never observed in T. granulosa or T. torosa.
Photos © Gary Nafis, California Reptiles and Amphibians, http://www.californiaherps.com
For more photos, see the Caudate Gallery.
 

Taricha granulosa inhabit the most varied environments, owing to its large distribution. Some populations may hibernate during the winter, breeding in the temperate summer, while others may aestivate during the warm summer, emerging to breed during the rainy winter. T. torosa and T. rivularis have rather small distributions, mostly in Northern California, although T. torosa are also found in the Sierra Nevada to southern California.


Taricha torosa (Rathke, 1833) California Newt

Taxonomic Synonyms: Salamandra beecheyi (Gray, 1831), Triton torosa (Rathke, 1883), Triton ermani (Weigmann In Erman, 1835), Salamandra beecheyi (Gray, 1839), Pleurodles californiae (Gray, 1850), Taricha torosa (Gray, 1850), Notophthalmus torosus (Baird, 1850), Taricha laevis (Baird & Girard, 1853), Triton laevis (Strauch, 1870), Diemyctylus torosus (Cope, 1875), Triton torosus (Wiedersheim, 1877), Molge torosa (Boulenger, 1882), Cynops torosus (Cope, 1883), Amblystoma rubrum (Reid, 1895), Diemictylus torosus (Fowler & Dunn, 1917), Triturus torosus (Dunn, 1918), Taricha torosa klauberi (Wolterstorff, 1935), Taricha torosa torosa (Wolterstorff, 1935), Taricha torosa forma monstrosa (Scharlinski, 1939), Triturus sierrae (Twitty, 1942), Triturus torosus klauberi (Twitty, 1942), Taricha klauberi (Smith & Taylor, 1948), Triturus torosus sierrae (Stebbins, 1951), Taricha sierrae (Wahlert, 1952), Taricha torosa torosa (Schmidt, 1953), Taricha sierrae (Collins, 1991)
Vernacular Names: California Newt, Pacific Coast Newt, Coast Range Newt, Sierra Newt (spp. sierrae)

Taricha torosa are typically chocolate brown to tannish-brown dorsally, with yellow to burnt orange bellies, and highly granular skin. During the breeding season, males develop smooth and lighter colored skin, enlarged mental glands, laterally compressed tail fins, and tiny cornified papillae (nuptial pads) on the toes and hind limbs. The limbs of T. torosa are thick and powerful, hence the species name "torosa", which references the muscular limbs and head. T. torosa are rather large newts, reaching up to 8 inches long, with some exceptional individuals surpassing the average length.  

T. torosa is often confused with sympatric Taricha granulosa (Rough-Skinned Newt), a nearly identical relative. T. torosa can be distinguished from T. granulosa by their Y-shaped vomerine teeth, lighter lower eyelid, defensive posturing (in sympatric populations), and the position of the eyes relative to the margin of the head. The following table summarizes the physical differences between the two species.

 

Table 1.2 - Physical comparison of Taricha granulosa and Taricha torosa torosa.
Characteristic Taricha torosa torosa Taricha granulosa
Lower eyelid and sub-ocular color  Light colored: yellow-orange  Dark colored: brown
Vomerine teeth pattern  Y shaped V shaped
Defensive posture Tail is held straight out, with the tip held straight or dropped downward; tail is never curled toward the head. Tail held straight out, often with the tip curled inward toward the head.
Eye position Eyes protrude past the margin of the head when viewed from above.  Eyes do not exceed the margin of the head when viewed from above, or are significantly less protuberant. 

 

Table 1.3 - Head profiles and defensive postures of T. granulosa and T. torosa.

Taricha granulosa granulosa. Eyes do not protrude past the margin of the head when viewed from above. Photo © Gary Nafis, California Reptiles and Amphibians 

Taricha torosa torosa. Eyes protrude past the margin of the head when viewed from above. Photo © 2005 Jessica Miller, jess@livingunderworld.org  

Taricha granulosa granulosa. Common defensive posture with the tail tip curled inward toward the head Photo © Gary Nafis, California Reptiles and Amphibians 
Taricha torosa sierrae. Photo © Gary Nafis, California Reptiles and Amphibians
Taricha torosa sierrae. Defensive posture; the tail tip is never curled toward the head. Photo © Gary Nafis, California Reptiles and Amphibians   

 

Although differences summarized in Table 1.1 are used to distinguish T. torosa from T. granulosa, the vomerine teeth pattern are a definitive characteristic that distinguishes both T. torosa subspecies from T. granuosa, whereas the others are sometimes observed in both species. T. torosa and T. granulosa may also be mistaken for T. rivularis, although physical characteristics are more distinguishable in T. rivularis. T. rivularis differ from T. torosa and T. granulosa in having markedly protruding eyes, tomato red bellies (always absent in T. torosa and T. granulosa), and brown irises.  

An isolated population in San Diego Co., that possesses extraordinarily warty skin is sometimes treated as a third subspecies, T. t. klauberi. However, only two subspecies, T. t. torosa and T. t. sierrae are generally accepted today.

T. t. torosa are found along coastal ranges from northwestern to southwestern California. Northern populations of T. t. torosa inhabit mesic forests or mountainous terrain. Southern populations are found in drier habitats, including oak forests, rolling grasslands, and chaparral. T. t. sierrae inhabit pine forests that are drier than those of T. t. torosa. T. t. torosa typically breed in slow-moving or still ponds and ditches, whereas T. t. sierrae often breed in faster flowing streams, as they are better adapted for such an environment.

 

Taricha torosa torosa. Photo © 2002 William Flaxington, Field Observations of Calif. Amphibians and ReptilesTaricha torosa torosa (Rathke, 1883) California Newt, Coast Range Newt
T. t. torosa occur in coastal ranges from northwestern to southwestern California. T. t. torosa are chocolate brown dorsally, with yellowish to orangish bellies. T. t. torosa can be distinguished from T. t. sierrae by the lack of conspicuous light coloring on the eyelid and snout that is apparent on T. t. sierrae, however the only definitive method is knowing the exact locality of the specimen in question. 

The photo at left shows a young T. t. torosa, note the absence of light coloration around the snout, and reduced light coloration around the upper eye lid when compared to T. torosa sierrae.


Taricha torosa sierrae. Photo © Gary Nafis, California Reptiles and AmphibiansTaricha torosa sierrae (Twitty, 1942) California Newt, Sierra Newt
T. t. sierrae are found in the Sierra Nevada area of California. T. t. sierrae are chocolate brown to reddish brown dorsally, with burnt orange bellies. The eyelid and snout have noticeable light coloring, and breeding males develop smaller tail fins than those of T. t. torosa

The photo at left shows a young T. t. sierrae, note the lighter colored upper eye lid, lighter coloration around the snout, and rusty-burnt orange coloration about the tail, abdomen, and feet.


Taricha torosa sierrae. Adult from Fresno Co., Calif. Photo © Gary Nafis, California Reptiles and Amphibians 

Taricha torosa torosa. Adult from Napa Co., Calif. Photo © 2005 Jessica Miller, jess@livingunderworld.org  

Taricha torosa torosa. Abnormally colored male in breeding dress from Los Angeles, Calif. Photo © David Frischling fonzerella@earthlink.net, Jeff Fonda, and Sean Ramirez.

Taricha torosa torosa. Adult from Napa Co., Calif. Photo © 2005 Jessica Miller, jess@livingunderworld.org  

Taricha torosa torosa eggs. Adult from Napa Co., Calif. Photo © 2005 Jessica Miller, jess@livingunderworld.org  

Taricha torosa sierrae habitat, Kern Co., Calif. Photo © Gary Nafis, California Reptiles and Amphibians  
For more photos, see the Taricha torosa gallery

Breeding
Mating occurs in shallow waters, usually after a period of summer aestivation. In northern California populations, breeding occurs anywhere from December to May, depending on the elevation, local conditions, and rain pattern, and typically last for 6-12 weeks. T. t. sierrae typically breed between January and February. In general, migration to breeding sites is prompted by the first heavy rains of the season. In some areas, hundreds of migrating newts can be observed each year as they make their trek to the ponds. Locals have even noted newts accidentally entering houses or garages that may obscure their path to the ponds. Males arrive at the breeding sites before females, and usually remain in the water longer. Juveniles also migrate, but do not breed. Adult males and females typically breed every other year.

Courtship is similar to that of T. rivularis and T. granulosa, and consists of the male amplexing the female in the water by embracing her just behind her shoulder region, and hooking his chin over her snout. While in amplexus, the male will produce secretions from the mental gland, located on the chin, which are intermittently rubbed along the females snout. The secretions from the mental gland apparently stimulate reception from the female. Pheromones are produced from the cloaca, are are intermittently fanned about with the tail. Courtship usually lasts for 40-60 minutes, sometimes longer, at which point the male will deposit a spermatophore and signal the female to collect it by making lateral hip movements. The female will collect the spermatophore with her cloacal lips and proceed to egg deposition after a gestation period. After deposition of a spermatophore, the male may amplex the female a second time. Males may mate several times during each season, sometimes with the same partner, while females typically reject advances made by other males after mating with a particular male. As with T. torosa, males may try to dislodge the male from an amplexed pair, creating a "newt knot".

Females deposit gelatinous egg masses to submerged twigs, aquatic vegetation, rocks, aquatic leaf litter, or other debris, whereas the eggs of T. rivularis and T. granulosa are deposited singly. Egg masses may contain 5-25 eggs, but on average consist of 10-15 eggs. After a few hours of deposition, the egg masses swell to a diameter of a few inches. Often times, several egg masses are attached to one object. Females are also known to deposit egg masses directly on the floor of the water area, unattached to surrounding debris, or in small masses on fallen leaves. In a typical breeding site, egg masses can be observed every foot or two in shallow waters, near the shore. T. t. sierrae typically produce larger eggs, approximately .7mm larger than T. t. torosa

T. torosa do feed while in the water, and will not hesitate to consume their eggs and larvae.

Larvae are pond type, with long gills and tall tail fins. Larval coloration is creamy yellow, with two dark colored, dorso-lateral stripes running from the back of the head to the tail. The stripes of T. t. torosa are regular, while those of T. t. sierrae are irregular. Metamorphosis generally occurs in late Summer to early Autumn.  

Juvenile T. torosa will remain terrestrial for the first 5-8 years of life. Although most will migrate during the breeding season, sexual maturity is not reached for at least a few years.

 


Taricha torosa torosa. Photo © 2005 Jessica Miller, jess@livingunderworld.org 

Taricha torosa sierrae adults in amplexus. Photo © Gary Nafis, California Reptiles and Amphibians 

Taricha torosa torosa female depositing eggs. Photo © Gary Nafis, California Reptiles and Amphibians   

Taricha torosa torosa egg masses. Photo © 2004 Jessica J. Miller, jess@livingunderworld.org  

Taricha torosa torosa newly hatched larva. Photo © 2004 Jessica J. Miller, jess@livingunderworld.org  

Taricha torosa sierrae older larvae. Photo © William Flaxington, Field Observations of California Amphibians and Reptiles.
For more photos, see the Taricha torosa gallery.



Taricha granulosa (Skilton, 1849) Rough Skinned Newt

Taxonomic Synonyms: Salamandra (Triton) granulosa (Skilton, 1849), Triturus granulosus (Twitty, 1935), Triturus similans (Twitty, 1935), Triturus granulous granulosus (Bishop, 1941), Triturus granulosus twittyi (Bishop, 1941), Triturus granulosus similans (Myers, 1942), Triturus granulosus mazamae (Myers, 1942), Triturus granulosus mazamae (Bishop, 1943), Taricha granulosa (Wahleert, 1952), Taricha granulosa granulosa (Schmidt, 1953), Taricha granulosa mazamae (Schmidt, 1953), Taricha granulosa similans (Schmidt, 1953), Taricha torosa granulosa (Pimentel, 1958), Taricha torosa mazamae (Pimentel, 1958), Taricha torosa twittyi (Pimentel, 1958), Taricha torosa simulans (Pimentel, 1958)
Vernacular Names: Rough-skinned Newt, Rough-skin Newt, Roughskin Newt, Rough Skinned Newt, Oregon Newt (Bishop, 1943), Crater Lake Newt (spp. mazamae)

Taricha granulosa are very similar in appearance to T. torosa, with chocolate brown to tannish-brown dorsal coloration, yellow to orange bellies, and granular skin, although the contrast from dorsal to ventral coloration is usually sharper in T. granulosa. T. granulosa may also possess a dark, almost black, dorsal coloration. T. granulosa can be distinguished from T. torosa by their V-shaped vomerine teeth, darker lower eyelid, defensive posturing (in sympatric populations), and the position of the eyes. The following table summarizes the differences between the two species.

 

Table 1.2 - Physical comparison of Taricha torosa torosa and Taricha granulosa.
Characteristic Taricha torosa torosa Taricha granulosa
Lower eyelid and subocular color Light colored: yellow-orange  Dark colored: brown
Vomerine teeth pattern  Y shaped V shaped
Defensive posture  Tail is held straight out, with the tip held straight or dropped downward; tail is never curled toward the head. Tail held straight out, often with the tip curled inward toward the head.
Eye position Eyes protrude past the margin of the head when viewed from above.  Eyes do not exceed the margin of the head when viewed from above, or are significantly less protuberant. 


Table 1.3 - Head profiles and defensive postures of T. granulosa and T. torosa.

Taricha granulosa granulosa. Eyes do not protrude past the margin of the head when viewed from above. Photo © Gary Nafis, California Reptiles and Amphibians 

Taricha torosa torosa. Eyes protrude past the margin of the head when viewed from above. Photo © 2005 Jessica Miller, jess@livingunderworld.org  

Taricha granulosa granulosa. Common defensive posture with the tail tip curled inward toward the head Photo © Gary Nafis, California Reptiles and Amphibians 
Taricha torosa sierrae. Photo © Gary Nafis, California Reptiles and Amphibians
Taricha torosa sierrae. Defensive posture; the tail tip is never curled toward the head. Photo © Gary Nafis, California Reptiles and Amphibians 


Although differences summarized in Table 1.1 are used to distinguish T. granulosa from T. torosa, the vomerine teeth pattern are a definitive characteristic that differentiate T. granulosa from both subspecies of T. torosa, whereas the others are sometimes observed in both species. T. granulosa and T. torosa may also be mistaken for T. rivularis, although physical characteristics are more distinguishable in T. rivularis. T. rivularis differ from T. torosa and T. granulosa in having markedly protruding eyes, tomato red bellies (always absent in T. torosa and T. granulosa), and brown irises. Breeding T. rivularis males do not produced a noticeable tail fin, and unlike T. granulosa and T. torosa, breeding T. rivularis females develop the same velvety smooth skin as the males.

During the breeding season, males develop smooth and lighter colored skin, enlarged cloaca, laterally compressed tail fins, and cornified papillae (nuptial pads) on the toes and hind limbs. In breeding mode, females often develop lighter, smoother skin, and laterally compressed tails, as well, although to a lesser degree than males. During the terrestrial season, T. granulosa possess noticeably granulous skin, hence the name Rough Skinned Newt. T. granulosa can reach 7.5 - 8 inches, sometimes larger, and males generally larger than females.

T. granulosa are generally biphasic, but adults retaining gills, gill slits, and gill remnants have been documented in Crater Lake, Oregon, Latah Co., Idaho, and San Mateo Co., California. In southern Oregon, neotenic populations have been documented at high elevations, in several lakes. There are also differentiations between populations in the southern and northern populations of T. granulosa's distribution. In general, individuals in the southern most range are increasingly larger than those from the northern ranges. Some Alaskan, Oregon, and northern California populations are often dorsally and ventrally mottled with dark coloration. At one point, four subspecies, granulosa, mazamae, similans, and twittyi, were recognized based on the differences in physical appearances. Today, a set of two subspecies, granulosa and mazamae, are accepted for the most part.

Taricha granulosa are found along the western border of North America, from Alaska to California, and from sea level to 9,000 feet. Their habitat is generally mesophytic forests, and the occasional grassland during the terrestrial season. Terrestrials are often found in riparian, douglas-fir, redwood, and hardwood-conifer woods. Like many newt species, T. granulosa prefer to remain hidden under logs, rocks, leaf litter, or other cryptic hiding places. Aquatic habitats include ponds, lakes, slow moving streams, or sluggish sections of streams. Individuals in British Columbia have been found in water as deep as 40 feet. Some individuals have occasionally been observed traipsing through brackish waters, as well. In the water, T. granulosa sometimes seek shelter in the substrate of soft-bottomed areas. Taricha granulosa are the most aquatic species of the genus, and are occasionally found in water outside of the breeding season. Adults in some populations remain aquatic year round, or enter the water several times per year.

Presumably introduced, isolated populations have been found near Moscow (Latah Co.), Idaho, and Saunders Co., Montana.

Taricha granulosa granulosa (Skilton, 1849) Rough Skinned Newt
T. g. granulosa are found from southern Alaska to Northern California, along the western coastline. The distribution ends in Santa Cruz County, California, and overlaps with T. torosa torosa in northern California habitats, for which it hybridizes with. T. g. granulosa are found in woodland forests, and sometimes open grasslands in terrestrial phases. During the aquatic season, T. g. granulosa will occupy vernal pools, permanent lakes, slow streams, and sometimes the faster moving areas of streams.  
Taricha granulosa mazamae (Myers, 1942) Crater Lake Newt
T. g. mazamae are found exclusively in Crater Lake, Oregon. This subspecies may be wholly dark brown, or possess blotched dark coloration on the dorsum and/or venter.



Taricha granulosa granulosa. Photo © 2001 Jessica J. Miller, jess@livingunderworld.org 

Taricha granulosa granulosa. Adult female from Santa Cruz Co., Calif. Photo © Gary Nafis, California Reptiles and Amphibians  

Taricha granulosa granulosa. Adult from Mendocino Co., Calif. Photo © Gary Nafis, California Reptiles and Amphibians  

Taricha granulosa granulosa. Adult female from Santa Cruz Co., Calif. Photo © Gary Nafis, California Reptiles and Amphibians  

Taricha granulosa granulosa. Adult female from Santa Cruz Co., Calif. Photo © Gary Nafis, California Reptiles and Amphibians  

Taricha granulosa granulosa habitat, San Mateo Co., Calif. Photo © Gary Nafis, California Reptiles and Amphibians
For more photos, see the Taricha granulosa gallery


Breeding
Taricha granulosa granulosa breeding male. Photo courtesy of Henk Wallays, Henk.Wallays@pandora.be During the breeding season, males develop compressed tail fins, smooth and lighter colored skin, nuptial pads on the hind limbs, and enlarged cloaca. Females may also develop lighter colored and smoother skin, to a lesser degree. The photo at right shows a typical male in breeding mode, with the fore mentioned characteristics.

In general, terrestrial-phase adults emerge from their summer hiding places and begin migration to the breeding ponds (usually the same ponds they hatched and developed from) in masses. Like T. torosa, in some areas, large migrating groups may accidentally invade home that cross their migratory path.

The breeding season varies for different populations, and newts have been documented at breeding sites in every month of the year. In many populations, breeding is prompted when the temperature begins to drop, and rainfall increases, however, many higher elevation populations, and T. g. mazamae in Oregon, are known to breed during the summer months. The following table shows a brief summary of the breeding season and behavior of some T. granulosa populations.

 

Table 1.3: Brief summary of breeding seasons of various, nonspecific populations of T. granulosa (material adapted from Petranka, 1998)
Population Migration and breeding season
Misc. low to moderate elevations  March to May
Misc. high elevations June to August (Summer)
Oregon - Crater Lake (T. g. mazamae) June to August (Summer)
Oregon - misc. low elevations beginning in November, peaking from January to March.
Oregon - misc. low to moderate elevations beginning in February
Oregon - misc. high elevations as late as August
California - misc. streams remain semi-aquatic year round, except during severe climate.
California (N.) - misc. high elevations as late as October
British Columbia - Lake Marion April to late September
British Columbia - southern Vancouver Islands females migrate from March to September or November, and males remain semi-aquatic year round.


Courtship is similar to that of T. rivularis and T. torosa, and consists of the male amplexing the female in the water by embracing her just behind her shoulder region, and hooking his chin over her snout. While in amplexus, the male will produce secretions from the mental gland, located on the chin, which are intermittently rubbed along the females snout. The secretions from the mental gland apparently stimulate reception from the female. Pheromones are produced from the cloaca, are are intermittently fanned about with the tail. Courtship usually lasts for 40-60 minutes, sometimes longer, at which point the male will deposit a spermatophore and signal the female to collect it by making lateral hip movements. The female will collect the spermatophore with her cloacal lips and proceed to egg deposition after a gestation period. After deposition of a spermatophore, the male may amplex the female a second time. Males may mate several times during each season, sometimes with the same partner, while females typically reject advances made by other males after mating with a particular male. As with T. torosa, males may try to dislodge the male from an amplexed pair, creating a "newt knot".

When in the water, T. granulosa do not eat. Some adults may leave the water for periods of time, at which point food consumption may commence. In some populations, the newts may take breaks from breeding, leaving the water for several days, sometimes as long as a month.

Females typically attach their eggs singly or in strings to submerged vegetation and rocks, as opposed to the large, gelatinous clumps produced by T. torosa females. Females of some populations are known to fold their eggs singly in submerged leaves, and some have been noted as depositing eggs directly on the floor of the water area, unattached to surrounding debris. In the wild, larvae can be found grouped in warm microhabitats, until the temperature exceeds about 85°F, at which point they disperse into cooler areas. Metamorphosis is typically reached within 4-4.5 months, however, some at higher elevations may over-winter and transform the following Summer. T. g. mazamae typically hatch around August, and transform at the beginning of the following Summer, whereas many California populations may transform in late Summer or early Autumn. 

Juveniles are terrestrial for the first 4-8 years of life. In some California populations, juveniles are seen as often on the ground surface as adults. 


Taricha rivularis (Twitty, 1935) Red Bellied Newt

Taxonomic Synonyms: Triturus rivularis (Twitty, 1935), Taricha rivularis (Wahlert, 1952)
Vernacular Names: Red-bellied Newt, Redbelly Newt, Red Bellied Newt

Taricha rivularis are usually dark brown or black dorsally, with characteristic solid, tomato red bellies and toes, which make T. rivularis easily distinguishable from the other two species. T. rivularis also possess more protuberant eyes, brown irises, and a distinct, dark band across the cloaca of males. During the breeding season, males become velvety in appearance, with lighter colored and smoother skin, swollen cloaca, and mildly compressed tails. The skin of breeding females also becomes lighter and smoother, with a velvety appearance. 

T. rivularis has the smallest range of all three species, which includes the northern California counties of Mendocino, Sonoma, and Humboldt. The terrestrial habitat is mainly redwood forests, which are moderately abundant in these counties. T. rivularis may breed in moderate-fast flowing streams and creeks, and rarely in vernal pools. 


Taricha rivularis Photo © Gary Nafis, California Reptiles and Amphibians 

Taricha rivularis Photo © Gary Nafis, California Reptiles and Amphibians

Taricha rivularis habitat, Mendocino Co., Calif. Photo © 2004 Jessica J. Miller, jess@livingunderworld.org
For more photos, see the Taricha rivularis gallery

 

Breeding
Although active during the fall, T. rivularis congregate at breeding sites just before the waters begin receding from winter rains, usually in late January to late March. Breeding takes place in shallow streams and creeks, typically in mild to moderately fast flowing water. Like the other species, T. rivularis return to the same breeding sites every year. Males arrive at the sites a few weeks before the females, and are already in the water when the females arrive. T. rivularis will temporarily leave the water during heavy rains, returning when the rainfall lets up. During the breeding season, breeding sites are packed with newts in the water and on the shoreline. Studies have shown that males seem to breed every year consistently, whereas females may skip a year or two.

Males and females develop smooth, lighter colored skin that takes on a velvety appearance during the breeding season. The tail becomes mildly compressed, but less compressed than T. torosa and T. granulosa

Courtship is similar to that of T. torosa, and consists of the male amplexing the female in the water by embracing her just behind her shoulder region, and hooking his chin over her snout. While in amplexus, the male will produce secretions from the mental gland, located on the chin, which are intermittently rubbed along the females snout. The secretions from the mental gland apparently stimulate reception from the female. Pheromones are produced from the cloaca, are are intermittently fanned about with the tail. The male may or may not clasp his hind legs around the females hindquarters, and at some point begins stroking the females abdomen and hind legs with his hind legs. After approximately 15-60 minutes, sometimes longer, the female will raise her snout, at which point the male will rub it vigorously with his chin. This seems to be some sort of indication from the female, for shortly after, the male will release her, deposit a spermatophore, and motion to the female to collect it by tapping the substrate with his feet and rocking back and forth. 

When in the water, T. rivularis do not hunt food items, however, egg consumption has been observed in captivity.

Both males and females tend to mate several times, sometimes with the same partners. The spermatophores and eggs of T. rivularis are more adhesive than other Tarichids, owing to the fact that they typically breed in moving streams.

Eggs are deposited singly, but in clusters consisting usually of 2-3 eggs, on the undersides of rocks and plant stocks, and sometimes on the substrate. The eggs appear flattened, and are brownish yellow in color. Breeding streams are typically shaded by surrounding redwood trees, which allow the sun to penetrate and warm up patches of the water. The water temperature is usually around 50°F-68°F in the wild, and warmer in sun exposed areas, and the eggs hatch around 25 days later. Warmer water causes the eggs to hatch quicker, and colder water causes a longer incubation period. Larvae have been noted to prefer warmer temperatures, between 68°F-75°F. In the wild, larvae can be found grouped in warm microhabitats, until the temperature exceeds about 85°F, at which point they disperse into cooler areas. 

Metamorphosis occurs approximately 4 months after hatching; usually around August in the wild. Like the other species, T. rivularis juveniles are terrestrial and secretive for the first 5 or more years of their lives.


Taricha rivularis ball of breeding newts. Photo © 2004 Jessica J. Miller, jess@livingunderworld.org   

Taricha rivularis in wild habitat. Photo © 2004 Jessica J. Miller, jess@livingunderworld.org   

Taricha rivularis amplexing adults. Photo © 2004 Jessica J. Miller, jess@livingunderworld.org   

Taricha rivularis amplexing adults. Photo © 2004 Jessica J. Miller, jess@livingunderworld.org   

Taricha rivularis two day old eggs. Photo © 2004 Jessica J. Miller, jess@livingunderworld.org   

Taricha rivularis adult and egg. Photo © 2004 Jessica J. Miller, jess@livingunderworld.org   
For more photos, see the Taricha rivularis gallery



Annual Breeding Migration
In general, Tarichids are terrestrial for a time during the year, and migrate to breeding sites during their season. Tarichids are unique among other salamanders in that they return to the same ponds and streams to breed that they emerged from, every year. Some individuals may trek up to .3 miles from their terrestrial refuge to their breeding site. Studies have shown that newts displaced several hundred meters can find their way back to their home ranges. There are a few theories as to the origin of the great homing senses of Tarichids. 

Tarichids are thought to recognize odors and, to a lesser degree, topographic cues, and will trek long distances if necessary to reach their breeding sites. Robert Stebbins, UCB Herpetologist, documented migrating specimens exuding fluids from their cloaca as they travel, presumably leaving behind olfactory trail marks (Sheppard). The recognition of celestial cues has also been suggested, as well as kinesthesia. Kinesthetia is a recognition of ones physical orientation, in relation to the surroundings. The recognition of topographic and celestial cues is somewhat doubtful, at least as major homing cues, because Tarichds often times migrate during heavy rains, and cloudy nights, which would obscure the visibility of the sky and surroundings. Also, blinded, displaced T. rivularis have been shown to find their way back home, with little or no more difficulty than those that were not blinded. 

Etymology & Nomenclature
Taricha (Greek) = Preserved mummy; in reference of the rough, warty skin of Taricha species.
   torosa (Latin): Muscular, fleshy; in reference of the thick head, body, and limbs.
             sierrae: Refers to the distribution in the Sierra Nevada.
   granulosa (Latin): Many small grains, also in reference to the granular skin.
             mazamae: Refers to the distribution near Mt. Mazama, Oregon.
   rivularis (Latin): Stream-dweller, breeds only in streams.

Toxicity (Tarichatoxin and TTX)
Newts are toxic creatures, as are all members of the family Salamandridae. Their toxins are found in the granular skin glands, and are secreted when the salamander feels threatened.  The degree of toxicity varies among newt species, with Tarichids at the top of the ladder; adult s and juveniles possess enough poison to cause serious health problems to mammals as large as adult humans, if ingested.

Newt poison was dubbed tarichatoxin, after its isolation in a newt of the genus Taricha. Tarichatoxin has been shown specifically to cause hypertension, respiratory paralysis, and nerve unresponsiveness in small mammals (Fuhrman, 1986). Quastel (1941) showed that tarichatoxin inhibits oxygen consumption in brain cells produced by electrical stimulation, which he linked to an influx in sodium ions, eluding to a disruption of the voltage-gated sodium channels (Auyoung, 1999).

Tarichatoxin* is an aminoperhydroquinazoline poison that is biochemically identical to the water-soluble alkaloid tetrodotoxin (anhydrotetrodotoxin 4-epitetrodotoxin, tetrodonic acid), or TTX, the third most potent non-protein neurotoxin known to exist; surpassed only by palytoxin and maitotoxin, which are approximately 100 times more poisonous than TTX. However, tarichatoxin has approximately 1% the potency of TTX. TTX is similar to saxitoxin, which is present in dinoflagellates (red tide) and responsible for shellfish poisoning, but differs in its method of inhibiting the sodium channel.

Upon entering the blood stream, TTX blocks the sodium channels of excitable membranes, causing paralysis in the nerves and muscles, during which the victim is usually fully conscience (Fuhrman, 1986; Yasumoto et al., 1986). Because of this unique characteristic, voodoo practitioners and others have long used TTX-containing animals as “magical substances” to turn people into zombies; toxic animal parts are crushed into a powder and slipped into the victim’s meal or drink. One such account describes a Haitian man that was slipped this magic powder, and subsequently pronounced dead at the onset of paralysis and his inability to speak. When the TTX wore off several days later, the man tried to return home to his family, but was turned away because he was thought to be a walking-dead zombie (Light, 1998).

Tetrodotoxin is found in poisonous Japanese pufferfish (fugu, of the genus Fugu), and in several other poisonous animals, including globe fish, sun fish, trigger fish, the deadly blue-ringed octopus, frogs of the genus Atelopus, seastars, xantid crabs, horseshoe crabs, numerous marine snails, flatworms, sea squirts, etc. (Yotsu, et al., 1987; Yasumoto, et al., 1986; Noguchi, et al., 1987; Thuesen and Kogura, 1989). TTX has been found in four classes spanning four phyla, bringing up the question of where and how TTX is acquired by such diverse animals.

In 1984, Y. Shimizu's study of Japanese pufferfish showed that captive bred fugu lacked TTX, but acquired the toxin after consuming the livers of other TTX-possessing pufferfish. This led to the conclusion that the toxin was acquired from the natural habitat, i.e. the food chain (Yasumoto, et al. 1986). Shimizu hypothesized that TTX was acquired directly from ingestion of bacteria possessing the toxin, resulting in the toxification of the host organism in a symbiotic relationship (Shimizu, 1986). This would account for the wide variety of animals and habitats that TTX is found in. However, further studies by Yasumoto found that sympatric pufferfish similar to fugu accumulated TTX when ingested, but dissimilar sympatric fish did not. To add to the mystery, in 1995 Matsumura conducted a study on Shimizu's conclusions that dimmed the light on TTX's origins even more. Using technology that was unavailable in 1984, Matsumura discovered that captive bred fugu do in fact possess TTX, but in lower concentrations and in different tissues than wild fugu. The toxin in captive bred specimens is found in the skin and muscle tissue, whereas wild type fugu possessed high concentrations in the liver and gonads (Matsumura, 1996).

Although Matsumura's discovery seemed to contradict Shimizu's hypothesis, it is thought today that the toxin is acquired through the food chain from TTX-synthesizing bacteria. Through natural selection, pufferfish and other animals possessing TTX took advantage of a single-point mutation in the sodium channel that rendered them immune from the toxin (Kirsch et al., 1994; Penzotti et al., 1998). This enabled them to consume and adapt the poison to their systems without experiencing any ill repercussions. Similar spontaneous mutations are common in nature, but are not always advantageous to the organism.

Alteromonas spp. bacteria have been linked to the production of TTX in pufferfish, and several other marine species (Yotsu, et al., 1987; Yasumoto, et al., 1986). TTX has also been found in Vibrio spp. bacteria that were isolated from the intestines of xantid crads, tetraodontid fishes, and four chaetognath species (Noguchi, et al., 1987; Thuesen and Kogura, 1989). Alteromonas spp. and Vibrio spp. are thought to enter marine host organisms through the consumption of red calcareous algae (Jania spp.) possessing the bacteria. Vibrio spp. is thought to be the TTX-producing bacteria found in amphibians, however, it is unknown how the bacteria may have reached them.

Although tarichatoxin is only 1% as potent as TTX, toxic newts are capable of inflicting serious damage, and even death, to large mammals and other potential wild predators. Interestingly, the common garter snake, Thamnophis sirtalis, of North America is immune to the TTX-possessing rough-skinned newt, Taricha granulosa, which it often preys upon. The two species seem to be in an arms race, for as the newts become more toxic to counteract the snake’s immunity, the snakes become more immune to counteract the increasingly poisonous newts.

It has been shown that all poisonous newts possess TTX, with Taricha species being the most toxic and Triturus species being the least. It has also been shown that terrestrial juveniles (efts) are several times more toxic than adults.

For more information on the toxicity of newts and Tetrodotoxin, please read Article 0011 - Toxicity and Defense Methods of Amphibians.


 

References

ARMI National Atlas for Amphibian Distributions (Database). United States Geological Survey. http://www.mp2-pwrc.usgs.gov/armiatlas (Accessed: 2003).

Auyoung, Erick (1999). A Brief History and Overview of Tetrodotoxin (TTX). University of California, Berkeley. http://sulcus.berkeley.edu/mcb/165_001/papers/manuscripts/_317.html (Accessed: 2002)

Beltz, Ellin (2003). North American Reptile and Amphibian Names. Ellin Beltz. http://ebeltz.net/herps/etyhome.html (Accessed: 2001).

Fuhrman, F.A. Tetrodotoxin, Tarichatoxin, and Chiriquitoxin: Historical Perspectives. Chapter 1 (pp 1-13) in Tetrodotoxin, Saxitoxin, and the Molecular Biology of the Sodium Channel (Volume 479) (C.Y. Kao and S.R. Levinson editors). New York Academy of Sciences (1986).

Kirsch, G.E., Alam, M., & Hartmann, H.A. Differential effects of sulfhydryl reagents on saxitoxin and tetrodotoxin block of voltage-dependent sodium channels. Biophysical Journal 67(6): 2305-2315 (1994).

Light, William Haugan. 1998. Eye of Newt, Skin of Toad, Bile of Pufferfish.
   California Wild, Summer 1998 ( California Academy of Science).

Matsumura, K. Tetrodotoxin concentrations in cultured puffer fish, Fugu rubripes. Journal of Agricultural and Food Chemistry 44(1): 1-2 (1996).

Mosher, H.S. The Chemistry of Tetrodotoxin. Chapter 4 (pp 32-42) in Tetrodotoxin, Saxitoxin, and the Molecular Biology of the Sodium Channel (Volume 479) (C.Y. Kao and S.R. Levinson editors). New York Academy of Sciences (1986).

Nature Serve Explorer (Database). Nature Serve. http://www.natureserve.org/explorer/index.htm (Accessed: 2000-2003).

Obst, Fritz Jugen, Udo Jacob, and K. Richter. Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium.
   Neptune City, NY: T.F.H. Publications, Inc., 1989.

Penzotti, J.L. et al. Differences in saxitoxin and tetrodotoxin binding revealed by mutagenesis of the Na+ channel outer vestibule. Biophysical Journal 75(6): 2647-2657 (1998).

Petranka, James W. Salamanders of the United States and Canada.
   Smithsonian Institution Press, 1998.

Sheppard, Jessica. 1999. California's Noble Newt.
   California Wild, Winter 1999 ( California Academy of Sciences).

Shimizu, Y. Chemistry and Biochemistry of Saxitoxin Analogues and Tetrodotoxin. Chapter 3 (pp 24-30) in Tetrodotoxin, Saxitoxin, and the Molecular Biology of the Sodium Channel (Volume 479) (C.Y. Kao and S.R. Levinson editors). New York Academy of Sciences (1986).

Stebbins, Robert C. Western Reptiles and Amphibians (third edition).
   Houghton Mifflin Company, 2003.

Stebbins, Robert C., and Nathan W. Cohen. A Natural History of Amphibians.
   Princeton Paperbacks, 1997.

Yasumoto, T. et al. Interspecies Distribution and Possible Origin of Tetrodotoxin. Chapter 5 (pp 44-50) in Tetrodotoxin, Saxitoxin, and the Molecular Biology of the Sodium Channel (Volume 479) (C.Y. Kao and S.R. Levinson editors). New York Academy of Sciences (1986).

Other Resources
AmphibiaWeb (Taricha torosa entry)
AmphibiaWeb (Taricha granulosa entry)
AmphibiaWeb (Taricha rivularus entry)
Animal Diversity (Taricha torosa entry)
California Academy of Science (Taricha torosa entry)
Eye of Newt, Skin of Toad, Bile of Pufferfish (William Haugan Light)
California's Noble Newt (Jessica Sheppard)

 

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