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Taricha torosa, California newts, are divided into two subspecies:
The difference between these two seems to be only in the location in which they are found.
Range and habitat
California newts exist primarily on the California coastline and in the Sierra Nevada, because they prefer less humid climates than the rough-skinned newts. Outside the breeding season, the newts are land-dwelling, preferring rock crevices and logs.
While breeding, the subspecies Taricha torosa torosa prefers slow-moving water in coastal streams.
Reproduction occurs generally between December and early May. Typically, the adult newts will return to the pool in which they hatched. After a mating dance, the male mounts the female and rubs his chin on her nose. He then attaches a spermatophore to the substrate, which she will retrieve into her cloaca.
The egg mass released by the female contains between seven and 30 eggs, and is roughly the consistency of a thick gelatin dessert. Typically, the egg masses are attached to stream plant roots or to rocky crevices in small, pools of slow-moving water, but they have also been known to be attached to underwater rocks or leaf debris. While shallow in a wide sense, these pools are rather deep relative to the average depth of a Southern California stream, varying in depth from about 1–2 metres (3.3–6.6 ft).
Adult newts will stay in the pools throughout the breeding season, and can be occasionally found well into the summer. Larvae hatch sometime in early to midsummer, depending on local water temperature. Larvae are difficult to find in streams, as they blend in well with the sandy bottom, to which they usually stay close.
Toxicity and predation
Like other genus Taricha members, the glands in the skin of Taricha torosa secrete the potent neurotoxin tetrodotoxin, which is hundreds of times more toxic than cyanide. This is the same toxin found in pufferfish and harlequin frogs. Researchers believe bacteria synthesize tetrodotoxin, and the animals that employ the neurotoxin acquire it through consumption of these bacteria. This neurotoxin is strong enough to kill most vertebrates, including humans. However, it is dangerous only if ingested.
Due to their toxicity, California newts have few natural predators. Garter snakes are the most common, and some species have developed a genetic resistance to tetrodotoxin.
Earthworms, snails, slugs, sowbugs, bloodworms, mosquito larvae, crickets, and other invertebrates are among the California newt's prey. In the Sierra Nevada, the newt will also consume trout eggs. In an aquarium habitat, earthworms provide the newt with all necessary nutrients. Other natural prey items would benefit the captive newt. Pellets tend to be inappropriate for terrestrial caudates, and fish food should be avoided completely.
Taricha torosa, the California newt, is currently a California Special Concern species (DFG-CSC). Some populations have been greatly reduced in southern California coastal streams due to the introduction of non-native, invasive species and human habitation. The mosquitofish (Gambusia affinis) and red swamp crayfish (Procambarus clarkii) have caused the greatest reduction in newt populations.
Introduced as fish bait and stock pond prey, red swamp crayfish are an incredibly aggressive, prolific, and stalwart species that will prey upon newt larvae and egg masses. The crayfish will also disrupt newt breeding via competition for space during the summer mating season and physically antagonizing adults. Crayfish will typically maul the adult newts with their claws, and subsequent infection can lead to death. Taricha torosa is present in streams with introduced crayfish often sport tails with several notches removed. They are amphibians and live in humid areas.
- Hammerson (2004). Taricha torosa. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 12 May 2006. Database entry includes a range map and justification for why this species is of least concern
- San Diego Natural History Museum
|Wikimedia Commons has media related to Taricha torosa.|
|Wikispecies has information related to: Taricha torosa|
- California Herps.com: description of California newts (Taricha torosa) — California newt facts.
- Mister-toad.com: mating behavior of California newts — with video.
- Caudata.org: Culture of California newts (Taricha torosa) — guide to identifying species and keeping as a pet.