Rough-skinned Newt

Rough Skinned Newt

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Rough-skinned Newt

The rough-skinned newt (Taricha
Taricha

The genus Taricha consists of three species and four subspecies of Western Newts . All newts are part of the family Salamandridae. The three species within this genus are the California Newt, the Rough-Skinned Newt, and the Red Bellied Newt, all of which are found on the west coast of the USA....
granulosa) is a North America

North America

North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere....
n newt

Newt

A newt is a salamander that lives in the water as an adult. Newts occur in the Pleurodelinae subfamily , found in North America, Europe and Asia....
known for its strong poison. They are available in some places as pets, sometimes with names "Oregon newt" or "orange-bellied newt." However the "Oregon newt" is more than likely a newt from California that looks similar. Oregon does not allow the commercial sale of these newts.

. granulosa is divided into two subspecies.

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Subspecies

T. granulosa is divided into two subspecies. Both have rough or granular skin, except for breeding males, which additionally exhibit swollen vents and cornified toe pads.

The rough-skinned newt (T. g. granulosa) is light brown to brownish-black above with an orange or yellow belly. In some populations, the back has dark blotches. They are between 13 to 22 cm
Centimetre

A centimetre is a Units of measurement of length in the metric system, equal to one hundredth of a metre, which is the current International System of Units SI base unit of length....
long.
The Crater Lake newt or Mazama newt (T. g. mazamae) is darker above and brighter below than T. g. granulosa and may also have dark blotches below. The validity of this subspecies, which is exclusive to the region of Crater Lake
Crater Lake

Crater Lake is a caldera lake located in the U.S. state of Oregon. It is the main feature of Crater Lake National Park and famous for its deep blue color and water clarity....
, Oregon
Oregon

Oregon is a U.S. state in the Pacific Northwest region of the United States. The area was inhabited by many indigenous tribes before the arrival of traders, explorers and settlers....
, is disputed by some researchers because the newts on Gravina Island
Gravina Island

Gravina Island is an island in the Gravina Islands of the Alexander Archipelago in southeastern Alaska. It is long and about wide, with a land area of ....
, Alaska
Alaska

Alaska is the largest U.S. state of the United States by area; it is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait....
, are very similar.

Toxicity

Many newts produce toxins to avoid predation

Predation

In ecology, predation describes a biological interaction where a predator feeds on its prey, the organism that is attacked. Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of the prey....
, but the toxins of the genus Taricha

Taricha

The genus Taricha consists of three species and four subspecies of Western Newts . All newts are part of the family Salamandridae. The three species within this genus are the California Newt, the Rough-Skinned Newt, and the Red Bellied Newt, all of which are found on the west coast of the USA....
are particularly potent. One thirtieth of the toxin present in the skin of an average adult rough-skinned newt is sufficient to kill a healthy adult human. Toxicity is generally experienced only if the newt is ingested, although there are reports that some individuals experience skin irritation after dermal contact.

Toxin

The rough-skinned newt possesses tetrodotoxin

Tetrodotoxin

Tetrodotoxin is a potent neurotoxin with no known antidote. Tetrodotoxin blocks action potentials in nerves by binding to the pores of the voltage-gated, fast sodium channels in neuron cell membrane....
, which in this species was formerly called tarichatoxin. This toxin binds to sodium channels in nerve cells and interferes with the normal flow of sodium ions in and out of the cell. This has the effect of inducing paralysis and death.

Toxin Resistance and Predation

Throughout much of the newt’s range, the common garter snake

Common Garter Snake

The common garter snake is a snake indigenous to North America. Most garter snakes have a pattern of yellow stripes on a brown background and their average length is about to ....
(Thamnophis sirtalis) has been observed to exhibit resistance to the tetrodotoxin produced in its skin. While in principle the toxin binds to a tube shaped protein that acts as a sodium channel in the snake's nerve cells, researchers have identified a genetic disposition in several snake populations where the protein is configured in such a way as to hamper or prevent binding of the toxin. In each of these populations, the snakes exhibit resistance to the toxin and successfully prey upon the newts. Toxin resistant garter snakes are the only known animals today that can eat a T. granulosa newt and survive.

In evolutionary theory, the relationship between the rough-skinned newt and the common garter snake is considered an example of co-evolution

Co-evolution

In a broad sense, biological coevolution is "the change of a biological object triggered by the change of a related object". Coevolution can occur at multiple levels of biology: it can be as microscopic as correlated mutations between amino acids in a protein, or as macroscopic as covarying traits between different species in an environment...
. The mutations in the snake’s genes that conferred resistance to the toxin have resulted in a selective pressure that favors newts which produce more potent levels of toxin. Increases in newt toxicity then apply a selective pressure favoring snakes with mutations conferring even greater resistance. This cycle of a predator and prey evolving to one another is sometimes termed an evolutionary arms race

Evolutionary arms race

In evolutionary biology, an evolutionary arms race is an evolutionary struggle between competing sets of co-evolution genes that develop adaptation s and counter-adaptations against each other, resembling an arms race....
and has resulted in the newts producing levels of toxin far in excess of what is needed to kill any other conceivable predator.

Location

Habitats

Habitat (ecology)

A habitat is an ecological or Natural_environment area that is inhabited by a particular animal or plant species. It is the natural environment in which an organism lives, or the physical environment that surrounds a species population....
of rough-skinned newts are found throughout the west coast of the US. They are uncommon east of the Cascade Mountains though occasionally found (and considered exotic, and possibly artificially introduced) as far as Montana. The southern range extends to Santa Cruz

Santa Cruz, California

Santa Cruz is the county seat and largest city of Santa Cruz County, California, California in the United States of America. As of the United States Census, 2000, Santa Cruz had a total population of 54,593....
, California

California

California is a U.S. state on the West Coast of the United States of the United States, along the Pacific Ocean. It is bordered by Oregon to the north, Nevada to the east, Arizona to the southeast, and to the south the Mexico state of Baja California....
and as far north as Alaska

Alaska

Alaska is the largest U.S. state of the United States by area; it is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait....
.

Rough-skinned Newt

Subspecies

Toxicity

Toxin

Toxin Resistance and Predation

Location

Parasites

See also

Line notes

External links